CN107421992B - method for detecting ozone and ozone precursor - Google Patents
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Abstract
The invention relates to a method for detecting ozone and an ozone precursor. A method for detecting ozone and an ozone precursor comprises the following steps: (1) completely dissolving ammonium molybdate, thiourea and zinc acetate in water to obtain a mixed solution; (2) preparing the mixed solution into p-type molybdenum disulfide nanosheet powder; (3) repeating the steps (1) and (2) for not less than 4 times, wherein the molar ratio of ammonium molybdate to zinc acetate is different each time, so as to obtain not less than 5 types of p-type molybdenum disulfide nanosheet powder with different zinc ion doping amounts; (4) respectively preparing not less than 5 kinds of molybdenum disulfide nanosheet powder with different zinc ion doping amounts into sensors, and constructing a sensor array; (5) and respectively detecting the ozone and the ozone precursor by using a sensor array, and collecting response signals of the sensor array to the ozone and the ozone precursor. The detection method of the ozone and the ozone precursor has the advantages of low working temperature, good recognition of the ozone and the ozone precursor and short response time.
Description
Technical Field
the invention belongs to the technical field of gas-sensitive sensing detection, and particularly relates to a detection method of ozone and an ozone precursor.
background
Ozone reacts with almost any biological tissue and is very damaging to human health. Ozone is also associated with other pollutants. For example, ozone can increase the harm of respirable Particulate Matter (PM) to humans, and PM can also increase the harm of ozone. More and more studies have demonstrated that even with relatively low ozone concentrations, the resulting hazard is equally severe if exposed for extended periods (6-8 hours). The U.S. environmental protection agency specifies that the average concentration of ozone in an atmospheric environment for 8 hours cannot exceed 80ppb (Ebeling, D., et al., Electrochemical zone sensor And insulation with the characteristics of the electrode And gas flow efficiencies, 2009.137(1): p.129-133; 3.Policy, E.S.P., Policy analysis scientific And Technical Information-Review of the National environmental index Standards (NAAQS) for ozone, EPAHQ-OAR-2008-8-. The state of California states that Air purification equipment manufacturers produce indoor Air purification equipment that should control the indoor ozone concentration to a level that cannot exceed 50ppb (California Environmental Protection Agency, Air resources Board AB 2276 Air Cleaner Regulation, 2007). Concentration of ozoneThe rise in (1) is a result of the combined action of motor vehicle exhaust emissions, chemical processes and meteorological conditions. The vast majority of ozone comes from small natural sources and large man-made sources (nitrogen oxides NO)Xand Volatile Organic Compounds (VOC)S) The concentration of secondary pollutants generated through a series of photochemical reactions under the condition of illumination is closely related to the meteorological condition. The reaction is most severe under conditions of high temperature, strong sunlight, low humidity and calm wind, with ultraviolet radiation being the most critical factor. Therefore, the problem of ozone pollution in summer in northern China is increasingly prominent.
the high sensitivity and high selectivity detection of ozone and its precursor are the technical premise and foundation of ozone pollution control. In recent years, in most cities, ozone pollution exceeds PM2.5 in summer, and becomes a primary pollutant, and under the background, the ozone pollution detection and control method has more significance on effective detection and control of ozone. However, the high sensitivity and high selectivity detection of ozone is still a challenging scientific problem due to its high oxidation, instability (half-life of ozone in water and air is typically only 5-15 minutes), and the presence and interference of various other pollutants in the air. At present, the common methods for ozone detection mainly comprise: iodometry, spectrophotometry, electrochemistry, fluorescence, and the like. The ultraviolet spectroscopy is widely researched and applied because the ozone detection mechanism is clear, the technology is mature, and the detection performance is stable and reliable. However, the uv spectroscopy has the disadvantages of large size, high cost, and single detection function, and its practical application range is limited.
in order to meet the effective detection of ozone and precursors thereof, the development of an ozone sensor with low cost, small volume, good stability, high sensitivity and good anti-interference performance is urgently needed. The metal oxide gas sensor has the advantages of small volume, high sensitivity, convenience in integration and convenience in use, shows great potential in ozone detection, and develops very rapidly in recent years. However, generally, the metal oxide semiconductor gas sensor has poor selectivity, long response time (generally several minutes), high operating temperature (200-. In addition, the higher working temperature can cause thermal degradation of ozone, thereby affecting the detection performance of the gas sensor, and causing the poor detection effect of the detection method using the metal oxide gas sensor. The metal sulfide semiconductor has low surface state density, is very sensitive to the change of surface electrical property, and has the potential of being used as a high-sensitive resistance type gas sensitive material.
In view of the above, it is necessary to provide a method for detecting ozone and an ozone precursor by using a sensor made of molybdenum disulfide nanosheets.
disclosure of Invention
the invention aims to provide a method for detecting ozone and an ozone precursor, which combines doping modified ultrathin molybdenum disulfide nanosheets with subsequent sensing data processing to realize sensitive and rapid identification and detection of the ozone and the ozone precursor at room temperature and has the advantages of low working temperature, good selectivity to the ozone and the ozone precursor and short response time.
In order to achieve the purpose, the scheme adopted by the invention is as follows:
A method for detecting ozone and an ozone precursor comprises the following steps:
(1) Completely dissolving ammonium molybdate, thiourea and zinc acetate in water to obtain a mixed solution; the molar ratio of thiourea to ammonium molybdate to zinc acetate is 3000:100: 0-15;
(2) Transferring the mixed solution into a sealed reaction kettle, reacting at the temperature of 170-190 ℃ for 22-26 hours, naturally cooling to room temperature, and performing centrifugal separation to obtain black precipitate;
washing the precipitate with water or anhydrous ethanol until the solution is neutral to obtain washed precipitate; the washing refers to ultrasonically dispersing the precipitate in water or absolute ethyl alcohol, then carrying out centrifugal separation, removing supernatant, and separating to obtain precipitate;
Drying the washed precipitate at 50-70 deg.C for 6-12 hr to obtain dried precipitate; fully grinding the dried precipitate to obtain p-type molybdenum disulfide nanosheet powder;
(3) Repeating the steps (1) and (2) for not less than 4 times, wherein the molar ratio of ammonium molybdate to zinc acetate is different each time and is different from the molar ratio of ammonium molybdate to zinc acetate in the step (1), so as to obtain not less than 5 types of p-type molybdenum disulfide nanosheet powder with different zinc ion doping amounts;
(4) Respectively preparing at least 5 types of p-type molybdenum disulfide nanosheet powder with different zinc ion doping amounts into sensors, and constructing a sensor array consisting of at least 5 sensors;
(5) And respectively detecting the ozone and the ozone precursor by using a sensor array, and collecting response signals of the sensor array to the ozone and the ozone precursor.
Further, in the step (1), ammonium molybdate, thiourea and zinc acetate are added into water and dissolved by means of magnetic stirring.
further, in the step (2), after cooling to room temperature, the rotation speed of centrifugal separation is 8000-;
The washing times are 3-5 times;
The thickness of the p-type molybdenum disulfide nanosheet powder is 3-20 nm.
Still further, the washing in step (2): the rotation speed of the centrifugal separation is 8000-12000r/min, and the time is 3-5 minutes.
Further, in the step (2), the reaction temperature is 180 ℃, and the reaction time is 24 hours;
the drying temperature was 60 ℃.
further, in the step (3), the detection temperature is 20-30 ℃, and the relative humidity is 15-25%.
still further, the water is deionized water.
compared with the prior art, the invention has the beneficial effects that:
compared with the prior art, the detection method of the ozone and the ozone precursor has the advantages of low working temperature, good selectivity to the ozone and the ozone precursor and short response time. According to the detection method, the electron depletion layer of the molybdenum disulfide nanosheet is regulated and controlled by controlling the doping amount of zinc ions in the molybdenum disulfide, so that the advantage of large surface area of the molybdenum disulfide nanosheet is combined with the surface state of a zinc ion doping regulation and control sensing material under the condition that the morphology of the molybdenum disulfide nanosheet is kept unchanged, a portable, economical and low-power-consumption gas sensor array is further constructed, and rapid identification and detection of ozone, nitrogen dioxide, ethanol and formaldehyde at room temperature are realized. Meanwhile, the relationship between the structure and the composition of the metal sulfide sensing material and the sensing performance is disclosed.
Drawings
fig. 1 is an XRD pattern of ultra-thin molybdenum disulfide nanosheets with zinc ion doping levels of 0%, 1%, 3%, 5%, 9% and 15% in example 1 of the present invention;
FIG. 2 is a TEM image of an ultrathin Mo disulfide nanosheet with a Zn ion doping amount of 0% in step (1) of example 1 of the present invention;
FIG. 3 is a TEM image of an ultrathin Mo disulfide nanosheet with a doping amount of 1% Zn ion in step (2) in example 1 of the present invention;
FIG. 4 is a TEM image of an ultrathin Mo disulfide nanosheet with a Zn ion doping amount of 3% in step (3) of example 1 of the present invention;
FIG. 5 is a TEM image of an ultrathin Mo disulfide nanosheet with a Zn ion doping amount of 5% in step (4) of example 1 of the present invention;
FIG. 6 is a TEM image of an ultrathin Mo disulfide nanosheet with a doping amount of 9% Zn ion in step (5) in example 1 of the present invention;
Fig. 7 is a transmission electron microscope image of an ultrathin molybdenum disulfide nanosheet with a 15% doped zinc ion in step (6) of example 1 of the present invention;
fig. 8 is a response curve diagram of six-graded ultrathin molybdenum disulfide nanosheets to formaldehyde at room temperature in example 1 of the present invention;
Fig. 9 is a response curve diagram of six-graded ultra-thin molybdenum disulfide nanosheets to ethanol at room temperature in example 1 of the present invention;
fig. 10 is a graph showing the response of six-graded ultra-thin molybdenum disulfide nanosheets to nitrogen dioxide at room temperature in example 1 of the present invention;
fig. 11 is a response curve diagram of six-graded ultra-thin molybdenum disulfide nanosheets to ozone at room temperature in example 1 of the present invention;
fig. 12 is a graph showing a comparison of response of an ozone sensor array made of ultrathin molybdenum disulfide nanosheets having zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9% and 15% respectively to formaldehyde in example 1 of the present invention;
Fig. 13 is a graph comparing response of an ozone sensor array made of ultrathin molybdenum disulfide nanosheets with zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9% and 15% in example 1 of the present invention to ethanol.
Fig. 14 is a graph comparing the response of the ozone sensor array made of the ultrathin molybdenum disulfide nanosheets with the zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9% and 15% in example 1 of the present invention to ozone;
fig. 15 is a graph comparing the response of the ozone sensor array made of the ultrathin molybdenum disulfide nanosheets with zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9% and 15% in example 1 of the present invention to nitrogen dioxide.
Detailed Description
in order to further illustrate the method for detecting ozone and ozone precursor of the present invention and achieve the desired objects, the following embodiments are provided to describe the method for detecting ozone and ozone precursor according to the present invention, and the detailed description thereof, the structure, the features and the efficacy thereof. In the following description, different "one embodiment" or "an embodiment" refers to not necessarily the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
Before describing in detail the method for detecting ozone and ozone precursor of the present invention, it is necessary to further describe the materials and methods mentioned in the present invention to achieve better results.
The principle of the invention is as follows: the zinc ion-doped molybdenum disulfide nanosheets are prepared by a hydrothermal synthesis method, namely, the zinc ion-doped ultrathin molybdenum disulfide nanosheets with different concentrations are prepared by a mixed solution composed of ammonium molybdate, thiourea, zinc acetate and water, the advantage of large specific surface area of a sheet-shaped structure nano material is combined with a zinc ion-doped molybdenum disulfide electron depletion layer for regulating and controlling, so that the gas-sensitive performance of the molybdenum disulfide nanosheets is improved, differential sensing signals are generated for ozone at room temperature, the molybdenum disulfide nanosheets with different zinc ion doping concentrations are constructed into a sensor array, and finally, kinetic parameters (response magnitude) and thermodynamic parameters (response time) in sensing signals of the sensor array are extracted and used as fingerprint parameters of different analytes, so that the effect of identifying and detecting the ozone and ozone precursor is achieved.
Molybdenum disulfide, chemical formula: MoS2Relative molecular mass: 160.07 black solid powder with metallic luster. Has a chemical formula of MoS2Melting point 1185 ℃ and density 4.80g/cm3(14 ℃) and at 450 ℃ sublimation begins, which is soluble in aqua regia and hot concentrated sulfuric acid and insoluble in water and dilute acid.
the raw materials adopted by the invention are as follows:
Ammonium molybdate, also known as: special ammonium molybdate, (T-4) -ammonium molybdate, ammonium tetramolybdate and diammonium molybdate, wherein the ammonium molybdate is white or light green crystal with molecular formula of H8MoN2O4Molecular weight of 196.0145, density of (g/mL,25/4 ℃)3.1, melting point of 300 ℃, easy purification, easy dissolution, easy thermal dissociation, and thermally dissociated NH3The gas can escape fully along with heating, and the molybdenum product is not polluted any more.
thiourea and Chinese alias thiourea with molecular formula of CH4N2s, white and glossy crystal with molecular weight of 76.12, bitter taste, density of 1.41, melting point of 176-. Partially isomerizes upon melting to form thiocyanato-ammonium.
zinc acetate, chinese alias: zinc acetate with molecular formula Zn (CH)3COO)2molecular weight is 183.48, it is glossy hexahedral flake or plate crystal, has acetic acid smell, and is obtained by reacting zinc oxide with acetic acid.
with the knowledge of the relevant materials and methods mentioned in the present invention, a method for detecting ozone and ozone precursors according to the present invention will be described in further detail below with reference to specific examples:
example 1.
(1) a: 0.1960g of ammonium molybdate and 2.2836g of thiourea are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 30 minutes, and solutes are completely dissolved to form a uniform solution, so that a mixed solution 1 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 180 ℃ for reaction for 24 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 10000r/min for 4 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 3 times until the solution is neutral to obtain washed precipitate; the washing is to ultrasonically disperse the precipitate in deionized water, then centrifugally separate the precipitate at 12000r/min for 3 minutes, remove the supernatant and separate the precipitate to obtain the precipitate;
transferring the washed precipitate into a 100ml beaker, drying for 8 hours in an oven at the temperature of 60 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 0%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm; as shown in fig. 2, it can be seen that the ultra-thin molybdenum disulfide nanosheet powder with 0% of zinc ion doping amount is a two-dimensional sheet structure;
(2) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0018g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 30 minutes, and solute is completely dissolved to form uniform solution, so that mixed solution 2 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0018 ÷ 183.48 ≈ 9.81 × 10-6mol ≈ 9.81 × 10-3mmol ≈ 0.01mmol)
b: transferring the mixed solution 2 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 180 ℃ for reaction for 24 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 8000r/min for 5 minutes to obtain black molybdenum disulfide precipitate;
Washing the precipitate with deionized water for 4 times until the solution is neutral to obtain washed precipitate; the washing is to ultrasonically disperse the precipitate in deionized water, then centrifugally separate the precipitate at 8000r/min for 5 minutes, remove the supernatant and separate the precipitate to obtain the precipitate;
Transferring the washed precipitate into a 100ml beaker, drying for 8 hours in an oven at the temperature of 60 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 1%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm; as shown in fig. 3, it can be seen that the ultra-thin molybdenum disulfide nanosheet powder with a zinc ion doping amount of 1% is a two-dimensional sheet-like structure;
(3) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0055g of zinc acetate are added into a beaker containing 35 ml of deionized water, and the mixture is magnetically stirred for 30 minutes, so that the solute is completely dissolved to form a uniform solution, and a mixed solution 3 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0055 ÷ 183.48 ≈ 2.997 × 10-5mol ≈ 2.997 × 10-2mmol ≈ 0.03mmol)
b: transferring the mixed solution 3 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 180 ℃ for reaction for 24 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 10000r/min for 4 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 5 times until the solution is neutral to obtain washed precipitate; the washing refers to ultrasonically dispersing the precipitate in deionized water, then carrying out centrifugal separation at a rotating speed of 9000r/min for 4 minutes, removing supernatant, and separating to obtain precipitate;
Transferring the washed precipitate into a 100ml beaker, drying for 6 hours in an oven at the temperature of 60 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 3%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm; as shown in fig. 4, it can be seen that the ultra-thin molybdenum disulfide nanosheet powder with a zinc ion doping amount of 3% is a two-dimensional sheet-like structure;
(4) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0092g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 30 minutes, and solutes are completely dissolved to form a uniform solution, so that a mixed solution 4 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0092 ÷ 183.48 ≈ 5.0141 × 10-5mol ≈ 5.0141 × 10-2mmol ≈ 0.05mmol)
b: transferring the mixed solution 4 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 180 ℃ for reaction for 24 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 10000r/min for 5 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 3 times until the solution is neutral to obtain washed precipitate; the washing is to ultrasonically disperse the precipitate in deionized water, then centrifugally separate the precipitate at the rotating speed of 12000r/min for 5 minutes, remove the supernatant and separate the precipitate to obtain the precipitate;
Transferring the washed precipitate into a 100ml beaker, drying for 12 hours in an oven at the temperature of 60 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 5%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm; as shown in fig. 5, it can be seen that the ultra-thin molybdenum disulfide nanosheet powder with a zinc ion doping amount of 5% is a two-dimensional sheet-like structure;
(5) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0165g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 30 minutes, and solute is completely dissolved to form uniform solution, so that mixed solution 5 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0165 ÷ 183.48 ≈ 8.992 × 10-5mol ≈ 8.992 × 10-2 ≈ 0.09mmol)
b: transferring the mixed solution 5 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 180 ℃ for reaction for 24 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 11000r/min for 4 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 3 times until the solution is neutral to obtain washed precipitate; the washing refers to ultrasonically dispersing the precipitate in deionized water, then carrying out centrifugal separation at a rotating speed of 9000r/min for 3 minutes, removing supernatant, and separating to obtain precipitate;
transferring the washed precipitate into a 100ml beaker, drying for 9 hours in an oven at the temperature of 60 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 9%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm; as shown in fig. 6, it can be seen that the ultra-thin molybdenum disulfide nanosheet powder with a zinc ion doping amount of 9% has a two-dimensional sheet structure;
(6) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0275g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 30 minutes, and the solute is completely dissolved to form a uniform solution, so that a mixed solution 6 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0275 ÷ 183.48 ≈ 0.1498 × 10-3mol ≈ 0.1498mmol ≈ 0.15mmol)
b: transferring the mixed solution 6 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 180 ℃ for reaction for 24 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 10000r/min for 3 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 5 times until the solution is neutral to obtain washed precipitate; the washing is to ultrasonically disperse the precipitate in deionized water, then centrifugally separate the precipitate at 8000r/min for 3 minutes, remove the supernatant and separate the precipitate to obtain the precipitate;
transferring the washed precipitate into a 100ml beaker, drying for 10 hours in an oven at the temperature of 60 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 15%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm; as shown in fig. 7, it can be seen that the ultra-thin molybdenum disulfide nanosheet powder with 15% of zinc ion doping amount is a two-dimensional sheet structure;
(7) preparing a sensor:
a: respectively putting 0.1g of the ultrathin molybdenum disulfide nanosheet powder with the zinc ion doping amounts of 0%, 1%, 3%, 5%, 9% and 15% prepared in the steps (1) - (6) into an agate mortar, respectively adding 3-5 drops of deionized water, and grinding into paste;
b: respectively coating the samples obtained in the step (7) a on electrode sheets of 6 comb-shaped electrodes by using a fine writing brush to form a sensor array consisting of ultrathin molybdenum disulfide nanosheet powder with the zinc ion doping amount of 0%, the zinc ion doping amount of 1%, the zinc ion doping amount of 3%, the zinc ion doping amount of 5%, the zinc ion doping amount of 9% and the zinc ion doping amount of 15%;
(8) And (3) testing the response curve of the sensor array consisting of 6 sensors to ozone, an ozone precursor and volatile organic compounds (formaldehyde and ethanol) prepared in the step (7) by using a Catherine electric meter, collecting the response signals of the sensor array to the ozone and the ozone precursor, extracting the kinetic parameter response size and the thermodynamic parameter response time in the sensing signals, respectively calculating the ratio of the response size of each sensor in the sensor array to four analytes to the response time, and taking the ratio as the fingerprint parameters of different analytes.
detection of saturated vapors of formaldehyde:
The power supply of the electrochemical workstation is switched on, the response curve of the sensor array (the test temperature is 25 ℃, the relative humidity is 20%) to the saturated vapor of formaldehyde is tested under the bias voltage of 1V, and the response sizes of 0%, 1%, 3%, 5%, 9% and 15% of the ultrathin molybdenum disulfide nanosheets to formaldehyde respectively reach-2.94%, -3.23%, -5.95%, -7.73%, -4.27%, -2.90%; the response time is 2.87 seconds, 2.10 seconds, 3.38 seconds, 9.10 seconds, 4.55 seconds and 3.16 seconds respectively (as shown in fig. 8, the doping concentration of zinc ions from left to right corresponds to 0%, 1%, 3%, 5%, 9% and 15% of the ultrathin molybdenum disulfide nanosheet respectively, and it can be simultaneously shown that the prepared molybdenum disulfide is a p-type semiconductor and is hole-conducting).
detection of saturated vapors of ethanol:
The electrochemical workstation power supply is switched on, under the bias voltage of 1V, the response curve of the sensor array (the test temperature is 22 ℃, and the relative humidity is 20%) to the saturated vapor of the ethanol is tested, and as can be seen from the response curve, the response sizes of 0%, 1%, 3%, 5%, 9% and 15% of the ultrathin molybdenum disulfide nanosheets to the ethanol respectively reach-3.54%, -4.34%, -6.40%, -10.27%, -6.84%, -4.41% at room temperature; the response time is 2.02 seconds, 1.70 seconds, 2.20 seconds, 4.44 seconds, 5.71 seconds and 3.82 seconds respectively (as shown in fig. 9, the doping concentration of zinc ions from left to right corresponds to 0%, 1%, 3%, 5%, 9% and 15% of the ultrathin molybdenum disulfide nanosheet, and it can be simultaneously shown that the prepared molybdenum disulfide is a p-type semiconductor and is hole-conducting).
detection of nitrogen dioxide:
switching on an electrochemical workstation power supply, and testing the NO of the sensor prepared by 0%, 1%, 3%, 5%, 9% and 15% of ultrathin molybdenum disulfide nanosheets (the test temperature is 25 ℃, and the relative humidity is 20%) under the bias of 1V2the response of the ultrathin molybdenum disulfide nanosheet to nitrogen dioxide respectively reaches-2.26%, -4.41%, -5.33%, -7%, -4.46%, -2.96%; the response time is 1.13 seconds, 0.91 seconds, 1.57 seconds, 1.70 seconds and 2.42 seconds respectively (as shown in fig. 10, the doping concentration of zinc ions from left to right corresponds to 0%, 1%, 3%, 5%, 9% and 15% of the ultrathin molybdenum disulfide nanosheet, and it can be simultaneously shown that the prepared molybdenum disulfide is a p-type semiconductor and is hole-conducting).
detection of ozone:
switching on a power supply of an electrochemical workstation, testing a response curve of sensors (the test temperature is 25 ℃, and the relative humidity is 20%) prepared from 0%, 1%, 3%, 5%, 9% and 15% of ultrathin molybdenum disulfide nanosheets in saturated vapor of ozone under the bias voltage of 1V, wherein the response sizes of 0%, 1%, 3%, 5%, 9% and 15% of ultrathin molybdenum disulfide nanosheets to ozone respectively reach 1.70%, 2.28%, 3.38%, 6.48%, 3.71% and 2.81% at room temperature as can be seen from the response curve; the response time is 5.48 seconds, 4.53 seconds, 7.26 seconds, 11.83 seconds, 8.89 seconds and 3.18 seconds respectively (as shown in fig. 11, the doping concentration of zinc ions from left to right corresponds to 0%, 1%, 3%, 5%, 9% and 15% of the ultrathin molybdenum disulfide nanosheet, and it can be also shown that the prepared molybdenum disulfide is a p-type semiconductor and is hole-conducting).
as shown in an XRD characterization chart of fig. 1, no significant peak appears in the ultra-thin molybdenum disulfide nanosheets with zinc ion doping amounts of 0%, 1%, 3%, 5%, 9% and 15%, indicating that the morphology of the molybdenum disulfide nanosheet is unchanged.
As shown in fig. 12, the response contrast graph of the sensor array made of the ultrathin molybdenum disulfide nanosheets with the zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9% and 15% respectively to formaldehyde is shown, that is, the characteristic fingerprint of the sensor array made of the ultrathin molybdenum disulfide nanosheets with the zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9% and 15% respectively to formaldehyde. The difference of 6 sensors is shown, and the sensor array has selectivity, so that the formaldehyde gas can be effectively detected and identified.
as shown in fig. 13, the response comparison graph of the sensor array made of the ultrathin molybdenum disulfide nanosheets with the zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9% and 15% respectively to ethanol is shown, that is, the characteristic fingerprint of the sensor array made of the ultrathin molybdenum disulfide nanosheets with the zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9% and 15% respectively to ethanol. The difference of 6 sensors is shown, and the sensor array has selectivity, so that the ethanol gas can be effectively detected and identified.
as shown in fig. 14, a response comparison graph of the sensor array made of the ultrathin molybdenum disulfide nanosheets with the zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9% and 15% respectively to ozone is shown, that is, the characteristic fingerprint of the sensor array made of the ultrathin molybdenum disulfide nanosheets with the zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9% and 15% respectively to ozone is shown. 6 sensors have differences, and the sensor array has selectivity, so that ozone can be effectively detected and identified.
As shown in fig. 15, the graph is a comparison graph of response of the sensor array made of the ultrathin molybdenum disulfide nanosheets with zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9%, and 15% to nitrogen dioxide, that is, the characteristic fingerprint of the sensor array made of the ultrathin molybdenum disulfide nanosheets with zinc ion doping concentrations of 0%, 1%, 3%, 5%, 9%, and 15% to nitrogen dioxide. The difference of 6 sensors is shown, and the sensor array has selectivity, so that the nitrogen dioxide can be effectively detected and identified.
The detection method of the ozone and the ozone precursor provided by the embodiment of the invention has the advantages of low working temperature, good selectivity to the ozone and the ozone precursor, short response time within 1 minute. According to the detection method, the electron depletion layer of the molybdenum disulfide nanosheet is regulated and controlled by controlling the doping amount of zinc ions in the molybdenum disulfide, so that the advantage of large surface area of the molybdenum disulfide nanosheet is combined with the surface state of a zinc ion doping regulation sensing material under the condition that the morphology of the molybdenum disulfide nanosheet is kept unchanged, a gas-sensitive sensor array consisting of 6 sensors is further constructed, and rapid identification and detection of ozone, nitrogen dioxide, ethanol and formaldehyde at room temperature are realized.
Example 2.
(1) a: 0.1960g of ammonium molybdate and 2.2836g of thiourea are added into a beaker with 35 ml of deionized water, magnetic stirring is carried out for 25 minutes, and solute is completely dissolved to form uniform solution, so as to obtain mixed solution 1; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 170 ℃ for reaction for 26 hours, and after the reaction kettle is naturally cooled to room temperature, carrying out centrifugal separation at the rotating speed of 8000r/min for 5 minutes to obtain black molybdenum disulfide precipitate;
Washing the precipitate with anhydrous ethanol for 3 times until the solution is neutral to obtain washed precipitate; the washing refers to completely dispersing the precipitate in absolute ethyl alcohol by ultrasound, then carrying out centrifugal separation at the rotating speed of 12000r/min for 5 minutes, removing supernatant, and separating to obtain precipitate;
transferring the washed precipitate into a 100ml beaker, drying in an oven at 50 ℃ for 6 hours, and fully grinding with an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 0%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(2) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0073g of zinc acetate are added into a beaker containing 35 ml of deionized water, and the mixture is magnetically stirred for 28 minutes until the solute is completely dissolved to form a uniform solution, so that a mixed solution 2 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0073 ÷ 183.48 ≈ 3.978 × 10-6mol ≈ 3.978 × 10-3mmol ≈ 0.04mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 175 ℃ for reaction for 23 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 8000r/min for 4 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with anhydrous ethanol for 4 times until the solution is neutral to obtain washed precipitate; the washing is to completely disperse the precipitate in absolute ethyl alcohol by ultrasound, then carry out centrifugal separation at the rotating speed of 8000r/min for 3 minutes, remove the supernatant and separate to obtain the precipitate;
Transferring the washed precipitate into a 100ml beaker, drying for 8 hours in an oven at the temperature of 55 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 4%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(3) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0147g of zinc acetate are added into a beaker containing 35 ml of deionized water, and the mixture is magnetically stirred for 29 minutes until the solute is completely dissolved to form a uniform solution, so that a mixed solution 3 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0147 ÷ 183.48 ≈ 0.8011 × 10-4mol ≈ 0.0801mmol ≈ 0.08mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a blowing drying oven with the temperature of 182 ℃ for reaction for 23.5 hours, and after the reaction kettle is naturally cooled to room temperature, carrying out centrifugal separation at the rotating speed of 11000r/min for 3 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with anhydrous ethanol for 5 times until the solution is neutral to obtain washed precipitate; the washing is to completely disperse the precipitate in absolute ethyl alcohol by ultrasound, then carry out centrifugal separation at the rotating speed of 8000r/min for 3 minutes, remove the supernatant and separate to obtain the precipitate;
Transferring the washed precipitate into a 100ml beaker, drying for 7 hours in an oven at the temperature of 60 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 8%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(4) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0220g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 31 minutes, and solute is completely dissolved to form uniform solution, so that mixed solution 4 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0220 ÷ 183.48 ≈ 0.1199 × 10-3mol ≈ 0.1199mmol ≈ 0.12mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 174 ℃ for reaction for 24 hours, and after the reaction kettle is naturally cooled to room temperature, carrying out centrifugal separation at the rotating speed of 8500r/min for 4 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with anhydrous ethanol for 4 times until the solution is neutral to obtain washed precipitate; the washing refers to completely dispersing the precipitate in absolute ethyl alcohol by ultrasonic waves, then carrying out centrifugal separation at the rotating speed of 10000r/min for 4 minutes, removing supernatant, and separating to obtain precipitate;
transferring the washed precipitate into a 100ml beaker, drying for 8 hours in an oven at the temperature of 68 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 12%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(5) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0275g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 30 minutes, and the solute is completely dissolved to form a uniform solution, so that a mixed solution 5 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0275 ÷ 183.48 ≈ 0.1498 × 10-3mol ≈ 0.1498mmol ≈ 0.15mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 180 ℃ for reaction for 24 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 10000r/min for 5 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with anhydrous ethanol for 4 times until the solution is neutral to obtain washed precipitate; the washing refers to completely dispersing the precipitate in absolute ethyl alcohol by ultrasonic waves, then carrying out centrifugal separation at the rotating speed of 10000r/min for 4 minutes, removing supernatant, and separating to obtain precipitate;
Transferring the washed precipitate into a 100ml beaker, drying in an oven at 55 ℃ for 11 hours, and fully grinding with an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with 15% of zinc ion doping amount, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(6) preparing a sensor:
a: respectively putting 0.1g of ultrathin molybdenum disulfide nanosheet powder with zinc ion doping amounts of 0%, 4%, 8%, 12% and 15% prepared in the steps (1) - (5) into an agate mortar, respectively adding 3-5 drops of deionized water, and grinding into paste;
b: respectively coating the samples obtained in the step (7) a on electrode sheets of 5 comb-shaped electrodes by using a fine writing brush to form a sensor array consisting of ultrathin molybdenum disulfide nanosheet powder with the zinc ion doping amount of 0%, the zinc ion doping amount of 4%, the zinc ion doping amount of 8%, the zinc ion doping amount of 12% and the zinc ion doping amount of 15%;
(8) And (3) testing the response curve of the sensor array consisting of 5 sensors prepared in the step (6) to ozone, an ozone precursor and volatile organic compounds (formaldehyde and ethanol) by using a Catherine ammeter under the condition of 20 ℃ and 15% of relative humidity, and collecting the response signals of the sensor array to the ozone and the ozone precursor.
The method for detecting the ozone and the ozone precursor has the advantages of low working temperature, good selectivity to the ozone and the ozone precursor and short response time. According to the detection method, the electron depletion layer of the molybdenum disulfide nanosheet is regulated and controlled by controlling the doping amount of zinc ions in the molybdenum disulfide, so that the advantage of large surface area of the molybdenum disulfide nanosheet is combined with the surface state of a zinc ion doping regulation sensing material under the condition that the morphology of the molybdenum disulfide nanosheet is kept unchanged, a gas-sensitive sensor array consisting of 5 sensors is further constructed, and rapid identification and detection of ozone, nitrogen dioxide, ethanol and formaldehyde at a lower working temperature are realized.
example 3.
(1) a: 0.1960g of ammonium molybdate and 2.2836g of thiourea are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 32 minutes, and solutes are completely dissolved to form a uniform solution, so that a mixed solution 1 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, placing the reaction kettle into a forced air drying box with the temperature of 170-190 ℃ for reaction for 22-26 hours, and after the reaction kettle is naturally cooled to room temperature, carrying out centrifugal separation at the rotation speed of 8000-12000r/min for 3-5 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 3 times until the solution is neutral to obtain washed precipitate; the washing is to completely disperse the precipitate in deionized water by ultrasound, then carry out centrifugal separation at the rotating speed of 8000r/min for 5 minutes, remove the supernatant and separate to obtain the precipitate;
transferring the washed precipitate into a 100ml beaker, drying for 9 hours in an oven at the temperature of 60 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 0%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(2) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0037g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 35 minutes, and solute is completely dissolved to form uniform solution, so that mixed solution 2 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0037 ÷ 183.48 ≈ 2.01 × 10-5mol ≈ 2.01 × 10-2mmol ≈ 0.02mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a blowing drying oven with the temperature of 184 ℃ for reaction for 25 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 8000r/min for 5 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 4 times until the solution is neutral to obtain washed precipitate; the washing refers to completely dispersing the precipitate in deionized water by ultrasound, then carrying out centrifugal separation at the rotating speed of 12000r/min for 3 minutes, removing supernatant, and separating to obtain precipitate;
Transferring the washed precipitate into a 100ml beaker, drying for 7 hours in an oven at the temperature of 65 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 1%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(3) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0073g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 33 minutes, and solute is completely dissolved to form uniform solution, so that mixed solution 3 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0073 ÷ 183.48 ≈ 3.978 × 10-6mol ≈ 3.978 × 10-3mmol ≈ 0.04mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 186 ℃ for reaction for 24 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 11000r/min for 4 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 4 times until the solution is neutral to obtain washed precipitate; the washing is to completely disperse the precipitate in deionized water by ultrasound, then carry out centrifugal separation at the rotating speed of 10000r/min for 4 minutes, remove the supernatant and separate to obtain the precipitate;
transferring the washed precipitate into a 100ml beaker, drying in an oven at the temperature of 68 ℃ for 11 hours, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 4%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(4) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0110g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 30 minutes, and solute is completely dissolved to form uniform solution, so that mixed solution 4 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0110 ÷ 183.48 ≈ 5.995 × 10-5mol ≈ 5.998 × 10-2 ≈ 0.06mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 176 ℃ for reaction for 25 hours, and after the reaction kettle is naturally cooled to room temperature, carrying out centrifugal separation at the rotating speed of 9000r/min for 5 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 5 times until the solution is neutral to obtain washed precipitate; the washing refers to completely dispersing the precipitate in deionized water by ultrasound, then carrying out centrifugal separation at a rotating speed of 9000r/min for 4 minutes, removing supernatant, and separating to obtain precipitate;
transferring the washed precipitate into a 100ml beaker, drying for 10 hours in an oven at the temperature of 64 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 6%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(5) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0147g of zinc acetate are added into a beaker containing 35 ml of deionized water, and the mixture is magnetically stirred for 34 minutes, so that solute is completely dissolved to form a uniform solution, and a mixed solution 5 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0147 ÷ 183.48 ≈ 0.8011 × 10-4mol ≈ 0.0801mmol ≈ 0.08mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 188 ℃ for reaction for 23 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 10000r/min for 5 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 5 times until the solution is neutral to obtain washed precipitate; the washing is to completely disperse the precipitate in deionized water by ultrasound, then carry out centrifugal separation at the rotating speed of 8000r/min for 4 minutes, remove the supernatant and separate to obtain the precipitate;
Transferring the washed precipitate into a 100ml beaker, drying for 7 hours in an oven at the temperature of 65 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 8%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(6) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0220g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 31 minutes, and solute is completely dissolved to form uniform solution, so that mixed solution 6 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0220 ÷ 183.48 ≈ 0.1199 × 10-3mol ≈ 0.1199mmol ≈ 0.12mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 176 ℃ for reaction for 25 hours, and after the reaction kettle is naturally cooled to room temperature, carrying out centrifugal separation at the rotating speed of 10000r/min for 4 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 3 times until the solution is neutral to obtain washed precipitate; the washing is to completely disperse the precipitate in deionized water by ultrasound, then carry out centrifugal separation at the rotating speed of 12000r/min for 4 minutes, remove the supernatant and separate to obtain the precipitate;
transferring the washed precipitate into a 100ml beaker, drying for 10 hours in an oven at the temperature of 60 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 12%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(7) a: 0.1960g of ammonium molybdate, 2.2836g of thiourea and 0.0275g of zinc acetate are added into a beaker containing 35 ml of deionized water, the mixture is magnetically stirred for 30 minutes, and the solute is completely dissolved to form a uniform solution, so that a mixed solution 7 is obtained; (amount of ammonium molybdate substance: 0.1960 ÷ 196.0145 ≈ 0.000999mol ≈ 0.001mol ≈ 1 mmol; amount of thiourea substance: 2.2896 ÷ 76.12 ≈ 0.03007mol ≈ 0.0300mol ≈ 30 mmol; amount of zinc acetate substance: 0.0275 ÷ 183.48 ≈ 0.1498 × 10-3mol ≈ 0.1498mmol ≈ 0.15mmol)
b: transferring the mixed solution 1 into a 45 ml sealed polytetrafluoroethylene reaction kettle, putting the reaction kettle into a forced air drying oven with the temperature of 180 ℃ for reaction for 24 hours, and after the reaction kettle is naturally cooled to the room temperature, carrying out centrifugal separation at the rotating speed of 10000r/min for 4 minutes to obtain black molybdenum disulfide precipitate;
washing the precipitate with deionized water for 5 times until the solution is neutral to obtain washed precipitate; the washing is to completely disperse the precipitate in deionized water by ultrasound, then carry out centrifugal separation at the rotating speed of 10000r/min for 4 minutes, remove the supernatant and separate to obtain the precipitate;
Transferring the washed precipitate into a 100ml beaker, drying for 12 hours in an oven at the temperature of 60 ℃, and fully grinding by using an agate mortar to obtain ultrathin p-type molybdenum disulfide nanosheet powder with the zinc ion doping amount of 15%, wherein the thickness of the ultrathin p-type molybdenum disulfide nanosheet powder is 3-20 nm;
(8) Preparing a sensor:
a: respectively putting 0.1g of the ultrathin molybdenum disulfide nanosheet powder with the zinc ion doping amounts of 0%, 2%, 4%, 6%, 8%, 12% and 15% prepared in the steps (1) - (7) into an agate mortar, respectively adding 3-5 drops of deionized water, and grinding into paste;
b: respectively coating the samples obtained in the step (8) a on electrode sheets of 7 comb-shaped electrodes by using a fine writing brush to form a sensor array consisting of ultrathin molybdenum disulfide nanosheet powder with the zinc ion doping amount of 0%, the zinc ion doping amount of 2%, the zinc ion doping amount of 4%, the zinc ion doping amount of 6%, the zinc ion doping amount of 8%, the zinc ion doping amount of 12% and the zinc ion doping amount of 15%;
(8) and (3) testing the response curve of the sensor array consisting of the 7 sensors prepared in the step (7) to ozone, an ozone precursor and volatile organic compounds (formaldehyde and ethanol) by using a Catherine ammeter under the condition of 30 ℃ and the relative humidity of 25%, and collecting the response signals of the sensor array to the ozone and the ozone precursor.
the method for detecting the ozone and the ozone precursor has the advantages of low working temperature, good selectivity to the ozone and the ozone precursor and short response time. According to the detection method, the electron depletion layer of the molybdenum disulfide nanosheet is regulated and controlled by controlling the doping amount of zinc ions in the molybdenum disulfide, so that the advantage of large surface area of the molybdenum disulfide nanosheet is combined with the surface state of a zinc ion doping regulation and control sensing material under the condition that the morphology of the molybdenum disulfide nanosheet is kept unchanged, a gas-sensitive sensor array consisting of 7 sensors is further constructed, and rapid and identification detection of ozone, nitrogen dioxide, ethanol and formaldehyde is realized.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention are within the scope of the technical solution of the present invention.
Claims (7)
1. the method for detecting ozone and an ozone precursor is characterized by comprising the following steps of:
(1) completely dissolving ammonium molybdate, thiourea and zinc acetate in water to obtain a mixed solution; the molar ratio of thiourea to ammonium molybdate to zinc acetate is 3000:100: 0-15;
(2) transferring the mixed solution into a sealed reaction kettle, reacting at the temperature of 170-190 ℃ for 22-26 hours, naturally cooling to room temperature, and performing centrifugal separation to obtain black precipitate;
washing the precipitate with water or anhydrous ethanol until the solution is neutral to obtain washed precipitate; the washing refers to ultrasonically dispersing the precipitate in water or absolute ethyl alcohol, then carrying out centrifugal separation, removing supernatant, and separating to obtain precipitate;
drying the washed precipitate at 50-70 deg.C for 6-12 hr to obtain dried precipitate; fully grinding the dried precipitate to obtain 3-20nm p-type molybdenum disulfide nanosheet powder;
(3) repeating the steps (1) and (2) for not less than 4 times, wherein the molar ratio of ammonium molybdate to zinc acetate is different each time and is different from the molar ratio of ammonium molybdate to zinc acetate in the step (1), so as to obtain not less than 5 types of p-type molybdenum disulfide nanosheet powder with different zinc ion doping amounts;
(4) respectively preparing at least 5 types of p-type molybdenum disulfide nanosheet powder with different zinc ion doping amounts into sensors, and constructing a sensor array consisting of at least 5 sensors;
(5) And respectively detecting the ozone and the ozone precursor by using a sensor array, and collecting response signals of the sensor array to the ozone and the ozone precursor.
2. The detection method according to claim 1, wherein,
In the step (1), ammonium molybdate, thiourea and zinc acetate are added into water and dissolved by means of magnetic stirring.
3. The detection method according to claim 1, wherein,
in the step (2), after cooling to room temperature, the rotation speed of centrifugal separation is 8000- & ltSUB & gt 12000r/min, and the time is 3-5 minutes;
The number of washing times is 3-5.
4. the detection method according to claim 3, wherein,
Washing in the step (2): the rotation speed of the centrifugal separation is 8000-12000r/min, and the time is 3-5 minutes.
5. the detection method according to claim 4, wherein,
in the step (2), the reaction temperature is 180 ℃, and the reaction time is 24 hours;
the drying temperature was 60 ℃.
6. the detection method according to claim 1, wherein,
In the step (5), the detection temperature is 20-30 ℃ and the relative humidity is 15-25%.
7. The detection method according to any one of claims 1 to 6, wherein,
The water is deionized water.
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