CN117797830A - Low-load Pt-based catalyst and preparation method and application thereof - Google Patents
Low-load Pt-based catalyst and preparation method and application thereof Download PDFInfo
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Abstract
The invention discloses a low-load Pt-based catalyst, which comprises a carrier, transition metal oxide and Pt; the transition metal oxide is dispersed on the carrier in the form of nanometer islands; pt is selectively deposited and dispersed on the transition metal oxide nano islands under the action of a coupling agent; based on the mass of the low-loading Pt-based catalyst, the contents of Pt and transition metal are respectively 0.05-0.5 wt% and 0.5-5 wt% based on the atomic mass. The invention also discloses a preparation method of the low-load Pt-based catalyst and application of the low-load Pt-based catalyst in CO preferential oxidation reaction and formaldehyde elimination reaction in hydrogen-rich atmosphere. The preparation method has the advantages of mild conditions, simple operation, environmental protection and the like, the low-load Pt-based catalyst has a wider CO conversion temperature window in CO preferential oxidation reaction in a hydrogen-rich atmosphere, and formaldehyde can be completely eliminated at room temperature.
Description
Technical Field
The invention relates to the technical field of solid catalysts, in particular to a low-load Pt-based catalyst and a preparation method and application thereof.
Background
Proton Exchange Membrane Fuel Cells (PEMFCs) using high purity hydrogen as fuel have wide application prospects due to the advantages of small volume, low operating temperature, high energy density, fast start-up rate and the like, while trace CO in hydrogen-rich gas streams can poison electrodes. The preferential oxidation of CO in hydrogen-rich gas (CO-PROX) is the most direct and effective method for removing CO from practical and economical point of view, but often requires a high temperature of 100 ℃ or higher to reduce CO to ppm level or below due to insufficient activity (chinese patent publication No. CN114515580 a). Therefore, it is imperative to develop a high performance CO-PROX catalyst that can meet the PEMFC operating temperature (less than or equal to 80 ℃).
Formaldehyde is one of the main pollutants in closed spaces, especially in just decorated family rooms, and long-term contact of trace formaldehyde can cause diseases such as sphagitis, bronchitis, pneumonia, lung cancer and the like, so that the elimination of formaldehyde at room temperature has very important significance for human health and social development.
Pt-based catalysts are used in oxidation reactions (including CO-PROX and formaldehyde oxidation reactions)Has wide application. In the CO preferential oxidation reaction, the choice of carrier is largely divided into two types, one being a reducible metal oxide such as iron oxide or the like, and the other being an inert carrier such as silica, activated carbon or the like. When the metal oxide is used as a carrier, the valence of the reducible metal oxide is modulated by heat treatment of the catalyst to increase O 2 To obtain high activity, but too much activated oxygen causes H when the temperature reaches above 100 DEG C 2 Leading to a significant reduction in CO conversion. Zhang et al in CeO 2 Preparation of Pt/CeO for support 2 The catalyst being used for preferential oxidation, but when the temperature reaches above 120 ℃, H 2 The oxidation aggravation results in a rapid decrease in the conversion of CO, which is far below the CO conversion temperature window [ appl. Catalyst. B-environ.2013,615-625 ]]. When inert materials are used as carriers, due to the poisoning effect of CO on Pt, the catalyst has insufficient oxygen activating capability, so that high-activity is often realized at a higher temperature or with high Pt loading capacity, and the Pt/Al is modified by A auxiliary agents such as Ag, fe and the like and B auxiliary agents such as K, na and the like 2 O 3 The catalyst is used for removing CO in reformed gas, and the reduction of CO below ppm level can be realized only by high temperature of above 100 ℃ (Chinese patent document with publication number of CN 101879453A).
The inert high specific surface area material is taken as a substrate, so that the dispersion of metal can be promoted, the strong interaction between Pt and metal oxide can be enhanced, and the oxygen activating capacity can be regulated. In order to effectively construct the interface effect between Pt and metal oxide, a one-pot method is generally adopted to prepare the catalyst, but the catalyst is often subjected to high-temperature treatment in the process of exciting the performance of the metal oxide, and sintering of Pt is initiated in the process. The Pt-Fe/CNTs catalyst prepared by Chen et al one-pot method can completely eliminate CO at 40 ℃ [ int.J.Hydrogen Energy,2016,14079-14087 ]]However, the Pt-Fe component is treated at high temperature in the preparation process to trigger the Pt agglomeration particle size to be more than 7nm, so that the utilization rate of Pt atoms is low, high Pt loading is required, and the preparation cost is high. Therefore, how to avoid sintering of Pt is a difficult problem. Wang Gongjuan preparation of Cu/PtM/CNTs (wherein M is Fe, co or Ni) for methanol fuel cell cathode catalysts by Cu coating in a metal coated manner to prevent Pt particles from sinteringHowever, the preparation process is complicated, and most of the active sites are covered due to the coating of Cu on Pt, so that the Pt load amount is as high as 10wt.%, and the actual application requirement (Chinese patent document with publication number of CN 101380584A) can not be met. Lu et al obtain Fe-Pt/SiO by atomic layer deposition 2 The catalyst avoids the high-temperature agglomeration of Pt, and CO can be completely eliminated at room temperature, however, the high requirement of the preparation method on equipment is difficult to realize industrial application [ Nature,2019,565:631-635 ]]。
In catalytic reactions, since chloride ions poison the catalytically active sites and destroy the catalyst structure, which results in catalyst deactivation, it is generally necessary to use more expensive chlorine-free platinum-containing reagents in the preparation of Pt-based catalysts, or to remove chloride ions by extensive washing, thereby generating a large amount of chlorine-containing wastewater, which limits the preparation of catalysts to some extent [ appl.
The reported Pt-based catalyst still has the problems of low activity, complicated preparation steps, easy sintering of Pt caused by weak acting force between metals, chloride ion poisoning and the like, and prevents industrial practical application.
Disclosure of Invention
In view of the problems existing in the prior art, the invention provides a low-load Pt-based catalyst and a preparation method and application thereof.
The technical scheme of the invention is as follows:
a low-load Pt-based catalyst, which comprises a carrier, a transition metal oxide and Pt;
the transition metal oxide is dispersed on the carrier in the form of nanometer islands; pt is selectively deposited and dispersed on the transition metal oxide nano islands under the action of a coupling agent;
based on the mass of the low-loading Pt-based catalyst, the contents of Pt and transition metal are respectively 0.05-0.5 wt% and 0.5-5 wt% based on the atomic mass.
Preferably, the carrier is a carbon nanotube; the transition metal oxide is at least one of Fe, ce, co, mn oxide.
Further preferably, the carbon nanotubes are multiwall carbon nanotubes.
Preferably, pt is dispersed on the transition metal oxide nanoislands as clusters of 1-2 nm size.
Transition metal oxide MO supported by carbon nano tube as carrier x And Pt is selectively deposited on the transition metal oxide nano island through a coupling agent, so that strong interaction between Pt and the transition metal oxide is promoted, oxygen vacancies are promoted to be generated, and the catalyst is beneficial to O 2 The adsorption and activation of the catalyst effectively improve the catalytic performance of oxidation reaction. Compared with the prior art, the low-load Pt-based catalyst Pt-MO of the invention x The preparation condition of the CNTs is mild, the high-temperature sintering of noble metal Pt is avoided, and the CNTs have the advantages of low loading and high activity.
The low-load Pt-based catalyst is applicable to, but not limited to, CO preferential oxidation reaction in hydrogen-rich atmosphere, CO can be completely eliminated in a wider CO conversion temperature window (20-200 ℃), and the purification of a hydrogen source in a proton exchange membrane fuel cell is realized; the method can also be used for completely eliminating formaldehyde at room temperature, converting the formaldehyde into carbon dioxide and water, and realizing air purification.
The invention also provides application of the low-load Pt-based catalyst in CO preferential oxidation reaction in a hydrogen-rich atmosphere, wherein the reaction temperature is 20-200 ℃.
Preferably, the application comprises: passing the CO-rich gas to be treated through a fixed bed reactor containing the low-loading Pt-based catalyst, wherein the mass space velocity is 1.8X10 3 ～3.6×10 5 mL g cat -1 h -1 The reaction temperature is 20-200 ℃.
The invention also provides application of the low-load Pt-based catalyst in formaldehyde elimination, and the reaction temperature is 20-80 ℃.
Preferably, the application comprises: the formaldehyde-containing gas to be treated is passed through a fixed bed reactor equipped with a Pt-based catalyst of low loading, with a mass space velocity of 6 x 10 3 ～6×10 5 mL g cat -1 h -1 The reaction temperature is 20-80 ℃.
Further preferably, the formaldehyde-containing gas has a formaldehyde concentration of 100 to 500ppm and further contains 5 to 20vol.% O 2 。
The invention also provides a preparation method of the low-load Pt-based catalyst, which comprises the following steps:
step 1: soaking carrier in transition metal M source solution, regulating pH value, stirring, aging, filtering, washing, drying, and roasting under inert atmosphere to obtain MO x A carrier;
step 2: dissolving a Pt source in low-carbon alcohol, mixing the Pt source with a strong alkali low-carbon alcohol solution, and reducing the mixture in an inert atmosphere to obtain Pt sol;
step 3: dispersing Pt sol in coupling agent and MO x Mixing the carriers, stirring, dipping, drying and reducing to obtain a low-load Pt-based catalyst;
the transition metal M includes at least one of Fe, ce, co, mn.
The source of transition metal M is a water-soluble compound of transition metal M.
Preferably, in step 1, the concentration of the transition metal M source solution is 0.5 to 10X 10 -3 mol L -1 。
When the concentration of the transition metal M source solution is too low, MO is obtained x Less transition metal oxide nano islands in the support, resulting in Pt-MO in the final catalyst x Too few structure and insufficient catalytic activity; when the concentration of the transition metal M source solution is too high, the catalytic activity of the final catalyst is also poor.
Further preferably, in step 1, the concentration of the transition metal M source solution is 1 to 2X 10 -3 mol L -1 。
In the step 1, the pH value is regulated to 8-10. The pH value can be regulated by using alkali, wherein the alkali is NaOH or Na 2 CO 3 、NH 3 ·H 2 At least one of O.
In the step 1, the stirring time is 1-3 h; aging time is 1-3 h; the drying temperature is 80-120 ℃; the roasting temperature is 300-500 ℃ and the roasting time is 3-5 h.
In the step 2, the lower alcohol is at least one of ethylene glycol, glycerol and 1, 4-butanediol; the strong base is NaOH and/or KOH; inert atmosphere of N 2 At least one of He and Ar.
In the step 3, the coupling agent is at least one of aminosilane, carboxyl silane and triethanolamine. The coupling agent molecules such as triethanolamine, aminosilane, carboxyl silane and the like contain two chemical groups with different properties, and can form a chemical combination or complexing structure with target metals through ionic bonds or coordination bonds, so that the same kind of coupling agent has the same effect.
Coupling agents promote Pt at transition metal oxide MO via metal-ligand bonds x And (3) performing selective deposition and dispersion.
In the step 3, the volume fraction of the Pt sol and the coupling agent is 1-15%.
In the step 3, the stirring time is 0.5-3 h; the dipping time is 12-24 hours; the drying is vacuum drying, the drying time is 12-24 h, and the drying temperature is 80-120 ℃; reducing atmosphere of 10-100 vol% H 2 Ar is an equilibrium atmosphere; the reduction time is 0.5 to 2 hours, the flow rate of the reducing atmosphere is 20 to 50mL min -1 。
Compared with the prior art, the invention has the beneficial effects that:
1. the preparation method of the invention selectively deposits Pt on the metal oxide MO by a coupling agent x On the nanometer island, pt-MO is avoided x Agglomeration of Pt during calcination, and enhancement of Pt and metal oxide MO x The interaction is strong, and the preparation method is simple and easy to operate.
2. The preparation method is simple, the requirement on synthesis equipment is low, the most economical chloroplatinic acid is used as a platinum source, the preparation cost is reduced, chloride ions are stripped from a Pt coordination structure in the sol preparation process, the poisoning of the chloride ions in the catalytic reaction of the Pt active center is eliminated, the elution of the chloride ions is not needed, and the wastewater is reduced.
3. The catalyst prepared by the preparation method has better catalytic performance and Pt load capacity in the oxidation reaction (comprising CO oxidation reaction and room-temperature formaldehyde elimination reaction under hydrogen-rich atmosphere) taking oxygen as a reaction atmosphere, which is far lower than that of the noble metal-based catalyst reported at present.
Drawings
FIG. 1 is a schematic diagram of a catalyst structure, wherein (a) is a catalyst prepared in comparative example 3 and (b) is a low-loading Pt-based catalyst of the present invention.
FIG. 2 shows (a) HAADF-STEM and particle size statistics of the catalyst prepared in example 1 of the present invention, (b) Pt-FeO x Position distribution (circle).
FIG. 3 is a schematic diagram of H of the catalyst prepared in example 1 and comparative examples 1 and 2 of the present invention 2 -a TPR map.
FIG. 4 is a graph showing the performance test of the preferential oxidation reaction of CO with the catalysts prepared in examples 1, 2 and 3 of the present invention.
FIG. 5 is a graph showing the performance test of the preferential oxidation reaction of CO with the catalysts prepared in examples 1,4 and 5 of the present invention.
FIG. 6 is a graph showing the performance test of preferential oxidation reaction of CO with the catalysts prepared in example 1 and comparative examples 1 and 2.
FIG. 7 is a graph showing the performance test of the preferential oxidation reaction of CO with respect to the catalysts prepared in examples 1, 6, 7, 8 and comparative example 3 of the present invention.
FIG. 8 is a graph showing formaldehyde elimination performance test of the catalysts prepared in example 1 and comparative examples 1 and 2 of the present invention.
Detailed Description
Example 1:
dispersing 1.0g CNTs in 100mL concentration of 1.8X10 -3 mol L -1 Stirring in water bath at 80deg.C and pH of 9 for 3 hr, standing for 1 hr, filtering while hot, and washing. Drying the filter cake in a 110 ℃ oven for 12 hours, and roasting in a tubular furnace at 350 ℃ for 4 hours under Ar atmosphere to obtain 1FeO x /CNTs。
50mL of the mixture was concentrated to 0.04mol L -1 H of (2) 2 PtCl 6 ·6H 2 The O ethylene glycol solution is placed in a 250mL three-necked flask, and 50mL of 0.25mol L concentration is added together -1 Stirring and mixing for 1h at room temperature, and then transferring into an oil bath pot at 160 ℃ for reduction for 3h to obtain the Pt colloid solution.
0.54mL of Pt colloid solution is added with triethanolamine to be diluted to 10mL, and 1.0g of Pt colloid solution is added1FeO x The CNTs were impregnated, dried at room temperature for 12H, then dried in a vacuum oven at 120deg.C for 12H at 20vol.% H 2 Reducing for 0.5h under Ar atmosphere to obtain 0.2wt% Pt-1wt% Fe/CNTs catalyst, which is named as 0.2Pt-1FeO x /CNTs。
Example 2:
the procedure was as in example 1, except that the volume of the Pt colloid solution was 0.14mL, and triethanolamine was added to dilute to 10mL, and the remaining steps were identical, to give a 0.05wt% Pt-1wt% Fe/CNTs catalyst, designated 0.05Pt-1FeO x /CNTs。
Example 3:
the procedure was as in example 1, except that the volume of the Pt colloid solution was 1.35mL, and triethanolamine was added to dilute to 10mL, and the remaining steps were identical, to give a 0.5wt% Pt-1wt% Fe/CNTs catalyst, designated 0.5Pt-1FeO x /CNTs。
Example 4:
the procedure is as in example 1, except that the ferric nitrate solution is used at a concentration of 9X 10, as compared to example 1 -4 mol L -1 The rest steps are consistent, and 0.2wt percent Pt-0.5wt percent Fe/CNTs catalyst is obtained and is marked as 0.2Pt-0.5FeO x /CNTs。
Example 5:
the procedure is as in example 1, except that the ferric nitrate solution is used at a concentration of 9X 10, as compared to example 1 -3 mol L -1 The rest steps are consistent, and 0.2wt percent Pt-5wt percent Fe/CNTs catalyst is obtained and is recorded as 0.2Pt-5FeO x /CNTs。
Example 6:
the procedure is as in example 1, except that a salt solution of 7.2X10 is used as compared with example 1 -4 mol L -1 Cerium nitrate solution, and the rest steps are consistent, and 0.2wt percent Pt-1wt percent Ce/CNTs catalyst is obtained and is recorded as 0.2Pt-1CeO x /CNTs。
Example 7:
the procedure is as in example 1, except that the salt solution used is a manganese nitrate solution and the remaining steps are identical to those of example 1, yielding 0.2wt% Pt-1wT% Mn/CNTs catalyst, designated 0.2Pt-1MnO x /CNTs。
Example 8:
the procedure is as in example 1, except that a salt solution of 1.7X10 is used as compared with example 1 -3 mol L -1 Cobalt nitrate solution, the rest steps are consistent, and 0.2wt percent Pt-1wt percent Co/CNTs catalyst is obtained and is marked as 0.2Pt-1CoO x /CNTs。
Comparative example 1:
0.54mL of the Pt sol of example 1 was diluted to 10mL with ethylene glycol, 1.0g of CNTs was impregnated therein, dried at room temperature for 12h, then dried in a vacuum oven at 120deg.C for 12h at 20vol% H 2 Reduction was carried out under an Ar atmosphere for 0.5h to give 0.2wt% Pt/CNTs catalyst, designated 0.2Pt/CNTs.
Comparative example 2:
the procedure was as in example 1, except that no Pt sol was added and the remaining steps were identical to those described in example 1, giving a 1wt% Fe/CNTs catalyst, designated 1FeO x CNTs. Comparative example 3:
the procedure was as in example 1, except that the Pt sol was not diluted with triethanolamine and the remaining steps were identical to those described in example 1, giving a 0.2wt% Pt-1wt% Fe/CNTs-N catalyst, designated 0.2Pt-1FeO x /CNTs-N。
To evaluate the catalytic performance of the prepared catalyst, the catalyst was subjected to a CO preferential oxidation reaction performance test by a micro-reverse evaluation device. 100mg of catalyst is weighed by adopting a fixed bed reactor and is filled in a U-shaped reaction tube, and the inlet flow is 30mL min -1 Is 1vol.% CO,1vol.% O 2 ，40vol.％H 2 Ar is balance gas, and the mass airspeed is 1.8X10 4 mL·g cat -1 h -1 The catalysts were tested for temperature programmed activity. The test temperature interval is 20-200 ℃, and each temperature is kept for 20min, and the concentration of CO in the outlet of the reactor is detected by adopting a sample-collecting record chromatograph.
The method for calculating the CO conversion rate is as follows:
CO Conversion(％)＝([CO] in -[CO] out )/[CO] in ×100％；
wherein: [ CO ]] in The chromatographic peak area corresponding to the CO at the inlet of the reactor;
[CO] out the chromatographic peak areas corresponding to the CO at the outlet of the reactor at different reaction temperatures.
To evaluate the catalytic performance of the prepared catalyst, the catalyst was subjected to formaldehyde elimination performance test by a micro-reverse evaluation device. Adopting a fixed bed reactor, loading 50mg of catalyst into a U-shaped reaction tube, and introducing the catalyst into the U-shaped reaction tube at a flow rate of 100mL min -1 Is 400ppm HCHO,20vol% O 2 Ar is balance gas, and the mass airspeed is 6×10 4 mLg cat -1 h -1 The catalysts were tested for temperature programmed activity. The test temperature interval is 20-80 ℃, samples are sampled every 20min, three samples are sampled at each temperature point, and CO in the outlet of the chromatographic detection reactor is recorded 2 Is a concentration of (3). Due to CO during the experiment 2 In ppm order, a nickel reformer is installed in the FID detector of the chromatograph to capture CO 2 Concentration of CO produced 2 At H 2 Hydrogenation in atmosphere to complete conversion to CH 4 From CH 4 Is used for quantifying the concentration of the product CO 2 Is a concentration of (3).
The HCHO conversion was calculated as follows:
HCHO Conversion(％)＝[CO 2 ]/[CO 2 ] A ×100％；
wherein: [ CO ] 2 ] A For complete conversion of formaldehyde to CO 2 Time-corresponding CH 4 Chromatographic peak area;
[CO 2 ]for CO generated under different reaction temperature conditions 2 Corresponding CH 4 Chromatographic peak area.
Results
As can be seen from FIG. 1, in the low-loading Pt-based catalyst prepared by the present invention, the Pt nanoclusters are more uniform in size and are selectively deposited and highly dispersed in the metal oxide MO under the action of the coupling agent, as compared with the catalyst prepared by the conventional preparation method (FIG. 1 (a)) x On the nano-islands (fig. 1 (b)).
From HAADF of the catalyst of FIG. 2STEM Picture shows that Pt is homogeneously and highly dispersed in FeO as nanoparticles with an average particle diameter of 1.8nm in the catalyst prepared in example 1 x On the nano islands.
FIG. 3 shows Pt-FeO loading on CNTs x There is a strong interaction between them, promoting FeO x To generate more oxygen vacancies and further increase the O of the catalyst 2 Is used for the adsorption activation of the catalyst.
FIG. 4 shows that 0.05Pt-1FeO x The CO conversion rate of the CNTs catalyst is gradually improved along with the temperature rise, and the CO is completely converted at 120 ℃;0.2Pt-1FeO x CNTs and 0.5Pt-1FeO x The CNTs catalyst has excellent catalytic performance in CO preferential oxidation reaction, and CO is completely eliminated within the temperature range of 20-200 ℃.
FIG. 5 shows that different FeOs x The content has different effects on the catalyst performance. The results showed 0.2Pt-1FeO x The activity of the CNTs catalyst is optimal, and CO can be completely eliminated within the temperature range of 20-200 ℃.
FIG. 6 shows that 1FeO x The CNTs are almost inactive in CO preferential oxidation reaction, 0.2Pt/CNTs reach complete CO conversion at 140-160 ℃,0.2Pt-1FeO x The activity of the CNTs is optimal, and CO can be completely eliminated within the temperature range of 20-200 ℃.
FIG. 7 shows that 0.2Pt-1FeO with coupling agent added x Compared with the CO preferential oxidation performance of the CNTs catalyst, the CO preferential oxidation performance of the CNTs catalyst is greatly improved, and other transition metals have performance improving effects with different degrees.
FIG. 8 shows that 1FeO x The CNTs are inactive in formaldehyde elimination reaction, the 0.2Pt/CNTs catalyst achieves 100% conversion of formaldehyde at 40 ℃ and 0.2Pt-1FeO x The CNTs catalyst has excellent room temperature formaldehyde elimination performance, and can eliminate ppm formaldehyde completely at room temperature by converting formaldehyde 100% at 20-80 ℃.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A low-load Pt-based catalyst, which is characterized by comprising a carrier, a transition metal oxide and Pt;
the transition metal oxide is dispersed on the carrier in the form of nanometer islands; pt is selectively deposited and dispersed on the transition metal oxide nano islands under the action of a coupling agent;
based on the mass of the low-loading Pt-based catalyst, the contents of Pt and transition metal are respectively 0.05-0.5 wt% and 0.5-5 wt% based on the atomic mass.
2. The low-loading Pt-based catalyst of claim 1, wherein the carrier is a carbon nanotube; the transition metal oxide is at least one of Fe, ce, co, mn oxide.
3. The low loading Pt-based catalyst of claim 2, wherein the carbon nanotubes are multi-walled carbon nanotubes.
4. The low loading Pt-based catalyst of claim 1, wherein Pt is dispersed as 1-2 nm sized clusters on the transition metal oxide nanoislands.
5. A method of preparing a low loading Pt-based catalyst as claimed in any one of claims 1 to 4, comprising the steps of:
step 1: soaking carrier in transition metal M source solution, regulating pH value, stirring, aging, filtering, washing, drying, and roasting under inert atmosphere to obtain MO x A carrier;
step 2: dissolving a Pt source in low-carbon alcohol, mixing the Pt source with a strong alkali low-carbon alcohol solution, and reducing the mixture in an inert atmosphere to obtain Pt sol;
step 3: dispersing Pt sol in coupling agent and MO x And mixing the carriers, stirring, dipping, drying and reducing to obtain the low-load Pt-based catalyst.
6. The process according to claim 5, wherein in step 1, the concentration of the transition metal M source solution is 0.5 to 10X 10 -3 molL -1 。
7. The method according to claim 5, wherein in the step 2, the lower alcohol is at least one of ethylene glycol, glycerol, and 1, 4-butanediol.
8. The method according to claim 5, wherein in step 3, the coupling agent is at least one of aminosilane, carboxysilane, and triethanolamine.
9. Use of the low-loading Pt-based catalyst as claimed in any one of claims 1-4 in CO preferential oxidation reactions in hydrogen rich atmospheres, wherein the reaction temperature is 20-200 ℃.
10. Use of a low loading Pt-based catalyst as claimed in any one of claims 1 to 4 for formaldehyde abatement, wherein the reaction temperature is 20 to 80 ℃.
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