WO2018136323A1 - Electrochemical apparatus and its use for screening of nanostructure catalysts - Google Patents

Electrochemical apparatus and its use for screening of nanostructure catalysts Download PDF

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Publication number
WO2018136323A1
WO2018136323A1 PCT/US2018/013493 US2018013493W WO2018136323A1 WO 2018136323 A1 WO2018136323 A1 WO 2018136323A1 US 2018013493 W US2018013493 W US 2018013493W WO 2018136323 A1 WO2018136323 A1 WO 2018136323A1
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gas chamber
catalyst sample
testing apparatus
gas
sample
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PCT/US2018/013493
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French (fr)
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Heli Wang
Ihab N. ODEH
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Sabic Global Technologies B.V.
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Publication of WO2018136323A1 publication Critical patent/WO2018136323A1/en

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/30Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
    • B01J35/39Photocatalytic properties
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M14/00Electrochemical current or voltage generators not provided for in groups H01M6/00 - H01M12/00; Manufacture thereof
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/86Inert electrodes with catalytic activity, e.g. for fuel cells
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30Hydrogen technology
    • Y02E60/50Fuel cells

Definitions

  • the present invention generally relates to catalysts used in industrial chemical processes. More specifically, the present invention relates to screening catalysts used in industrial chemical processes. BACKGROUND OF THE INVENTION
  • Catalysts accelerate chemical reactions.
  • the chemical reactions involved in these industrial processes may need to be accelerated by catalysts.
  • current commercial processes for methane to methanol conversion require two steps: (1) cracking of methane to carbon monoxide and hydrogen gas (syngas) at high temperature (800 °C) and high pressure (3.5 MPa) and (2) converting syngas to methanol over a catalyst (for instance, copper or platinum).
  • This two- step process is very energy intensive and has a low yield.
  • Methane to methanol conversion with one-step direct oxidation can have cost advantages. For instance, partial oxidation of methane at 350-500 °C is under development industrywide and catalysts like Cu/SiC , WO3, V2O5 and Mo-V-Cr-Bi-Ox/SiC have been evaluated for this process. However, low yield and low selectivity of these catalysts have been a challenge, and high level of oxygen in the reactor poses a safety risk. In addition to this, the development of catalysts is a lengthy and costly process.
  • molecular catalysts like platinum bipyridine or covalent triazine-based framework containing platinum/bipyridine
  • oxidize to methyl bisulfate at approximately 200 °C which is subsequently hydrolyzed to methanol
  • the apparatus and method of use provides at least the following advantages 1) plasmonic nanostructures can be utilized, 2) low temperature reaction conditions ⁇ e.g., up to 100 °C, but preferably less than 60 °C), 3) a gas electrode design, 4) separated gas and liquid chambers for simplified electrochemical control; and 5) simplified catalyst loading.
  • the systems and methods utilize plasmonic nanostructures in a screening process that can take place at room temperature.
  • Embodiments of the invention include a method of testing the effectiveness of a catalyst sample on a reaction that includes a gaseous reactant.
  • the method can include: (a) preparing the catalyst sample to include plasmonic nanostructures deposited on an electrode membrane; (b) positioning a working electrode that includes the catalyst sample between a gas chamber and a liquid chamber in an electrochemical cell in a manner so that the catalyst sample is in contact with gaseous content of the gas chamber, the working electrode is in electrical communication with a counter electrode and a reference electrode of the electrochemical cell; (c) flowing a feed that includes the gaseous reactant (e.g., a hydrocarbon gas, nitrogen, or the like) into the gas chamber; (d) measuring the amount of feed that flows into the gas chamber; (e) exposing the plasmonic nanostructures to light for a set period of time sufficient to cause a first half reaction in the gas chamber and a second half reaction in the liquid chamber and thereby cause an overall reaction that forms a product in the gas chamber; and (f
  • the gaseous reactant is a gaseous hydrocarbon and the product can be an alcohol.
  • catalysts for the product of gaseous methane to methanol can be evaluated.
  • the gaseous reactant can be nitrogen and the product can include ammonia.
  • Plasmonic nanostructure can include platinum (Pt), palladium (Pd), ruthenium (Ru), silver (Ag), gold (Au), copper (Cu) or any combination or any alloy thereof.
  • the catalyst can include a transition metal oxide (e.g., CuO, Ga 2 03, ImCb, NiO, Sn0 2 , Ce0 2 , M0O3, or WO3, or any combination thereof).
  • the catalyst sample can also include a promoter, preferably a nanostructure promoter and optionally a support (e.g., T1O2 or S1O2).
  • testing parameters can be varied.
  • the size of the plasmonic nanostructures can be varied, the plasmonic nanostructures can be doped, or reaction conditions such as temperature, pressure, or reactant flow rates, or any combination thereof can be modified.
  • the plasmonic nanostructures can be nanorods, nanospheres, nanotubes, or combinations thereof, preferably nanorods.
  • the reaction temperature is up to 100 °C, or less than 60 °C, or in a range of 5 °C to 45 °C.
  • Embodiments of the invention can include a testing apparatus for carrying out bench scale tests on a catalyst sample that includes plasmonic nanostructures.
  • the testing apparatus can include: (a) a gas chamber defined by one or more walls that can include a wall that is transparent to light, the gas chamber adapted to receive a gaseous reactant; (b) a liquid chamber defined by one or more walls, the liquid chamber adapted to contain liquid electrolyte; and (c) a working electrode that is adapted to receive the catalyst sample, the working electrode positioned between the gas chamber and the liquid chamber in a manner so that, in operation, the catalyst sample is in contact with gaseous content of the gas chamber, the working electrode being part of an electrochemical cell of the testing apparatus.
  • the working electrode can include an ion exchange membrane in contact with an electrical conductor.
  • the ion exchange membrane can include a polymer.
  • the testing apparatus of can further include (a) a counter electrode disposed in the liquid electrolyte; and (b) a reference electrode disposed in the liquid electrolyte, where the working electrode, counter electrode, and reference electrode are in electrical communication as part of the electrochemical cell.
  • the testing apparatus can also include (a) an inlet to the gas chamber adapted for receiving the gas and in fluid communication with an apparatus for measuring an amount of gas flowing through the inlet to the gas chamber, and (b) an outlet from the gas chamber adapted to flowing product away from the gas chamber and in fluid communication with an apparatus for measuring an amount of product flowing through the outlet from the gas chamber.
  • the surface area of the sample can range from 0.1 cm 2 to 1000 cm 2 .
  • the weight and/or size of the testing equipment can fall into a range of 0.05 kg to 400 kg.
  • the testing apparatus can be so adapted that carrying out a test on a first catalyst sample, changing the first catalyst sample to a second catalyst sample, and testing the second catalyst sample takes a period of time in a range of 0.1 h to 100 h.
  • the testing apparatus can be configured to test the effectiveness of an electrocatalyst sample and/or photocatalyst sample and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant.
  • Embodiments of the invention also include methods of testing the effectiveness of a catalyst and/or electrocatalyst sample and/or photocatalyst sample and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant, the method comprising using the testing apparatus of the present invention.
  • Embodiment 1 is A method of testing the effectiveness of a catalyst sample on a gaseous reactant, the method comprising: (a) preparing the catalyst sample to include plasmonic nanostructures deposited on an electrode membrane; (b) positioning a working electrode that includes the catalyst sample between a gas chamber and a liquid chamber in an electrochemical cell in a manner so that the catalyst sample is in contact with gaseous content of the gas chamber, the working electrode is in electrical communication with a counter electrode and a reference electrode of the electrochemical cell; (c) flowing a feed that includes the gaseous reactant into the gas chamber; (d) measuring the amount of feed that flows into the gas chamber; (e) exposing the plasmonic nanostructures to light for a set period of time sufficient to cause a first half reaction in the gas chamber and a second half reaction in the liquid chamber and thereby cause an overall reaction that forms a product in the gas chamber; and (f) measuring the amount of the product in relation to the amount of the feed flowed out of the gas chamber.
  • Embodiment 2 is the method of embodiment 1, wherein the gaseous reactant comprises a gaseous hydrocarbon and the product comprises an alcohol, or gaseous nitrogen and the product comprises ammonia.
  • Embodiment 3 is the method of any of embodiments 1 and 2, wherein the plasmonic nanostructures comprise platinum (Pt), palladium (Pd), ruthenium (Ru), silver (Ag), gold (Au), copper (Cu) or any combination or any alloy thereof.
  • Embodiment 4 is the method of any of embodiments 1 to 3, wherein the catalyst sample further comprises a transition metal or oxide thereof, or lanthanide or oxide thereof V2O5, CuO, Ga 2 03, ImCb, NiO, Sn0 2 , Ce0 2 , M0O3, or WO3, or any combination thereof.
  • Embodiment 5 is the method of any of embodiments 1 to 4, wherein the catalyst sample comprises a promoter, preferably a nanostructure promoter.
  • Embodiment 6 is the method of any of embodiments 1 to 5, further comprising varying testing parameters selected from modifying the size of the plasmonic nanostructures, doping the plasmonic nanostructures, or modifying the reaction conditions such as temperature, pressure, or reactant flow rates, or any combination thereof.
  • Embodiment 7 is the method of any one of embodiments 1 to 6, wherein the plasmonic nanostructures comprise nanorods, nanospheres, nanotubes, or combinations thereof, preferably nanorods.
  • Embodiment 8 is the method of any one of embodiments 1 to 7, wherein the catalyst further includes a support.
  • Embodiment 9 is the method of any of embodiments 1 to 8, wherein the reaction temperature is up to 100 °C.
  • Embodiment 10 is the method of any of embodiments 1 to 9, wherein the reaction temperature is in a range 5 °C to 45 °C.
  • Embodiment 1 1 is a testing apparatus for carrying out bench scale tests on a catalyst sample that includes plasmonic nanostructures, the testing apparatus comprising: (a) a gas chamber defined by one or more walls that comprise a wall that is transparent to light, the gas chamber adapted to receive a reactant gas; (b) a liquid chamber defined by one or more walls, the liquid chamber adapted to contain liquid electrolyte; and (c) a working electrode that is adapted to receive the catalyst sample, the working electrode positioned between the gas chamber and the liquid chamber in a manner so that, in operation, the catalyst sample is in contact with gaseous content of the gas chamber, the working electrode being part of an electrochemical cell of the testing apparatus.
  • Embodiment 12 is the testing apparatus of embodiment 11, wherein the working electrode comprises an ion exchange membrane in contact with an electrical conductor.
  • Embodiment 13 is the testing apparatus of embodiment 12, wherein the ion exchange membrane comprises a polymer.
  • Embodiment 14 is the testing apparatus of any of embodiments 12 to 13, further comprising: (a) a counter electrode disposed in the liquid electrolyte; and (b) a reference electrode disposed in the liquid electrolyte, wherein the working electrode, counter electrode, and reference electrode are in electrical communication as part of the electrochemical cell.
  • Embodiment 15 is the testing apparatus of any of embodiments 12 to 14, further comprising: (c) an inlet to the gas chamber adapted for receiving the gas and in fluid communication with an apparatus for measuring an amount of gas flowing through the inlet to the gas chamber; and (d) an outlet from the gas chamber adapted to flowing product away from the gas chamber and in fluid communication with an apparatus for measuring an amount of product flowing through the outlet from the gas chamber.
  • Embodiment 16 is the testing apparatus of any of embodiments 11 to 15, wherein the surface area of the sample is in a range of 0.1 cm 2 to 1000 cm 2 .
  • Embodiment 17 is the testing apparatus of any of embodiments 11 to 16 wherein the weight and/or size of the testing equipment fall into a range of 0.05 kg to 400 kg.
  • Embodiment 18 is the testing apparatus of any of embodiments 11 to 17 wherein the testing apparatus is so adapted that carrying out a test on a first catalyst sample, changing the first catalyst sample to a second catalyst sample, and testing the second catalyst sample takes a period of time in a range of 0.1 h to 100 h.
  • Embodiment 19 is the testing apparatus of any of embodiments 11 to 18, wherein the testing apparatus is configured to test the effectiveness of an electrocatalyst sample and/or photocatalyst sample and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant.
  • Embodiment 20 is a method of testing the effectiveness of a catalyst and/or electrocatalyst sample and/or photocatalyst sample and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant, the method comprising using the testing apparatus of any of embodiments 11 to 19.
  • Nanostructure or “nanomaterial” refer to an object or material in which at least one dimension of the object or material is equal to or less than 1000 nm (e.g., one dimension is 1 to 1000 nm in size).
  • the nanostructure includes at least two dimensions that are equal to or less than 1000 nm (e.g., a first dimension is 1 to 1000 nm in size and a second dimension is 1 to 1000 nm in size).
  • the nanostructure includes three dimensions that are equal to or less than 100,000 nm (e.g., a first dimension is 1 to 1000 nm in size, a second dimension is 1 to 1000 nm in size, and a third dimension is 1 to 1000 nm in size).
  • the shape of the nanostructure can be of a wire, a particle (e.g., having a substantially spherical shape), a rod, a tetrapod, a hyper-branched structure, a tube, a cube, or mixtures thereof.
  • Nanoparticles include particles having an average diameter size of 1 to 1000 nanometers.
  • wt.% refers to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or the total moles of material that includes the component.
  • 10 moles of component in 100 moles of the material is 10 mol.% of component.
  • FIG. 1 shows a gas electrode for testing the effectiveness of a catalyst sample on a reaction that includes a hydrocarbon gas as a reactant according to embodiments of the invention.
  • FIG. 2 shows an electrochemical cell, based on polymer electrolyte membrane
  • FIG. 3 shows a method for testing the effectiveness of a catalyst sample on a reaction that includes a hydrocarbon gas as a reactant according to embodiments of the invention.
  • Embodiments of the invention can include a plasmon enhanced electrochemical route for a chemical process.
  • Such chemical processes may include methane oxidation (e.g., methane to methanol conversion).
  • Incorporating electrochemistry with plasmonic nanostructures, according to embodiments of the invention, can provide additional flexibility in designing materials for methane activation, since the reaction involving methane activation can be controlled at a desired potential so that the kinetics and reaction selectivity can be improved.
  • anodic and cathodic half reactions in embodiments of the invention, occur at separate chambers (electrodes), thus the reaction products can be collected in separate chambers.
  • methane to methanol conversion will be used as the process in which the embodiments are applied. It should be noted, however, that embodiments of the invention are applicable to other chemical processes.
  • FIG. 1 shows gas electrode 10 for testing the effectiveness of a catalyst sample on a reaction.
  • Gas electrode 10 may be used with a reactive gas (e.g., a hydrocarbon gas as a reactant or gaseous nitrogen).
  • Gas electrode 10, as shown in FIG. 1, is designed to include catalyst 100 deposited on polymer electrolyte membrane 101 (e.g., an ion exchange membrane). Polymer electrolyte membrane 101 and catalyst 100 are in contact with ring 102.
  • Ring 102 can include a metal, for example, a Gold (Au) ring.
  • Catalyst 100 can include plasmonic nanostructures. Plasmonic nanostructures can act either as catalysts themselves, or as promoters to enhance the catalytic reaction.
  • FIG. 2 shows electrochemical cell 20, based on a polymer electrolyte membrane (PEM), for testing the effectiveness of a catalyst sample on a reaction that includes a gaseous reactant (e.g., a hydrocarbon gas as a reactant).
  • electrochemical cell 20 may be a testing apparatus for carrying out bench scale tests on a catalyst sample that includes plasmonic nanostructures.
  • Electrochemical cell 20, can include liquid chamber 202, gas chamber 203, and working electrode 200. Liquid chamber 202 can be defined by one or more walls and be adapted to contain liquid electrolyte.
  • Working electrode 200 can be adapted to receive plasmonic nanostructures 210 (e.g., a catalyst sample) on polymer electrolyte membrane 21 1, both of which are in contact with metal ring 212.
  • the catalyst sample is deposited on working electrode 200.
  • Plasmonic nanostructures 210 can be applied to working electrode 200 either as catalysts or as catalysis promoters.
  • gas electrode 10 can be working electrode 200 in electrochemical cell 20.
  • Working electrode 200 may be positioned between gas chamber 203 and liquid chamber 202 in a manner so that, in operation, the catalyst sample is in contact with gaseous content of gas chamber 203.
  • Gas chamber 203 can be defined by one or more walls that include a wall that is transparent to light and be adapted to receive a reactant gas. As shown, gas chamber 203 includes a section 201 transparent to light so that light beam 214 can pass through gas chamber 203 and impinge on working electrode 200 and plasmonic nanostructures 210 disposed thereon. In embodiments of the invention, the section of gas chamber 203 that is transparent to light may be a quartz window. [0034] Photocatalysts can be evaluated and developed with electrochemical cell 20.
  • electrochemical cell 20 may be a testing apparatus adapted to test the effectiveness of an electrocatalyst and/or photocatalyst and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant.
  • electrochemical cell 20 may also include counter electrode 206 and/or reference electrode 207, disposed in liquid electrolyte 208.
  • Working electrode 200, counter electrode 206, and reference electrode 207, in embodiments of the invention, are all in electrical communication, as part of electrochemical cell 20.
  • electrochemical cell 20 includes gas inlet 204 connected to gas chamber 203.
  • Gas inlet 204 leads into gas chamber 203 and is adapted for receiving gas and channeling the gas into gas chamber 203.
  • electrochemical cell 20 includes gas outlet 205 connected to gas chamber 203. Gas outlet 205 leads from gas chamber 203 and is adapted for flowing product away from gas chamber 203.
  • electrochemical cell 20 includes flow meter 209 for measuring an amount of gas flowing through gas inlet 204 to the gas chamber and flow meter 213 for measuring an amount of product flowing through gas outlet 205 from gas chamber 203.
  • electrochemical cell 20 as a testing apparatus, is of a size and configuration so that it can be used to carry out bench scale tests to determine the effectiveness of catalysts on chemical processes.
  • electrochemical cell 20 can include a sample with a surface area in a range of 0.1 cm 2 to 1000 cm 2 , and all ranges and values there between including ranges 0.1 cm 2 to 25 cm 2 , 25 cm 2 to 50 cm 2 , 50 cm 2 to 75 cm 2 , 75 cm 2 to 100 cm 2 , 100 cm 2 to 125 cm 2 , 125 cm 2 to 150 cm 2 , 150 cm 2 to 175 cm 2 , 175 cm 2 to 200 cm 2 , 200 cm 2 to 225 cm 2 , 225 cm 2 to 250 cm 2 , 250 cm 2 to 275 cm 2 , 275 cm 2 to 300 cm 2 , 300 cm 2 to 325 cm 2 , 325 cm 2 to 350 cm 2 , 350 cm 2 to 375 cm 2 , 375 cm 2 to 400 cm
  • a bench scale configuration of electrochemical cell 20, has a weight in a range of 0.05 kg to 400 kg and/or 0.1 lb to 800 lb, and all ranges and values there between including ranges 0.1 lb to 20 lb, 20 lb to 40 lb, 40 lb to 60 lb, 60 lb to 80 lb, 80 lb to 100 lb, 100 lb to 120 lb, 120 lb to 140 lb, 140 lb to 160 lb, 160 lb to 180 lb, 180 lb to 200 lb, 200 lb to 220 lb, 220 lb to 240 lb, 240 lb to 260 lb, 260 lb to 280 lb, 280 lb to 300 lb, 300 lb to 320 lb, 320 lb to 340 lb, 340 lb to 360
  • electrochemical cell 20 may be adapted to carry out tests on catalyst samples much more quickly than if tests were carried out in an industrial setting.
  • electrochemical cell 20 as a testing apparatus, is so adapted that carrying out a test on a first catalyst sample, changing the first catalyst sample to a second catalyst sample, and testing the second catalyst sample takes a period of time in a range of 0.1 h to 100 h, and all ranges and values there between including ranges 0.1 h to 1 h, 1 h to 5 h, 5 h to 10 h, 10 h to 15 h, 15 h to 20 h, 20 h to 25 h, 25 h to 30 h, 30 h to 35 h, 35 h to 40 h, 40 h to 45 h, 45 h to 50 h, 50 h to 55 h, 55 h to 60 h, 60 h to 65 h, 65 h to
  • FIG. 3 shows method 30 for testing the effectiveness of a catalyst sample on a reaction that includes a gaseous reactant; according to embodiments of the invention.
  • Method 30 may be implemented by electrochemical cell 20, as a testing apparatus.
  • the gaseous reactant can be any compound that can be gasified.
  • the gaseous reactant can be an organic compound, nitrogen, carbon dioxide, carbon monoxide, or the like.
  • Organic compounds can include hydrocarbons, heteroatom containing compounds or the like.
  • Hydrocarbons can include compounds having 1 to 20 carbon atoms.
  • Non-limiting examples of hydrocarbons include methane, ethane, ethylene, propane, propenes, butanes, butene, pentanes, pentenes, hexanes, hexenes, heptanes, heptenes, benzene, and the like.
  • Non-limiting example of heteroatom compounds include alcohols, amines, carboxylic acids, nitriles, acetates, thiols, thioethers, heterocyclic compounds, and the like.
  • Method 30, as implemented with electrochemical cell 20, may include, at block
  • the catalyst sample can be plasmonic nanostructures alone, or in combination with other materials (e.g., support materials, or other catalytic metals).
  • the plasmonic nanostructures may include platinum (Pt), palladium (Pd), ruthenium (Ru), silver (Ag), gold (Au), copper (Cu) or any combination or any alloy thereof.
  • the catalyst sample can include a transition metal or oxide thereof, a lanthanide or a chalcogenides metal chalcogenides. Transition metals can include one or more metals from Columns 5 to 12 of the Periodic Table.
  • Non-limiting examples of transition metal oxides include V2O5, CuO, Ga 2 0 3 , ImCb, NiO, Sn0 2 , M0O3, or WO3, or any combination thereof.
  • the catalyst can include a lanthanide (e.g., Ce0 2 , La 2 0 3 , or the like).
  • Non-limiting examples of chalcogenides include sulfides (S), selenides (Se) and the like.
  • the catalyst sample may include a promoter, preferably a nanostructure promoter. Promoters can include one or more metals from Columns 1 and 2 of the Periodic Table).
  • Non-limiting examples of promoters include sodium (Na), magnesium (Mg), potassium (K), cesium (Cs), barium (Ba), and the like.
  • the plasmonic nanostructures can have any shape or form.
  • the plasmonic nanostructures can be nanorods, nanospheres, nanotubes, or the like.
  • the plasmonic nanostructures are nanorods.
  • the aspect ratios of the nanorods can be tuned to control the plasmonic effectiveness of the catalyst sample.
  • the plasmonic nanostructures can be deposited on a support to form the catalyst sample.
  • the support can be a metal oxide, a photoactive semiconductor material, or the like.
  • the support can include T1O2, S1O2, AI2O3, TS-1, or the like.
  • the plasmonic nanostructure can have a core/shell type structure.
  • the catalyst can include a plasmonic metal core in a shell structure.
  • core/shell type structures include Au@Ti0 2 , Au@Si0 2 , or the like.
  • preparing the catalyst sample may include, for example, applying nanomaterial based catalysts, with or without support, onto the membrane by cost-effective methods like doctor blading, screen printing, spraying, dip-coating and inkjet printing.
  • method 30, as implemented with electrochemical cell 20 may include, at block 301, positioning working electrode 200, which includes the catalyst sample, between gas chamber 203 and liquid chamber 202 in electrochemical cell 20 in a manner so that the catalyst sample is in contact with gaseous content of gas chamber 203, while working electrode 200 is in electrical communication with counter electrode 206 and reference electrode 207 of electrochemical cell 20.
  • Method 30, as implemented with electrochemical cell 20 may further include flowing a feed that includes the gaseous reactant into gas chamber 203 and measuring the amount of feed that flows into gas chamber 203, at blocks 302 and 303, respectively.
  • method 30 involves exposing the plasm onic nanostructures to light for a set period of time sufficient to cause a first half reaction in the gas chamber and a second half reaction in the liquid chamber and thereby cause an overall reaction that forms a product in the gas chamber.
  • method 30 may include varying testing parameters selected from: modifying the size of the plasmonic nanostructures, doping the plasmonic nanostructures, or modifying the reaction conditions such as temperature, pressure, or reactant flow rates, or any combination thereof.
  • the reaction temperature is up to 100 °C, and all ranges and values there between including at least, equal to or between any two of 0 °C, 1 °C, 2 °C, 3 °C, 4 °C, 5 °C, 6 °C, 7 °C, 8 °C, 9 °C, 10 °C, 11 °C, 12 °C, 13 °C, 14 °C, 15 °C, 16 °C, 17 °C, 18 °C, 19 °C, 20 °C, 21 °C, 22 °C, 23 °C, 24 °C, 25 °C, 26 °C, 27 °C, 28 °C, 29 °C, 30 °C, 31 °C, 32 °C, 33 °C, 34 °C, 35 °C, 36 °C, 37 °C, 38 °C, 39 °C, 40 °C, 41 °C, 42 °C, 43
  • method 30 may involve measuring the amount of the product produced and flowed from gas chamber 203 in relation to the amount of the feed flowed out of gas chamber 203.
  • electrochemical cell 20 is operated at room temperature procedure, as compared with 60 to 120 °C for current state of the art electrochemical cells.
  • methane/water vapor stream is fed as input in gas chamber 203 through gas inlet 204. Quartz window of gas chamber 203 allows a light path needed for plasmonic nanostructures 210.
  • a platform with significant advantage for working electrode 200 acts as the catalytic site, and a half-reaction proceeds on working electrode 200 as reaction (1) on the catalyst at a desired potential for conversion of the gaseous reactant to the product.
  • gaseous methane to methanol conversion gaseous methane to methanol conversion.
  • the generated protons can transfer through polymer electrolyte membrane 21 1 (for instance, Nafion®) to participate in a hydrogen evolution reaction (HER) at counter electrode 206, which is immersed into electrolyte in liquid chamber 202, as reaction (2).
  • screening of catalysts for ammonia synthesis can be performed using the electrochemical cell 20.
  • Gaseous nitrogen can be reduced in the gaseous chamber upon contact with the plasmonic nanostructure, while the liquid chamber can be used for the oxidation reaction (e.g., water splitting).
  • the overall reaction using water in the liquid chamber is shown in equation (4)
  • electrochemical cell 20 favors the mass transfer of gaseous reactants (e.g., methane or nitrogen) in gas chamber 203, and avoids any possible impurities in the solution (liquid chamber 202) that may affect the selectivity and stability of the catalysts.
  • gaseous reactants e.g., methane or nitrogen
  • Another advantage of the design is that the existing catalysts for a process and those under development can be directly applied on working electrode 200, which provides a direct comparison.

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Abstract

A method for screening catalysts for use in chemical processes is disclosed. The method utilizes plasmonic nanostructures in a screening process that can take place at room temperature. A testing apparatus for screening catalysts for use in chemical processes is disclosed. The testing apparatus utilizes plasmonic nanostructures in a screening process that can take place at low temperatures such as room temperature.

Description

ELECTROCHEMICAL APPARATUS AND ITS USE FOR SCREENING OF
NANOSTRUCTURE CATALYSTS
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit to U.S. Provisional Application No. 62/449,273 filed January 23, 2017, which is incorporated herein by reference in its entirety.
FIELD OF INVENTION
[0002] The present invention generally relates to catalysts used in industrial chemical processes. More specifically, the present invention relates to screening catalysts used in industrial chemical processes. BACKGROUND OF THE INVENTION
[0003] Catalysts accelerate chemical reactions. In order for certain industrial processes to be commercially viable, the chemical reactions involved in these industrial processes may need to be accelerated by catalysts. For example, current commercial processes for methane to methanol conversion require two steps: (1) cracking of methane to carbon monoxide and hydrogen gas (syngas) at high temperature (800 °C) and high pressure (3.5 MPa) and (2) converting syngas to methanol over a catalyst (for instance, copper or platinum). This two- step process is very energy intensive and has a low yield.
[0004] Methane to methanol conversion with one-step direct oxidation can have cost advantages. For instance, partial oxidation of methane at 350-500 °C is under development industrywide and catalysts like Cu/SiC , WO3, V2O5 and Mo-V-Cr-Bi-Ox/SiC have been evaluated for this process. However, low yield and low selectivity of these catalysts have been a challenge, and high level of oxygen in the reactor poses a safety risk. In addition to this, the development of catalysts is a lengthy and costly process.
[0005] Another approach for producing methanol from methane, is the selective oxidation of methane in concentrated H2SO4. In this case, molecular catalysts (like platinum bipyridine or covalent triazine-based framework containing platinum/bipyridine) can be used to oxidize to methyl bisulfate at approximately 200 °C, which is subsequently hydrolyzed to methanol (See, Periana et. al. "Platinum catalysts for the high-yield oxidation of methane to a methanol derivative", Science, April 1998, Vol. 280, p. 560; and Palkovits et. al., "Solid catalysts for the selective low-temperature oxidation of methane to methanol", Angew. Chem. Int. Ed. 2009, 48, 6909-6912). These processes suffer in that it is challenging to maintain the stability and recylability of molecular catalysts in hot H2SO4.
[0006] Partial oxidation of Ci to C3 paraffins (including methane to methanol conversion) with H2O2 and a thin layer carbon-supported catalyst on Nafion support in a membrane reactor (3PCMR) has been described by Parmaliana et al. ("Selective partial oxidation of light paraffins with hydrogen peroxide on thin-layer supported Nafion-H catalysts", Catalysis Lett. 199, 12; p. 353-360). In this study, catalysts were tested both in gas and liquid phases, in a temperature range of 60 to 120 °C, at 1.4 bar. An alternative method practiced involved using high temperature proton conductive electrolyte for electrocatalytic methane coupling is described by Woldman et al. ("Electocatalytic methane coupling in the absence of oxygen on a high-temperature proton-conductive electrolyte", Catalysis Today, 1991, 8; p. 61-66.).
[0007] Selective formation of methanol from methane with different catalysts on a proton conductor (Snoidno.iPiC ) in a fuel cell-type reactor has been described by Lee et al. ("Efficient and selective formation of methanol from methane in a fuel cell-type reactor", J. Catalysis, 2011, 279; p. 233-240, Scheme 1.). In this case, two sides of a membrane can be supplied with gases. V20s/Sn02 was considered the best catalyst, with vanadium species being the active site for the formation of oxygen species. This process suffers from poor reaction efficiency and selectivity. [0008] As described above, current technologies with existing catalysts for methane oxidation usually have low product selectivity, low yield and often lead to over-oxidation. Thus, technologies and catalysts that are economically scalable and have limited adverse environmental impact are desirable.
BRIEF SUMMARY OF THE INVENTION [0009] Systems and methods have been discovered that provides solutions to determining the effectiveness of catalysts in reactions. The discovery is premised on the use of an electrochemical apparatus that provides an elegant and cost efficient way to evaluate catalysts for chemical reaction. By way of example, the apparatus and method of use provides at least the following advantages 1) plasmonic nanostructures can be utilized, 2) low temperature reaction conditions {e.g., up to 100 °C, but preferably less than 60 °C), 3) a gas electrode design, 4) separated gas and liquid chambers for simplified electrochemical control; and 5) simplified catalyst loading. In particular, the systems and methods utilize plasmonic nanostructures in a screening process that can take place at room temperature.
[0010] Embodiments of the invention include a method of testing the effectiveness of a catalyst sample on a reaction that includes a gaseous reactant. The method can include: (a) preparing the catalyst sample to include plasmonic nanostructures deposited on an electrode membrane; (b) positioning a working electrode that includes the catalyst sample between a gas chamber and a liquid chamber in an electrochemical cell in a manner so that the catalyst sample is in contact with gaseous content of the gas chamber, the working electrode is in electrical communication with a counter electrode and a reference electrode of the electrochemical cell; (c) flowing a feed that includes the gaseous reactant (e.g., a hydrocarbon gas, nitrogen, or the like) into the gas chamber; (d) measuring the amount of feed that flows into the gas chamber; (e) exposing the plasmonic nanostructures to light for a set period of time sufficient to cause a first half reaction in the gas chamber and a second half reaction in the liquid chamber and thereby cause an overall reaction that forms a product in the gas chamber; and (f) measuring the amount of the product in relation to the amount of the feed flowed out of the gas chamber. In some embodiments, the gaseous reactant is a gaseous hydrocarbon and the product can be an alcohol. By way of example, catalysts for the product of gaseous methane to methanol can be evaluated. In another embodiments, the gaseous reactant can be nitrogen and the product can include ammonia. Plasmonic nanostructure can include platinum (Pt), palladium (Pd), ruthenium (Ru), silver (Ag), gold (Au), copper (Cu) or any combination or any alloy thereof. In some instances, the catalyst can include a transition metal oxide (e.g., CuO, Ga203, ImCb, NiO, Sn02, Ce02, M0O3, or WO3, or any combination thereof). The catalyst sample can also include a promoter, preferably a nanostructure promoter and optionally a support (e.g., T1O2 or S1O2). In some embodiment, testing parameters can be varied. By way of example, the size of the plasmonic nanostructures can be varied, the plasmonic nanostructures can be doped, or reaction conditions such as temperature, pressure, or reactant flow rates, or any combination thereof can be modified. The plasmonic nanostructures can be nanorods, nanospheres, nanotubes, or combinations thereof, preferably nanorods. In some embodiments, the reaction temperature is up to 100 °C, or less than 60 °C, or in a range of 5 °C to 45 °C. [0011] Embodiments of the invention can include a testing apparatus for carrying out bench scale tests on a catalyst sample that includes plasmonic nanostructures. The testing apparatus can include: (a) a gas chamber defined by one or more walls that can include a wall that is transparent to light, the gas chamber adapted to receive a gaseous reactant; (b) a liquid chamber defined by one or more walls, the liquid chamber adapted to contain liquid electrolyte; and (c) a working electrode that is adapted to receive the catalyst sample, the working electrode positioned between the gas chamber and the liquid chamber in a manner so that, in operation, the catalyst sample is in contact with gaseous content of the gas chamber, the working electrode being part of an electrochemical cell of the testing apparatus. The working electrode can include an ion exchange membrane in contact with an electrical conductor. In some embodiments, the ion exchange membrane can include a polymer. In one embodiment, the testing apparatus of can further include (a) a counter electrode disposed in the liquid electrolyte; and (b) a reference electrode disposed in the liquid electrolyte, where the working electrode, counter electrode, and reference electrode are in electrical communication as part of the electrochemical cell. The testing apparatus can also include (a) an inlet to the gas chamber adapted for receiving the gas and in fluid communication with an apparatus for measuring an amount of gas flowing through the inlet to the gas chamber, and (b) an outlet from the gas chamber adapted to flowing product away from the gas chamber and in fluid communication with an apparatus for measuring an amount of product flowing through the outlet from the gas chamber. In some aspects, the surface area of the sample can range from 0.1 cm2 to 1000 cm2. In a particular aspect, the weight and/or size of the testing equipment can fall into a range of 0.05 kg to 400 kg. The testing apparatus can be so adapted that carrying out a test on a first catalyst sample, changing the first catalyst sample to a second catalyst sample, and testing the second catalyst sample takes a period of time in a range of 0.1 h to 100 h. In certain embodiments, the testing apparatus can be configured to test the effectiveness of an electrocatalyst sample and/or photocatalyst sample and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant.
[0012] Embodiments of the invention also include methods of testing the effectiveness of a catalyst and/or electrocatalyst sample and/or photocatalyst sample and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant, the method comprising using the testing apparatus of the present invention.
[0013] In one aspect of the present invention 20 embodiments are described.
Embodiment 1 is A method of testing the effectiveness of a catalyst sample on a gaseous reactant, the method comprising: (a) preparing the catalyst sample to include plasmonic nanostructures deposited on an electrode membrane; (b) positioning a working electrode that includes the catalyst sample between a gas chamber and a liquid chamber in an electrochemical cell in a manner so that the catalyst sample is in contact with gaseous content of the gas chamber, the working electrode is in electrical communication with a counter electrode and a reference electrode of the electrochemical cell; (c) flowing a feed that includes the gaseous reactant into the gas chamber; (d) measuring the amount of feed that flows into the gas chamber; (e) exposing the plasmonic nanostructures to light for a set period of time sufficient to cause a first half reaction in the gas chamber and a second half reaction in the liquid chamber and thereby cause an overall reaction that forms a product in the gas chamber; and (f) measuring the amount of the product in relation to the amount of the feed flowed out of the gas chamber. Embodiment 2 is the method of embodiment 1, wherein the gaseous reactant comprises a gaseous hydrocarbon and the product comprises an alcohol, or gaseous nitrogen and the product comprises ammonia. Embodiment 3 is the method of any of embodiments 1 and 2, wherein the plasmonic nanostructures comprise platinum (Pt), palladium (Pd), ruthenium (Ru), silver (Ag), gold (Au), copper (Cu) or any combination or any alloy thereof. Embodiment 4 is the method of any of embodiments 1 to 3, wherein the catalyst sample further comprises a transition metal or oxide thereof, or lanthanide or oxide thereof V2O5, CuO, Ga203, ImCb, NiO, Sn02, Ce02, M0O3, or WO3, or any combination thereof. Embodiment 5 is the method of any of embodiments 1 to 4, wherein the catalyst sample comprises a promoter, preferably a nanostructure promoter. Embodiment 6 is the method of any of embodiments 1 to 5, further comprising varying testing parameters selected from modifying the size of the plasmonic nanostructures, doping the plasmonic nanostructures, or modifying the reaction conditions such as temperature, pressure, or reactant flow rates, or any combination thereof. Embodiment 7 is the method of any one of embodiments 1 to 6, wherein the plasmonic nanostructures comprise nanorods, nanospheres, nanotubes, or combinations thereof, preferably nanorods. Embodiment 8 is the method of any one of embodiments 1 to 7, wherein the catalyst further includes a support. Embodiment 9 is the method of any of embodiments 1 to 8, wherein the reaction temperature is up to 100 °C. Embodiment 10 is the method of any of embodiments 1 to 9, wherein the reaction temperature is in a range 5 °C to 45 °C.
[0014] Embodiment 1 1 is a testing apparatus for carrying out bench scale tests on a catalyst sample that includes plasmonic nanostructures, the testing apparatus comprising: (a) a gas chamber defined by one or more walls that comprise a wall that is transparent to light, the gas chamber adapted to receive a reactant gas; (b) a liquid chamber defined by one or more walls, the liquid chamber adapted to contain liquid electrolyte; and (c) a working electrode that is adapted to receive the catalyst sample, the working electrode positioned between the gas chamber and the liquid chamber in a manner so that, in operation, the catalyst sample is in contact with gaseous content of the gas chamber, the working electrode being part of an electrochemical cell of the testing apparatus. Embodiment 12 is the testing apparatus of embodiment 11, wherein the working electrode comprises an ion exchange membrane in contact with an electrical conductor. Embodiment 13 is the testing apparatus of embodiment 12, wherein the ion exchange membrane comprises a polymer. Embodiment 14 is the testing apparatus of any of embodiments 12 to 13, further comprising: (a) a counter electrode disposed in the liquid electrolyte; and (b) a reference electrode disposed in the liquid electrolyte, wherein the working electrode, counter electrode, and reference electrode are in electrical communication as part of the electrochemical cell. Embodiment 15 is the testing apparatus of any of embodiments 12 to 14, further comprising: (c) an inlet to the gas chamber adapted for receiving the gas and in fluid communication with an apparatus for measuring an amount of gas flowing through the inlet to the gas chamber; and (d) an outlet from the gas chamber adapted to flowing product away from the gas chamber and in fluid communication with an apparatus for measuring an amount of product flowing through the outlet from the gas chamber. Embodiment 16 is the testing apparatus of any of embodiments 11 to 15, wherein the surface area of the sample is in a range of 0.1 cm2 to 1000 cm2. Embodiment 17 is the testing apparatus of any of embodiments 11 to 16 wherein the weight and/or size of the testing equipment fall into a range of 0.05 kg to 400 kg. Embodiment 18 is the testing apparatus of any of embodiments 11 to 17 wherein the testing apparatus is so adapted that carrying out a test on a first catalyst sample, changing the first catalyst sample to a second catalyst sample, and testing the second catalyst sample takes a period of time in a range of 0.1 h to 100 h. Embodiment 19 is the testing apparatus of any of embodiments 11 to 18, wherein the testing apparatus is configured to test the effectiveness of an electrocatalyst sample and/or photocatalyst sample and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant. Embodiment 20 is a method of testing the effectiveness of a catalyst and/or electrocatalyst sample and/or photocatalyst sample and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant, the method comprising using the testing apparatus of any of embodiments 11 to 19.
[0015] The following includes definitions of various terms and phrases used throughout this specification.
[0016] "Nanostructure" or "nanomaterial" refer to an object or material in which at least one dimension of the object or material is equal to or less than 1000 nm (e.g., one dimension is 1 to 1000 nm in size). In a particular aspect, the nanostructure includes at least two dimensions that are equal to or less than 1000 nm (e.g., a first dimension is 1 to 1000 nm in size and a second dimension is 1 to 1000 nm in size). In another aspect, the nanostructure includes three dimensions that are equal to or less than 100,000 nm (e.g., a first dimension is 1 to 1000 nm in size, a second dimension is 1 to 1000 nm in size, and a third dimension is 1 to 1000 nm in size). The shape of the nanostructure can be of a wire, a particle (e.g., having a substantially spherical shape), a rod, a tetrapod, a hyper-branched structure, a tube, a cube, or mixtures thereof. "Nanoparticles" include particles having an average diameter size of 1 to 1000 nanometers.
[0017] The terms "about" or "approximately" are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment, the terms are defined to be within 10%, preferably, within 5%, more preferably, within 1%, and most preferably, within 0.5%.
[0018] The terms "wt.%", "vol.%" or "mol.%" refers to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or the total moles of material that includes the component. In a non-limiting example, 10 moles of component in 100 moles of the material is 10 mol.% of component.
[0019] The term "substantially" and its variations are defined to include ranges within
10%, within 5%, within 1%, or within 0.5%.
[0020] The terms "inhibiting" or "reducing" or "preventing" or "avoiding" or any variation of these terms, when used in the claims and/or the specification, includes any measurable decrease or complete inhibition to achieve a desired result.
[0021] The term "effective," as that term is used in the specification and/or claims, means adequate to accomplish a desired, expected, or intended result.
[0022] The use of the words "a" or "an" when used in conjunction with the term "comprising," "including," "containing," or "having" in the claims or the specification may mean "one," but it is also consistent with the meaning of "one or more," "at least one," and "one or more than one."
[0023] The words "comprising" (and any form of comprising, such as "comprise" and
"comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes" and "include") or "containing" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps. [0024] The methods and systems of the present invention can "comprise," "consist essentially of," or "consist of particular ingredients, components, compositions, etc., disclosed throughout the specification. With respect to the transitional phrase "consisting essentially of," in one non-limiting aspect, a basic and novel characteristic of the methods and systems of the present invention are their abilities to rapidly analyze catalysts for use in chemical reactions.
[0025] Other objects, features and advantages of the present invention will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments of the invention, are given by way of illustration only and are not meant to be limiting. Additionally, it is contemplated that changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings.
[0027] FIG. 1 shows a gas electrode for testing the effectiveness of a catalyst sample on a reaction that includes a hydrocarbon gas as a reactant according to embodiments of the invention.
[0028] FIG. 2 shows an electrochemical cell, based on polymer electrolyte membrane
(PEM), for testing the effectiveness of a catalyst sample on a reaction that includes a hydrocarbon gas as a reactant according to embodiments of the invention; and [0029] FIG. 3 shows a method for testing the effectiveness of a catalyst sample on a reaction that includes a hydrocarbon gas as a reactant according to embodiments of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Systems and methods have been discovered for screening catalysts for use in chemical processes. The systems and methods utilize plasmonic nanostructures in a screening process that can take place at room temperature. [0031] Embodiments of the invention can include a plasmon enhanced electrochemical route for a chemical process. Such chemical processes may include methane oxidation (e.g., methane to methanol conversion). Incorporating electrochemistry with plasmonic nanostructures, according to embodiments of the invention, can provide additional flexibility in designing materials for methane activation, since the reaction involving methane activation can be controlled at a desired potential so that the kinetics and reaction selectivity can be improved. Moreover, anodic and cathodic half reactions, in embodiments of the invention, occur at separate chambers (electrodes), thus the reaction products can be collected in separate chambers. In the discussion of embodiments of the invention below, methane to methanol conversion will be used as the process in which the embodiments are applied. It should be noted, however, that embodiments of the invention are applicable to other chemical processes.
[0032] Methanol conversion depends on the concentration of methane dissolved into water. One of the challenges to do the electrochemistry for this process is the low solubility of methane in water. [0033] FIG. 1 shows gas electrode 10 for testing the effectiveness of a catalyst sample on a reaction. Gas electrode 10 may be used with a reactive gas (e.g., a hydrocarbon gas as a reactant or gaseous nitrogen). Gas electrode 10, as shown in FIG. 1, is designed to include catalyst 100 deposited on polymer electrolyte membrane 101 (e.g., an ion exchange membrane). Polymer electrolyte membrane 101 and catalyst 100 are in contact with ring 102. Ring 102 can include a metal, for example, a Gold (Au) ring. Catalyst 100 can include plasmonic nanostructures. Plasmonic nanostructures can act either as catalysts themselves, or as promoters to enhance the catalytic reaction. FIG. 2 shows electrochemical cell 20, based on a polymer electrolyte membrane (PEM), for testing the effectiveness of a catalyst sample on a reaction that includes a gaseous reactant (e.g., a hydrocarbon gas as a reactant). According to embodiments of the invention, electrochemical cell 20 may be a testing apparatus for carrying out bench scale tests on a catalyst sample that includes plasmonic nanostructures. Electrochemical cell 20, can include liquid chamber 202, gas chamber 203, and working electrode 200. Liquid chamber 202 can be defined by one or more walls and be adapted to contain liquid electrolyte. Working electrode 200 can be adapted to receive plasmonic nanostructures 210 (e.g., a catalyst sample) on polymer electrolyte membrane 21 1, both of which are in contact with metal ring 212. In other words, the catalyst sample is deposited on working electrode 200. Plasmonic nanostructures 210 can be applied to working electrode 200 either as catalysts or as catalysis promoters. In embodiments of the invention, gas electrode 10 can be working electrode 200 in electrochemical cell 20. Working electrode 200 may be positioned between gas chamber 203 and liquid chamber 202 in a manner so that, in operation, the catalyst sample is in contact with gaseous content of gas chamber 203. Gas chamber 203 can be defined by one or more walls that include a wall that is transparent to light and be adapted to receive a reactant gas. As shown, gas chamber 203 includes a section 201 transparent to light so that light beam 214 can pass through gas chamber 203 and impinge on working electrode 200 and plasmonic nanostructures 210 disposed thereon. In embodiments of the invention, the section of gas chamber 203 that is transparent to light may be a quartz window. [0034] Photocatalysts can be evaluated and developed with electrochemical cell 20. In this way, in embodiments of the invention, electrochemical cell 20 may be a testing apparatus adapted to test the effectiveness of an electrocatalyst and/or photocatalyst and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant.
[0035] As shown in FIG. 2, electrochemical cell 20 may also include counter electrode 206 and/or reference electrode 207, disposed in liquid electrolyte 208. Working electrode 200, counter electrode 206, and reference electrode 207, in embodiments of the invention, are all in electrical communication, as part of electrochemical cell 20.
[0036] Further, electrochemical cell 20, according to embodiments of the invention, includes gas inlet 204 connected to gas chamber 203. Gas inlet 204 leads into gas chamber 203 and is adapted for receiving gas and channeling the gas into gas chamber 203. Further, in embodiments of the invention, electrochemical cell 20 includes gas outlet 205 connected to gas chamber 203. Gas outlet 205 leads from gas chamber 203 and is adapted for flowing product away from gas chamber 203.
[0037] In embodiments of the invention, electrochemical cell 20 includes flow meter 209 for measuring an amount of gas flowing through gas inlet 204 to the gas chamber and flow meter 213 for measuring an amount of product flowing through gas outlet 205 from gas chamber 203.
[0038] In embodiments of the invention, electrochemical cell 20, as a testing apparatus, is of a size and configuration so that it can be used to carry out bench scale tests to determine the effectiveness of catalysts on chemical processes. For example, in embodiments of the invention, electrochemical cell 20 can include a sample with a surface area in a range of 0.1 cm2 to 1000 cm2, and all ranges and values there between including ranges 0.1 cm2 to 25 cm2, 25 cm2 to 50 cm2, 50 cm2 to 75 cm2, 75 cm2 to 100 cm2, 100 cm2 to 125 cm2, 125 cm2 to 150 cm2, 150 cm2 to 175 cm2, 175 cm2 to 200 cm2, 200 cm2 to 225 cm2, 225 cm2 to 250 cm2, 250 cm2 to 275 cm2, 275 cm2 to 300 cm2, 300 cm2 to 325 cm2, 325 cm2 to 350 cm2, 350 cm2 to 375 cm2, 375 cm2 to 400 cm2, 400 cm2 to 425 cm2, 425 cm2 to 450 cm2, 450 cm2 to 475 cm2, 475 cm2 to 500 cm2, 500 cm2 to 525 cm2, 525 cm2 to 550 cm2, 550 cm2 to 575 cm2, 575 cm2 to 600 cm2, 600 cm2 to 625 cm2, 625 cm2 to 650 cm2, 650 cm2 to 675 cm2, 675 cm2 to 700 cm2, 700 cm2 to 725 cm2, 725 cm2 to 750 cm2, 750 cm2 to 775 cm2, 775 cm2 to 800 cm2, 800 cm2 to 825 cm2, 825 cm2 to 850 cm2, 850 cm2 to 875 cm2, 875 cm2 to 900 cm2, 900 cm2 to 925 cm2, 925 cm2 to 950 cm2, 950 cm2 to 975 cm2, and 975 cm2 to 1000 cm2. [0039] Likewise, a bench scale configuration of electrochemical cell 20, according to embodiments of the invention, has a weight in a range of 0.05 kg to 400 kg and/or 0.1 lb to 800 lb, and all ranges and values there between including ranges 0.1 lb to 20 lb, 20 lb to 40 lb, 40 lb to 60 lb, 60 lb to 80 lb, 80 lb to 100 lb, 100 lb to 120 lb, 120 lb to 140 lb, 140 lb to 160 lb, 160 lb to 180 lb, 180 lb to 200 lb, 200 lb to 220 lb, 220 lb to 240 lb, 240 lb to 260 lb, 260 lb to 280 lb, 280 lb to 300 lb, 300 lb to 320 lb, 320 lb to 340 lb, 340 lb to 360 lb, 360 lb to 380 lb, 380 lb to 400 lb, 400 lb to 420 lb, 420 lb to 440 lb, 440 lb to 460 lb, 460 lb to 480 lb, 480 lb to 500 lb, 500 lb to 520 lb, 520 lb to 540 lb, 540 lb to 560 lb, 560 lb to 580 lb, 580 lb to 600 lb, 600 lb to 620 lb, 620 lb to 640 lb, 640 lb to 660 lb, 660 lb to 680 lb, 680 lb to 700 lb, 700 lb to 720 lb, 720 lb to 740 lb, 740 lb to 760 lb, 760 lb to 780 lb, and 780 lb to 800 lb. [0040] Further, as a bench scale testing equipment, according to embodiments of the invention, electrochemical cell 20 may be adapted to carry out tests on catalyst samples much more quickly than if tests were carried out in an industrial setting. For example, in embodiments of the invention, electrochemical cell 20, as a testing apparatus, is so adapted that carrying out a test on a first catalyst sample, changing the first catalyst sample to a second catalyst sample, and testing the second catalyst sample takes a period of time in a range of 0.1 h to 100 h, and all ranges and values there between including ranges 0.1 h to 1 h, 1 h to 5 h, 5 h to 10 h, 10 h to 15 h, 15 h to 20 h, 20 h to 25 h, 25 h to 30 h, 30 h to 35 h, 35 h to 40 h, 40 h to 45 h, 45 h to 50 h, 50 h to 55 h, 55 h to 60 h, 60 h to 65 h, 65 h to 70 h, 70 h to 75 h, 75 h to 80 h, 80 h to 85 h , 85 h to 90 h, 90 h to 95 h, and 95 h to 100 h. [0041] FIG. 3 shows method 30 for testing the effectiveness of a catalyst sample on a reaction that includes a gaseous reactant; according to embodiments of the invention. Method 30 may be implemented by electrochemical cell 20, as a testing apparatus. The gaseous reactant can be any compound that can be gasified. By way of example the gaseous reactant can be an organic compound, nitrogen, carbon dioxide, carbon monoxide, or the like. Organic compounds can include hydrocarbons, heteroatom containing compounds or the like. Hydrocarbons can include compounds having 1 to 20 carbon atoms. Non-limiting examples of hydrocarbons include methane, ethane, ethylene, propane, propenes, butanes, butene, pentanes, pentenes, hexanes, hexenes, heptanes, heptenes, benzene, and the like. Non-limiting example of heteroatom compounds include alcohols, amines, carboxylic acids, nitriles, acetates, thiols, thioethers, heterocyclic compounds, and the like.
[0042] Method 30, as implemented with electrochemical cell 20, may include, at block
300, preparing the catalyst sample to include plasmonic nanostructures 210, which are deposited on polymer electrolyte membrane 21 1 (an electrode membrane). The catalyst sample can be plasmonic nanostructures alone, or in combination with other materials (e.g., support materials, or other catalytic metals). In embodiments of the invention, the plasmonic nanostructures may include platinum (Pt), palladium (Pd), ruthenium (Ru), silver (Ag), gold (Au), copper (Cu) or any combination or any alloy thereof. Further, the catalyst sample can include a transition metal or oxide thereof, a lanthanide or a chalcogenides metal chalcogenides. Transition metals can include one or more metals from Columns 5 to 12 of the Periodic Table. Non-limiting examples of transition metal oxides include V2O5, CuO, Ga203, ImCb, NiO, Sn02, M0O3, or WO3, or any combination thereof. In some embodiments, the catalyst can include a lanthanide (e.g., Ce02, La203, or the like). Non-limiting examples of chalcogenides include sulfides (S), selenides (Se) and the like. Further yet, the catalyst sample may include a promoter, preferably a nanostructure promoter. Promoters can include one or more metals from Columns 1 and 2 of the Periodic Table). Non-limiting examples of promoters include sodium (Na), magnesium (Mg), potassium (K), cesium (Cs), barium (Ba), and the like. The plasmonic nanostructures can have any shape or form. By way of example, the plasmonic nanostructures can be nanorods, nanospheres, nanotubes, or the like. In some embodiments, the plasmonic nanostructures are nanorods. The aspect ratios of the nanorods can be tuned to control the plasmonic effectiveness of the catalyst sample. The plasmonic nanostructures can be deposited on a support to form the catalyst sample. The support can be a metal oxide, a photoactive semiconductor material, or the like. For example, the support can include T1O2, S1O2, AI2O3, TS-1, or the like. In some embodiments, the plasmonic nanostructure can have a core/shell type structure. By way of example, the catalyst can include a plasmonic metal core in a shell structure. Non-limiting examples of core/shell type structures include Au@Ti02, Au@Si02, or the like. [0043] In embodiments of the invention, preparing the catalyst sample may include, for example, applying nanomaterial based catalysts, with or without support, onto the membrane by cost-effective methods like doctor blading, screen printing, spraying, dip-coating and inkjet printing. After the catalyst sample is prepared, method 30, as implemented with electrochemical cell 20, may include, at block 301, positioning working electrode 200, which includes the catalyst sample, between gas chamber 203 and liquid chamber 202 in electrochemical cell 20 in a manner so that the catalyst sample is in contact with gaseous content of gas chamber 203, while working electrode 200 is in electrical communication with counter electrode 206 and reference electrode 207 of electrochemical cell 20. [0044] Method 30, as implemented with electrochemical cell 20, may further include flowing a feed that includes the gaseous reactant into gas chamber 203 and measuring the amount of feed that flows into gas chamber 203, at blocks 302 and 303, respectively.
[0045] At block 304, method 30 involves exposing the plasm onic nanostructures to light for a set period of time sufficient to cause a first half reaction in the gas chamber and a second half reaction in the liquid chamber and thereby cause an overall reaction that forms a product in the gas chamber.
[0046] At block 305, method 30 may include varying testing parameters selected from: modifying the size of the plasmonic nanostructures, doping the plasmonic nanostructures, or modifying the reaction conditions such as temperature, pressure, or reactant flow rates, or any combination thereof. In embodiments of the invention, the reaction temperature is up to 100 °C, and all ranges and values there between including at least, equal to or between any two of 0 °C, 1 °C, 2 °C, 3 °C, 4 °C, 5 °C, 6 °C, 7 °C, 8 °C, 9 °C, 10 °C, 11 °C, 12 °C, 13 °C, 14 °C, 15 °C, 16 °C, 17 °C, 18 °C, 19 °C, 20 °C, 21 °C, 22 °C, 23 °C, 24 °C, 25 °C, 26 °C, 27 °C, 28 °C, 29 °C, 30 °C, 31 °C, 32 °C, 33 °C, 34 °C, 35 °C, 36 °C, 37 °C, 38 °C, 39 °C, 40 °C, 41 °C, 42 °C, 43 °C, 44 °C, 45 °C, 46 °C, 47 °C, 48 °C, 49 °C, 50 °C, 51 °C, 52 °C, 53 °C, 54 °C, 55 °C, 56 °C, 57 °C, 58 °C, 59 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C, and 99.5 °C, preferably less than 60 °C, and more preferably in a range 5 °C to 45 °C. At block 306, method 30 may involve measuring the amount of the product produced and flowed from gas chamber 203 in relation to the amount of the feed flowed out of gas chamber 203. [0047] In embodiments of the invention, electrochemical cell 20 is operated at room temperature procedure, as compared with 60 to 120 °C for current state of the art electrochemical cells. In embodiments of the invention, methane/water vapor stream is fed as input in gas chamber 203 through gas inlet 204. Quartz window of gas chamber 203 allows a light path needed for plasmonic nanostructures 210.
[0048] A platform with significant advantage for working electrode 200 acts as the catalytic site, and a half-reaction proceeds on working electrode 200 as reaction (1) on the catalyst at a desired potential for conversion of the gaseous reactant to the product. By way of example, gaseous methane to methanol conversion. The generated protons can transfer through polymer electrolyte membrane 21 1 (for instance, Nafion®) to participate in a hydrogen evolution reaction (HER) at counter electrode 206, which is immersed into electrolyte in liquid chamber 202, as reaction (2). CH4 + H2O→ CH3OH + 2H+ + 2e" (1)
2H+ + 2e → H2 (2)
Overall reaction is:
CH4 + H2O→ CH3OH + H2 AG°298K = 1 17 kJ/mol (3)
[0049] In another example, screening of catalysts for ammonia synthesis can be performed using the electrochemical cell 20. Gaseous nitrogen can be reduced in the gaseous chamber upon contact with the plasmonic nanostructure, while the liquid chamber can be used for the oxidation reaction (e.g., water splitting). The overall reaction using water in the liquid chamber is shown in equation (4)
N2 + 3H20→ 2 H3 + 1.502 (4) [0050] The design of electrochemical cell 20 favors the mass transfer of gaseous reactants (e.g., methane or nitrogen) in gas chamber 203, and avoids any possible impurities in the solution (liquid chamber 202) that may affect the selectivity and stability of the catalysts. Another advantage of the design is that the existing catalysts for a process and those under development can be directly applied on working electrode 200, which provides a direct comparison.
[0051] Although embodiments of the present invention have been described with reference to blocks of FIG. 3, it should be appreciated that operation of the present invention is not limited to the particular blocks and/or the particular order of the blocks illustrated in FIG. 3. Accordingly, embodiments of the invention may provide functionality as described herein using various blocks in a sequence different than that of FIG. 3. [0052] Although embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the above disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

A method of testing the effectiveness of a catalyst sample on a gaseous reactant, the method comprising:
(a) preparing the catalyst sample to include plasmonic nanostructures deposited on an electrode membrane;
(b) positioning a working electrode that includes the catalyst sample between a gas chamber and a liquid chamber in an electrochemical cell in a manner so that the catalyst sample is in contact with gaseous content of the gas chamber, the working electrode is in electrical communication with a counter electrode and a reference electrode of the electrochemical cell;
(c) flowing a feed that includes the gaseous reactant into the gas chamber;
(d) measuring the amount of feed that flows into the gas chamber;
(e) exposing the plasmonic nanostructures to light for a set period of time sufficient to cause a first half reaction in the gas chamber and a second half reaction in the liquid chamber and thereby cause an overall reaction that forms a product in the gas chamber; and
(f) measuring the amount of the product in relation to the amount of the feed flowed out of the gas chamber.
The method of claim 1, wherein the gaseous reactant comprises a gaseous hydrocarbon and the product comprises an alcohol, or gaseous nitrogen and the product comprises ammonia.
The method of claim 1, wherein the plasmonic nanostructures comprise platinum (Pt), palladium (Pd), ruthenium (Ru), silver (Ag), gold (Au), copper (Cu) or any combination or any alloy thereof.
The method of claim 1, wherein the catalyst sample further comprises a transition metal or oxide thereof, or lanthanide or oxide thereof V2O5, CuO, Ga203, ln203, NiO, Sn02, Ce02, M0O3, or W03, or any combination thereof.
The method of claim 1, wherein the catalyst sample further comprises a promoter.
The method of claim 1, further comprising varying testing parameters selected from modifying the size of the plasmonic nanostructures, doping the plasmonic nanostructures, or modifying the reaction conditions, wherein the reaction conditions comprise temperature, pressure, or reactant flow rates, or any combination thereof.
7. The method of claim 1, wherein the plasmonic nano structures comprise nanorods, nanospheres, nanotubes, or combinations thereof.
8 The method of claim 1, wherein the catalyst sample further includes a support.
9. The method of claim 1, wherein the reaction temperature is up to 100 °C.
The method of claim 1, wherein the reaction temperature is in a range 5 °C to 45 °C.
A testing apparatus for carrying out bench scale tests on a catalyst sample comprising plasmonic nanostructures, the testing apparatus comprising:
(a) a gas chamber defined by one or more walls that comprise a wall that is transparent to light, the gas chamber adapted to receive a reactant gas;
(b) a liquid chamber defined by one or more walls, the liquid chamber adapted to contain liquid electrolyte; and
(c) a working electrode that is adapted to receive the catalyst sample, the working electrode positioned between the gas chamber and the liquid chamber in a manner so that, in operation, the catalyst sample is in contact with gaseous content of the gas chamber, the working electrode being part of an electrochemical cell of the testing apparatus.
The testing apparatus of claim 11, wherein the working electrode comprises an ion exchange membrane in contact with an electrical conductor.
The testing apparatus of claim 12, wherein the ion exchange membrane comprises a polymer.
The testing apparatus of claim 12, further comprising:
(a) a counter electrode disposed in the liquid electrolyte; and
(b) a reference electrode disposed in the liquid electrolyte, wherein the working electrode, counter electrode, and reference electrode are in electrical communication as part of the electrochemical cell.
The testing apparatus of claim 14, further comprising:
(c) an inlet to the gas chamber adapted for receiving the gas and in fluid communication with an apparatus for measuring an amount of gas flowing through the inlet to the gas chamber; and (d) an outlet from the gas chamber adapted to flowing product away from the gas chamber and in fluid communication with an apparatus for measuring an amount of product flowing through the outlet from the gas chamber
16. The testing apparatus of claim 11, wherein the surface area of the catalyst sample is in a range of 0.1 cm2 to 1000 cm2.
17. The testing apparatus of claim 11 wherein the weight and/or size of the testing equipment fall into a range of 0.05 kg to 400 kg.
18. The testing apparatus of claim 11, wherein the testing apparatus is adapted to carry out a test on a first catalyst sample, change the first catalyst sample to a second catalyst sample, and test the second catalyst sample in a period of time ranging from 0.1 h to 100 h.
19. The testing apparatus of claim 11, wherein the testing apparatus tests effectiveness of an electrocatalyst sample and/or photocatalyst sample and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant.
20. A method of testing the effectiveness of a catalyst and/or electrocatalyst sample and/or photocatalyst sample and/or photoelectrochemical catalyst sample for a reaction that includes a gas as a reactant, the method comprising using the testing apparatus of claim 11.
PCT/US2018/013493 2017-01-23 2018-01-12 Electrochemical apparatus and its use for screening of nanostructure catalysts WO2018136323A1 (en)

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