CN102133524A

CN102133524A - Load type Pt/TiO2/Al2O3 fiber composite photocatalyst and preparation method thereof

Info

Publication number: CN102133524A
Application number: CN2011100429850A
Authority: CN
Inventors: 安保礼; 戴樊增; 黄小迪
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2011-02-23
Filing date: 2011-02-23
Publication date: 2011-07-27
Anticipated expiration: 2031-02-23
Also published as: CN102133524B

Abstract

The invention relates to a load type Pt/TiO2/Al2O3 fiber composite photocatalyst and a preparation method thereof. The catalyst is the composite photocatalyst which takes Al2O3 fiber as a carrier and is formed by loading Pt/TiO2 on the carrier, wherein the mass of the Pt/TiO2 is 10% of that of the Al2O3 fiber; and the mass ratio of the Pt to TiO2 in the Pt/TiO2 is 5:1000. The catalytic activity of the load type photocatalyst is close to that of a photocatalyst dispersed in a solution, and the load type photocatalyst has high catalytic activity and good stability and is reusable. The Al2O3 fiber is light per se, easy to suspend in water and convenient for recycling. The preparation method is simple and highly effective, can be used for large-scale preparation, and has lower cost and practical significance in the application field of treating pollutants with water.

Description

Support type Pt/TiO＜sub〉2＜/sub 〉/Al＜sub〉2＜/sub〉O＜sub〉3＜/sub〉the fiber composite photochemical catalyst and preparation method thereof

Technical field

The present invention relates to a kind of nano-photocatalyst functional material and preparation method thereof, particularly a kind of support type Pt/TiO ₂/ Al ₂O ₃Fiber composite photochemical catalyst and preparation method thereof.

Technical background

China is in industrialization high-speed development period in the last thirty years, and the overall national strength of country and the people's living standard constantly promote, but ecological environment is subjected to serious destruction.Wherein water pollution problems is particularly serious, contains in the waste water and is difficult to biodegradable organic pollution in a large number, as chlorobenzene organic matter, chlorophenol compound etc.Therefore these material serious harm human healths, using low-cost technologies to handle organic pollution in the water is to be badly in need of the significant problem that solves.

Photocatalysis degradation organic contaminant has the reaction condition gentleness, non-secondary pollution, advantage such as processing cost is lower.Owing to itself can not consume in the light-catalyzed reaction, there is not adverse side effect again, therefore become one of important method of administering the water pollution.

Nano titanium oxide is as photochemical catalyst, because of it has the favor that advantages such as photostability, high efficiency, nontoxic, cheapness enjoy people.Yet the main extensive use that exists two problems restricting titanium dioxide optical catalyst in practice: the energy gap of (1) anatase titanium dioxide is 3.2eV, can only absorb the higher ultraviolet ray of energy, and the utilization rate of sunshine is low; (2) nano-titanium dioxide powder easily reunion inactivation, particle itself sedimentation and catalytic effect is descended easily in sewage disposal process, and also suitable difficulty of catalyst recovery, use cost is higher and so cause the secondary pollution problems of water.Therefore, titanium dioxide is carried out modification and load to improve the photocatalysis effect of titanium dioxide.

With the nanometer Pt particle load of trace on the titanium dioxide semiconductor surface, make the electronics and the hole that generate after the illumination distinguish localization on Pt particle and semiconductor TiO 2 particles, separate, oxidation-reduction reaction takes place in each comfortable different position of electronics and hole then.Owing to suppressed the compound of electronics and hole behind the nanometer Pt particle load, thereby improved the photocatalytic activity and the selectivity of nano titanium dioxide photocatalyst greatly.

In the technology of carried titanium dioxide, reported that the carrier of employing has bead, glass plate, porous alumina ceramic film, NACF etc.Usually activity of such catalysts reduces because of the change of specific surface in loading process, and catalyst and carrier-bound poor stability come off easily, and some preparation technology is very complicated, costs an arm and a leg.

Summary of the invention

The object of the present invention is to provide a kind of support type Pt/TiO ₂/ Al ₂O ₃The fiber composite photochemical catalyst.

Two of purpose of the present invention is to provide this Preparation of catalysts method.

For achieving the above object, the present invention adopts following technical scheme:

A kind of support type Pt/TiO ₂/ Al ₂O ₃The fiber composite photochemical catalyst is characterized in that this catalyst is with/Al ₂O ₃Fiber is a carrier, and load has Pt/TiO ₂And the composite photo-catalyst that forms, wherein Pt/TiO ₂Quality be Al ₂O ₃10% of quality of fiber; And Pt/TiO ₂Middle Pt and TiO ₂Mass ratio be 5:1000.

Above-mentioned TiO ₂Be anatase-type nanometer titanium dioxide.

A kind ofly prepare above-mentioned support type Pt/TiO ₂/ Al ₂O ₃The fiber composite photochemical catalyst is characterized in that the concrete steps of this method are:

A. titanic oxide nano powder is joined the H that concentration is 0.01mol/L ₂PtCl ₆In the aqueous solution, and the mol ratio of control Pt and titanium dioxide is 1:480; Add volume ratio V then _{Methyl alcohol}/ V _WaterThe methanol aqueous solution of=1:10; Regulator solution pH value to 6.8 ~ 7.0; Shone 3 ~ 5 hours with the 300W xenon lamp after stirring; Obtain compound by centrifugation, washing; This compound drying, cooling back are ground and are obtained dark gray powder; With this dark gray powder 400 ~ 500 ⁰C calcining 2 ~ 4 hours; Obtain the Pt/TiO of grey black ₂Powder;

B. with Al ₂O ₃Fiber is dried 200 ~ 300 with ethanol supersound washing 3 ~ 5 times ⁰C heat treatment 3 ~ 5 hours; With steps A gained Pt/TiO ₂Powder is scattered in the aqueous solution, ultrasonic 5 ~ 15 minutes; With Al ₂O ₃Fiber impregnation makes Pt/TiO in this solution ₂Powder evenly is adsorbed in Al ₂O ₃Fiber surface; After the drying, 200 ~ 300 ⁰C heat treatment 2 ~ 3 hours obtains support type Pt/TiO ₂/ Al ₂O ₃Fiber catalyst C; Pt/TiO wherein ₂Powder and Al ₂O ₃The quality of fiber ratio is.

The support type Pt/TiO that the present invention is prepared ₂/ Al ₂O ₃The advantage of fiber photocatalyst is: the catalytic activity of gained loaded catalyst of the present invention approaches to be scattered in the photochemical catalyst in the solution, has high catalytic activity, and has good stability, and is reusable.Al ₂O ₃Fiber itself is very light, suspends in water easily, very is convenient to reclaim.The preparation method is simply efficient, can prepare in a large number, and cost is lower, has practical significance in water treatment contaminant applications field.

Description of drawings

Fig. 1 is the XRD figure of anatase-type nanometer titanium dioxide;

Fig. 2 is Pt/TiO ₂The XRD figure of composite catalyst;

Fig. 3 is support type Pt/TiO ₂/ Al ₂O ₃The SEM figure of fiber catalyst;

Fig. 4 is anatase-type nanometer titanium dioxide catalyst and Pt/TiO ₂Composite catalyst is to methyl orange the disposal efficiency comparison diagram;

Fig. 5 is Pt/TiO under the different condition ₂Composite catalyst and support type Pt/TiO of the present invention ₂/ Al ₂O ₃Fiber catalyst is to methyl orange the disposal efficiency test comparison diagram;

Fig. 6 is Pt/TiO of the present invention ₂/ Al ₂O ₃Fibre composite catalyst light degradation methyl orange replica test.

The specific embodiment

Embodiment one: the cryosol gel process for preparing of anatase-type nanometer titanium dioxide sees also document Sifang Li, * Guoliang Ye, and Guoqin Chen. J. Phys. Chem. C 2009,113,4031, be specially: the 10g butyl titanate is dissolved in the 40ml absolute ether, adds the 12ml glacial acetic acid more inward, fully stirred 1 hour.Dropwise add the mixed solution (10ml water, 5ml glacial acetic acid) of glacial acetic acid and water, fully stirred 1 ~ 3 hour.With the white gels sealing and standing that generates 1 ~ 3 day, remove supernatant liquor, with lower floor's gel 120 ⁰The C oven dry, cooling back grind into powder.Use the deionized water cyclic washing, centrifugal, become neutral until product.With product 100 ~ 120 ⁰The C oven dry, grind into powder is put into crucible with powder then, under air atmosphere, 400 ~ 500 ⁰C calcining 1 ~ 3 hour.Obtain white powder anatase-type nanometer titanium dioxide catalyst A at last, its XRD figure is referring to Fig. 1.

Embodiment two: the H that adds 1.30ml 0.01mol/L in 0.5g embodiment one gained anatase-type nanometer titanium dioxide powders A ₂PtCl ₆The aqueous solution adds 250ml(V then _{Methyl alcohol}/ V _Water=1:10) methanol aqueous solution is with NaOH aqueous solution regulator solution pH value to 6.8 ~ about 7.0.Shone 3 ~ 5 hours with the 300W xenon lamp after stirring.After the illumination, obtain compound by centrifugal, washing.Centrifugal afterproduct is 100 ~ 120 ⁰The C oven dry, the cooling back is ground and is obtained dark gray powder.Under air atmosphere, 400 ~ 500 ⁰C calcining 2 ~ 4 hours.Obtain the 0.5wt% Pt/TiO of grey black ₂Fine catalyst B.Referring to accompanying drawing 2.

Embodiment three: with commercial Al ₂O ₃Fiber is dried with ethanol supersound washing 3 ~ 5 times.Under air atmosphere, 200 ~ 300 ⁰C heat treatment 3 ~ 5 hours.Get the embodiment two gained 0.5wt% Pt/TiO of 20mg ₂Powder B is scattered in the aqueous solution, ultrasonic 5 ~ 15 minutes.With Al ₂O ₃Fiber 200mg is immersed in the solution, makes powder B evenly be adsorbed in Al ₂O ₃Fiber surface.After the oven dry, under air atmosphere, 200 ~ 300 ⁰C heat treatment 2 ~ 3 hours obtains support type Pt/TiO ₂/ Al ₂O ₃Fiber optic composite catalyst C.Referring to accompanying drawing 3.

The catalytic activity of loaded photocatalyst and stability test

Document Sifang Li, * Guoliang Ye, and Guoqin Chen. J. Phys. Chem. C 2009,113,4031 shows the titanium dioxide optical catalyst Degussa P-25 of catalyst A compared with commerce usefulness, demonstrates higher photocatalytic activity.We measure the photocatalytic activity of catalyst A and catalyst B with the degradation rate size of methyl orange solution.Experiment condition is: it is the methyl orange solution of 5mg/L 100ml that initial concentration is selected in experiment for use.The quality of catalyst A and catalyst B all is 20mg.With 18W ultra violet lamp 2 hours,, detect residue methyl orange concentration with ultraviolet-uisible spectrophotometer, and calculate degradation rate every 15 minutes sample analysis.Experimental result shows that the photocatalytic activity of catalyst B is higher than catalyst A.The methyl orange degradation rate of illumination rear catalyst half an hour A and catalyst B is respectively 44.5% and 74.5%.So Pt/TiO ₂Catalyst B demonstrates high photocatalytic activity.(accompanying drawing 4)

The catalytic activity that our continuation comes evaluate catalysts C with the degradation rate size of methyl orange solution.Experiment condition is: it is the methyl orange solution of 5mg/L 100ml that initial concentration is selected in experiment for use.Catalyst 0.5wt% Pt/TiO in the experiment ₂The contained quality of powder B all is 20mg.18W ultra violet lamp 2 hours every 15 minutes sample analysis, detects the concentration of residue methyl orange with ultraviolet-uisible spectrophotometer, and calculates degradation rate.Do 3 groups of parallel laboratory tests respectively.

First group of experiment, catalyst B is scattered in the methyl orange solution.The overall optical chemical reaction process is in stirring all the time.Second group of experiment, catalyst B is scattered in the methyl orange solution.The overall optical chemical reaction process is in static condition.The 3rd group of experiment, Pt/TiO ₂/ Al ₂O ₃Fiber catalyst C.Catalyst C is immersed in the methyl orange solution.The overall optical chemical reaction process is in static condition.

Experimental result shows that the degradation rate of illumination three groups of experiment methyl orange solutions after 1 hour all surpasses 90%.Because the water treatment organic pollution is in static environment mostly in actual applications, so support type Pt/TiO ₂/ Al ₂O ₃Fiber catalyst demonstrates high catalytic activity, and catalyst C suspends in water easily simultaneously, easily reclaims, and is reusable, can be used for actual sewage disposal.(accompanying drawing 5)

Pt/TiO ₂/ Al ₂O ₃Behind the fiber catalyst C degraded methyl orange solution, use distilled water immersion 2 hours.After the oven dry, continue to carry out the light degradation test as catalyst, experiment condition is identical, repeats altogether 2 times.Experimental result shows that the degradation rate of illumination 3 test methyl oranges after 1 hour reaches 94.0%, 92.6% and 87.7% respectively, considers factors such as experimental error, experimental result explanation support type Pt/TiO ₂/ Al ₂O ₃Fiber catalyst has stability preferably.(accompanying drawing 6).

Claims

1. support type Pt/TiO ₂/ Al ₂O ₃The fiber composite photochemical catalyst is characterized in that this catalyst is with/Al ₂O ₃Fiber is a carrier, and load has Pt/TiO ₂And the composite photo-catalyst that forms, wherein Pt/TiO ₂Quality be Al ₂O ₃10% of quality of fiber; And Pt/TiO ₂Middle Pt and TiO ₂Mass ratio be 5:1000.

2. one kind prepares support type Pt/TiO according to claim 1 ₂/ Al ₂O ₃The fiber composite photochemical catalyst is characterized in that the concrete steps of this method are:

B. with Al ₂O ₃Fiber is dried 200 ~ 300 with ethanol supersound washing 3 ~ 5 times ⁰C heat treatment 3 ~ 5 hours; With steps A gained Pt/TiO ₂Powder is scattered in the aqueous solution, ultrasonic 5 ~ 15 minutes; With Al ₂O ₃Fiber impregnation makes Pt/TiO in this solution ₂Powder evenly is adsorbed in Al ₂O ₃Fiber surface; After the drying, 200 ~ 300 ⁰C heat treatment 2 ~ 3 hours obtains support type Pt/TiO ₂/ Al ₂O ₃Fiber catalyst C; Pt/TiO wherein ₂Powder and Al ₂O ₃Quality of fiber is than being 1:10.