Current auxiliary catalyst as well as preparation method and application thereof

Abstract

The invention provides a current-assisted catalyst as well as a preparation method and application thereof. The current-assisted catalyst comprises a semiconductor type transition metal oxide carrier and noble metal components distributed on the surface of the semiconductor type transition metal oxide carrier, the noble metal component is distributed on the surface of the semiconductor type transition metal oxide carrier in a cluster form. The noble metal components are loaded on the semiconductor type transition metal oxide carrier in a cluster form, and flowing charges are enriched on the surface of the catalyst under the assistance of current, so that efficient catalysis of CO and resistance to SO2 adsorption can be realized.

Description

Technical Field

[0001] The present invention relates to the field of air purification technology, specifically to the field of catalytic oxidation of gaseous pollutants, and in particular to a current-assisted catalyst and a preparation method and application thereof. Background Art

[0002] Due to the incomplete combustion of various carbon sources, industrial production and motor vehicle exhaust usually contain high concentrations of CO gas, which is harmful to human health and the ecological environment. Catalytic combustion of CO into CO2 is considered to be the most effective and energy-saving treatment method, but some exhaust gases containing CO also contain a certain amount of SO2 gas. SO2 will adsorb on the catalyst surface to form stable sulfates or strongly adsorb to occupy active sites, hindering the active sites of the catalyst from adsorbing CO or O2, and reducing the ability of the active sites to activate the adsorbed molecules through charge interactions, thereby inhibiting the adsorption and activation of CO, resulting in a decrease in the efficiency of the catalyst catalytic combustion of CO. At present, there are strategies such as coating the active sites of precious metals with molecular sieves to construct molecular fences to hinder SO2, enhancing the anti-sulfur performance of the catalyst, and increasing the action time of the catalyst in exhaust gases containing SO2.

[0003] CN116251586A discloses a method for preparing a sulfur-resistant CO oxidation catalyst, wherein a TiO2-SiO2 coating soaked in a pore-expanding solution is expanded by a microwave-assisted method, and the active component Pt is loaded on the expanded TiO2-SiO2 composite oxide coating by an impregnation method. The specific surface area and pore volume of the prepared catalyst are increased, the pore structure of the catalyst is optimized, and the sulfate generated by the impurity SO2 participating in the side reaction blocks the micropores of the catalyst and causes the catalyst to deactivate.

[0004] CN117085678A discloses an integral medium-low temperature water-resistant and sulfur-resistant CO oxidation catalyst and a preparation method thereof, comprising preparing a mixed precursor aqueous solution of Sn salt and Zr salt; impregnating a porous TiO2 carrier in the mixed precursor aqueous solution, and then drying and calcining the carrier for the first time to obtain a pretreated carrier; preparing a mixed solution of a Pt precursor and a surfactant, and then impregnating the pretreated carrier therein, and then drying and calcining the pretreated carrier for the second time to obtain the CO oxidation catalyst, which has good CO low-temperature oxidation activity and water and sulfur resistance.

[0005] CN107376935A discloses an integral catalyst for catalytic oxidation of CO at room temperature, comprising precious metal Pt as an active component, a composite metal oxide as an auxiliary coating, and a honeycomb ceramic as a carrier; the catalyst has high activity at room temperature, reduces the energy consumption of the CO removal process, has good water and sulfur resistance and stability, and can effectively remove CO under conditions of high air velocity, CO concentration and air volume changes, and is suitable for the room-temperature elimination of CO in various combustion exhaust gases and closed and semi-closed places.

[0006] In view of the problems existing in the prior art, it is of great significance to prepare a CO catalytic combustion catalyst that has the ability to resist SO2 and has high activity at low temperature. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention aims to provide a current-assisted catalyst and its preparation method and application. The present invention loads the precious metal components in the form of clusters onto a semiconductor-type transition metal oxide carrier with a narrow bandgap and good conductivity. With the assistance of current, the catalyst surface is enriched with mobile charges, which is conducive to achieving efficient catalysis of CO and resistance to SO2 adsorption.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a current-assisted catalyst, the current-assisted catalyst comprising a semiconductor-type transition metal oxide carrier and a noble metal component distributed on the surface of the semiconductor-type transition metal oxide carrier;

[0010] The noble metal components are distributed on the surface of the semiconductor-type transition metal oxide support in the form of clusters.

[0011] The present invention selects semiconductor-type transition metal oxides with narrow bandgap and good conductivity as carriers. Under the assistance of current, the surface of the semiconductor-type transition metal oxide carrier is enriched with mobile charges, which can effectively resist the adsorption of SO2, that is, it has excellent sulfur resistance. The highly active precious metal components are loaded on the semiconductor-type transition metal oxide carrier in the form of clusters. Under the action of mobile charges, the high activity of the precious metal components in catalytic oxidation of CO can be fully utilized, which is conducive to achieving efficient catalysis of CO at low temperature stage and resistance to SO2 adsorption. The current-assisted catalyst provided by the present invention can maintain a high catalytic efficiency in the process of catalytic combustion of CO, avoid the problem of decreased catalytic efficiency caused by adsorption of SO2, and has excellent anti-SO2 stability.

[0012] Preferably, the material of the semiconductor transition metal oxide support includes any one or a combination of at least two of V2O5, WO3, Co3O4, CuO, Cr2O3, TiO2, ZnO or MoO3. Typical but non-limiting combinations include V2O5 and ZnO, V2O5 and WO3, V2O5 and Co3O4, WO3 and Co3O4, CuO and ZnO, Cr2O3 and TiO2 or ZnO and MoO3. Preferably, it is any one or a combination of at least two of V2O5, WO3 or Co3O4, and more preferably WO3.

[0013] Preferably, the semiconductor transition metal oxide carrier further includes a doping element, and the doping element includes any one or a combination of at least two of Nb, Cu, Mo or Co. Typical but non-limiting combinations include Nb and Cu, Cu and Mo, Mo and Co or Mo and Nb.

[0014] In the present invention, the introduction of a specific type of doping element into the semiconductor-type transition metal oxide carrier is beneficial to the improvement of the electronic conductivity of the carrier and the improvement of the transmission efficiency of electrons in the current. If the content of the doping element is too little, the conductivity improvement is not obvious. If the content of the doping element is too high, the crystal form of the semiconductor-type transition metal oxide carrier will be changed, resulting in a significant decrease in the electronic conductivity of the carrier.

[0015] Preferably, in the semiconductor transition metal oxide carrier, the mass percentage of the doping element is 3%-10%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, the specific surface area of ​​the semiconductor transition metal oxide support is 5m 2 / g-40m 2 / g, for example, it can be 5m 2 / g, 10m 2 / g, 15m 2 / g, 20m 2 / g, 25m 2 / g, 30m 2 / g, 35m 2 / g or 40m 2 / g, including but not limited to the listed values, other values ​​not listed within the numerical range are also applicable.

[0017] In the present invention, the loading amount of the precious metal component should match the specific surface area of ​​the semiconductor transition metal oxide carrier, so that the precious metal component remains in the form of clusters rather than being dispersed in single atoms or forming large particles. If the mass percentage of the precious metal component is too small, the precious metal tends to be dispersed on the surface of the carrier in the form of single atoms, and the content of zero-valent precious metal is low, which is not conducive to the adsorption and activation of CO. If the mass percentage of the precious metal component is too large, the precious metal agglomerates into large particles, and a large amount of precious metal is in the inner layer of the particles and cannot be exposed as active sites, resulting in waste of precious metals.

[0018] Preferably, in the current-assisted catalyst, the mass percentage of the precious metal component is 0.5%-5%, for example, it can be 0.5%, 0.75%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 0.75%-2.5%.

[0019] Preferably, the precious metal component includes any one of Pt, Pd, Ru, Rh, Ag, Au or Ir or a combination of at least two of them. Typical but non-limiting combinations include Pt and Pd, Pd and Rh, Pt and Rh, Ag and Au or Ir and Ru, preferably any one of Pt, Pd or Rh or a combination of at least two of them.

[0020] In a second aspect, the present invention provides a method for preparing the current-assisted catalyst as described in the first aspect, the preparation method comprising:

[0021] A semiconductor-type transition metal oxide carrier and a noble metal precursor solution are mixed to react to obtain a current-assisted catalyst precursor, which is then calcined to obtain the current-assisted catalyst.

[0022] Preferably, the method of obtaining the current-assisted catalyst precursor by the reaction includes an impregnation method or a solvothermal method.

[0023] Preferably, the drying temperature of the impregnation method is 50°C-80°C, for example, it can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the temperature of the solvothermal method is 150°C-200°C, for example, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] The temperature at which the current-assisted catalyst is calcined in the present invention affects the electronic conductivity of the semiconductor-type transition metal oxide support. If the calcination temperature is too low, the semiconductor-type transition metal oxide support has insufficient crystallinity and poor electronic conductivity. If the calcination temperature is too high, the crystal form of the semiconductor-type transition metal oxide support will be changed, resulting in a decrease in conductivity.

[0026] Preferably, the calcination temperature is 200°C-600°C, for example, it can be 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C or 800°C, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the calcination time is 2h-8h, for example, 2h, 3h, 4h, 5h, 6h, 7h or 8h, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the method for preparing the semiconductor-type transition metal oxide support comprises:

[0029] A semiconductor type transition metal oxide precursor solution is prepared, a semiconductor type transition metal oxide carrier precursor is obtained by reaction, and the precursor is sintered to obtain the semiconductor type transition metal oxide carrier.

[0030] Preferably, the semiconductor-type transition metal oxide precursor includes any one of ammonium metavanadate, ammonium metatungstate, cobalt nitrate, copper nitrate, chromium nitrate, tetrabutyl titanate, zinc nitrate or ammonium metamolybdate, or a combination of at least two thereof. Typical but non-limiting combinations include ammonium metavanadate and cobalt nitrate, ammonium metatungstate and cobalt nitrate, copper nitrate and cobalt nitrate, chromium nitrate and tetrabutyl titanate, or zinc nitrate and ammonium metamolybdate.

[0031] Preferably, the semiconductor-type transition metal oxide precursor solution also includes any one or a combination of at least two of niobium chloride, copper nitrate, ammonium metamolybdate or cobalt nitrate. Typical but non-limiting combinations include niobium chloride and copper nitrate, ammonium metamolybdate and cobalt nitrate, or ammonium metamolybdate and niobium chloride.

[0032] Preferably, the method of obtaining the semiconductor-type transition metal oxide carrier precursor by the reaction includes any one of chemical coprecipitation, hydrothermal, solvothermal or sol-gel method, preferably chemical coprecipitation.

[0033] In the present invention, the semiconductor-type transition metal oxide carrier precursor is obtained by chemical precipitation reaction. For example, the semiconductor-type transition metal oxide carrier precursor can be obtained by adjusting the pH of the semiconductor-type transition metal oxide precursor solution to cause precipitation in the semiconductor-type transition metal oxide precursor solution.

[0034] In the present invention, the method for adjusting the pH of the semiconductor-type transition metal oxide precursor solution is not particularly limited. For example, nitric acid, hydrochloric acid, ammonia water, sodium bicarbonate, sodium hydroxide or potassium hydroxide can be used to adjust the pH of the semiconductor-type transition metal oxide precursor solution to the range specified in this application.

[0035] In the present invention, the method of obtaining the semiconductor-type transition metal oxide carrier precursor by solvothermal reaction can be, for example, a semiconductor-type transition metal oxide precursor solution can be subjected to solvothermal reaction at 140° C.-180° C. to obtain the semiconductor-type transition metal oxide carrier precursor. In the present invention, the temperature for conducting the solvothermal reaction can be, for example, 140° C., 150° C., 160° C., 170° C. or 180° C., including but not limited to the listed values.

[0036] In the present invention, the semiconductor-type transition metal oxide carrier precursor is obtained by a sol-gel reaction, for example, by aging the semiconductor-type transition metal oxide precursor sol to obtain a semiconductor-type transition metal oxide precursor gel, and drying at 50° C. to obtain the semiconductor-type transition metal oxide carrier precursor. In the present invention, the temperature for drying the semiconductor-type transition metal oxide precursor gel can be 50° C., 55° C., 60° C., 65° C., 70° C., 75° C. or 80° C., including but not limited to the listed values.

[0037] Preferably, the sintering temperature is 400°C-800°C, for example, it can be 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C or 800°C, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] Preferably, the sintering time is 4h-24h, for example, it can be 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h or 24h, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the precious metal precursor in the precious metal precursor solution includes any one of platinum nitrate, palladium nitrate, ruthenium trichloride, rhodium nitrate, silver nitrate, chloroauric acid or chloroiridic acid, or a combination of at least two thereof. Typical non-limiting combinations include platinum nitrate and palladium nitrate, ruthenium trichloride and rhodium nitrate, silver nitrate and chloroauric acid, or chloroiridic acid and platinum nitrate.

[0040] Preferably, in the precious metal precursor solution, the mass percentage of the precious metal element is 5%-15%, for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] In a third aspect, the present invention provides an application of the current-assisted catalyst as described in the first aspect, wherein the current-assisted catalyst is applied in the field of gas purification.

[0042] Preferably, the application of the current-assisted catalyst includes:

[0043] A direct current is applied to both ends of the current-assisted catalyst, and when the current is on, the gas to be treated is introduced to remove gaseous pollutants in the gas to be treated.

[0044] Preferably, the method of applying a direct current across the current-assisted catalyst includes:

[0045] Conductive metal filters are placed at both ends of the container filled with the current-assisted catalyst, and the conductive metal filters are connected to both ends of the DC power supply.

[0046] Preferably, the power of the DC power supply is 0.2W-10W, for example, it can be 0.2W, 0.4W, 0.6W, 0.8W, 1W, 2W, 3W, 4W, 5W, 6W, 7W, 8W, 9W or 10W, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] Preferably, the voltage of the DC power supply is 1V-300V, for example, it can be 1V, 3V, 5V, 7V, 9V, 11V, 13V, 15V, 20V, 40V, 60V, 80V, 100V, 150V, 200V, 250V or 300V, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] The current-assisted catalyst provided by the present invention has excellent SO2 resistance stability under the action of current.

[0049] The current-assisted catalyst defined in the present invention also has high catalytic activity in the low temperature stage. The temperature for removing gaseous pollutants in the gas to be treated using the current-assisted catalyst provided by the present invention can be 0°C-175°C, for example, it can be 0°C, 5°C, 10°C, 15°C, 20°C, 40°C, 50°C, 60°C, 80°C, 100°C, 120°C, 140°C, 160°C or 175°C, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 50°C-150°C.

[0050] The current-assisted catalyst defined in the present invention has excellent removal efficiency of CO in the treated gas. When the current-assisted catalyst provided in the present invention is used to remove gas pollutants in the treated gas, the space velocity of the gas to be treated is 10 mL / (h·g)-500000 mL / (h·g), for example, it can be 10 mL / (h·g), 100 mL / (h·g), 500 mL / (h·g), 1000 mL / (h·g), 5000 mL / (h·g), 10000 mL / (h·g), 2 ...). L / (h·g), 30000mL / (h·g), 40000mL / (h·g), 50000mL / (h·g), 100000mL / (h·g), 200000mL / (h·g), 300000mL / (h·g), 400000mL / (h·g) or 500000mL / (h·g), including but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable, preferably 10000mL / (h·g)-50000mL / (h·g).

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The present invention selects semiconductor transition metal oxides as semiconductor transition metal oxide carriers, and loads highly active noble metal components in the form of clusters onto semiconductor transition metal oxide carriers with narrow bandgap width and good conductivity. With the assistance of electric current, mobile charges are enriched on the surface of the semiconductor transition metal oxide carrier, which is conducive to achieving efficient catalysis of CO in the low temperature stage and resistance to SO2 adsorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a comparison chart of the anti-SO2 stability of the current-assisted catalyst in Application Example 1 of the present invention and Comparative Application Example 3. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0055] Example 1

[0056] This embodiment provides a current-assisted catalyst, including a sulfur-resistant WO3 carrier and Pt metal clusters distributed on the surface of the sulfur-resistant WO3 carrier, wherein the mass percentage of the Pt metal clusters is 1%.

[0057] The preparation method of the current-assisted catalyst comprises:

[0058] (1) Preparation of sulfur-resistant WO3 carrier by chemical precipitation method. Weigh 0.535g of ammonium metatungstate, dissolve it in 10ml of oxalic acid solution with an oxalic acid concentration of 10wt%, stir for 2h, drop 1mol / L nitric acid solution, adjust the pH to 2, produce a yellow precipitate, age for 12h, collect the precipitate by suction, wash it three times with ultrapure water, and dry it in an oven at 100℃ for 12h to obtain a sulfur-resistant WO3 carrier precursor. Grind the obtained sulfur-resistant WO3 carrier precursor into powder in an agate mortar, put it into a crucible, and calcine it in a muffle furnace at a heating rate of 5℃ / min for 4h to obtain a sulfur-resistant WO3 carrier. The specific surface area of ​​the sulfur-resistant WO3 carrier is 10m 2 / g.

[0059] (2) Preparation of current-assisted catalyst by solvothermal method. Take 50 mg of 10 wt% Pt content platinum nitrate aqueous solution, disperse it in 10 ml of dilute ammonia solution, and stir it evenly to obtain a mixed solution. Add the sulfur-resistant WO3 carrier obtained in step (1) to the above mixed solution, and carry out solvothermal reaction at 175°C to obtain a current-assisted catalyst precursor. After grinding the obtained current-assisted catalyst precursor in an agate mortar, the ground current-assisted catalyst precursor is placed in a crucible, and in a muffle furnace, the temperature is raised to 400°C at a heating rate of 5°C / min, and calcined for 2 hours to obtain the current-assisted catalyst.

[0060] Example 2

[0061] This embodiment provides a current-assisted catalyst, including a sulfur-resistant WO3 carrier and Pd metal clusters distributed on the surface of the sulfur-resistant WO3 carrier, wherein the mass percentage of the Pd metal clusters is 0.75%.

[0062] The preparation method of the current-assisted catalyst is the same as that of Example 1, except that in step (2), 50 mg of a platinum nitrate aqueous solution with a Pt content of 7.5 wt % is dispersed in 10 ml of a dilute ammonia solution.

[0063] Example 3

[0064] This embodiment provides a current-assisted catalyst, including a sulfur-resistant WO3 carrier and Rh metal clusters distributed on the surface of the sulfur-resistant WO3 carrier, wherein the mass percentage of the Rh metal clusters is 2.5%.

[0065] The preparation method of the current-assisted catalyst is the same as that of Example 1, except that 100 mg of an aqueous solution of rhodium nitrate with a Pt content of 12.5 wt % is dispersed in 10 ml of a dilute ammonia solution in step (2).

[0066] Example 4

[0067] This embodiment provides a current-assisted catalyst, including a sulfur-resistant Co3O4 carrier and Pt metal clusters distributed on the surface of the sulfur-resistant Co3O4 carrier, wherein the mass percentage of the Pt metal clusters is 1%.

[0068] The preparation method of the current-assisted catalyst comprises:

[0069] (1) Preparation of sulfur-resistant Co3O4 carrier by chemical precipitation method. Weigh 1.812g of cobalt nitrate hexahydrate, dissolve it in 50ml of water, add 20ml of 1mol / L sodium bicarbonate aqueous solution to precipitate the cobalt nitrate aqueous solution, collect the precipitate by suction, wash it three times with ultrapure water, and dry it in an oven at 95℃ for 13h to obtain a sulfur-resistant Co3O4 carrier precursor. Grind the obtained sulfur-resistant Co3O4 carrier precursor into powder in an agate mortar, put it into a crucible, and calcine it in a muffle furnace at 800℃ for 5h at a heating rate of 5℃ / min to obtain a sulfur-resistant Co3O4 carrier. The specific surface area of ​​the sulfur-resistant Co3O4 carrier is 25m 2 / g.

[0070] (2) Preparation of current-assisted catalyst by solvothermal method. Take 50 mg of 10 wt% Pt content platinum nitrate aqueous solution, disperse it in 10 ml of dilute ammonia solution, and stir it evenly to obtain a mixed solution. Add the sulfur-resistant Co3O4 carrier obtained in step (1) to the above mixed solution, and carry out solvothermal reaction at 150°C to obtain a current-assisted catalyst precursor. After grinding the obtained current-assisted catalyst precursor in an agate mortar, the ground current-assisted catalyst precursor is placed in a crucible, and in a muffle furnace, the temperature is raised to 200°C at a heating rate of 5°C / min, and calcined for 8 hours to obtain the current-assisted catalyst.

[0071] Example 5

[0072] This embodiment provides a current-assisted catalyst, including a sulfur-resistant Co3O4 carrier and Pd metal clusters distributed on the surface of the sulfur-resistant Co3O4 carrier, wherein the mass percentage of the Pd metal clusters is 1.25%.

[0073] The preparation method of the current-assisted catalyst is the same as that of Example 4, except that in step (2), 50 mg of a palladium nitrate aqueous solution having a Pt content of 12.5 wt % is dispersed in 10 ml of a dilute ammonia solution.

[0074] Example 6

[0075] This embodiment provides a current-assisted catalyst, including a sulfur-resistant Co3O4 carrier and Pd metal clusters distributed on the surface of the sulfur-resistant Co3O4 carrier, wherein the mass percentage of the Pd metal clusters is 2%.

[0076] The preparation method of the current-assisted catalyst is the same as that of Example 4, except that in step (2), 100 mg of an aqueous solution of rhodium nitrate containing 10 wt% Pt is dispersed in 10 ml of a dilute ammonia solution.

[0077] Example 7

[0078] This embodiment provides a current-assisted catalyst, including a sulfur-resistant V2O5 carrier and Pt metal clusters distributed on the surface of the sulfur-resistant V2O5 carrier, wherein the mass percentage of the Pt metal clusters is 1%.

[0079] The preparation method of the current-assisted catalyst comprises:

[0080] (1) Preparation of sulfur-resistant V2O5 carrier by chemical precipitation method. Weigh 0.643g of ammonium metavanadate and dissolve it in 50ml of dilute ammonia solution, add 20ml of 1mol / L nitric acid solution to precipitate the ammonium metavanadate aqueous solution, collect the precipitate by suction, wash it three times with ultrapure water, and dry it in an oven at 100℃ for 12h to obtain a sulfur-resistant V2O5 carrier precursor. Grind the obtained sulfur-resistant V2O5 carrier precursor into powder in an agate mortar, put it into a crucible, and calcine it in a muffle furnace at 400℃ for 4h at a heating rate of 5℃ / min to obtain a sulfur-resistant V2O5 carrier. The specific surface area of ​​the sulfur-resistant V2O5 carrier is 40m 2 / g.

[0081] (2) Preparation of current-assisted catalyst by solvothermal method. Take 50 mg of 10 wt% Pt content platinum nitrate aqueous solution, disperse it in 10 ml of dilute ammonia solution, and stir it evenly to obtain a mixed solution. Add the sulfur-resistant V2O5 carrier obtained in step (1) to the above mixed solution, and carry out solvothermal reaction at 150°C to obtain a current-assisted catalyst precursor. After grinding the obtained current-assisted catalyst precursor in an agate mortar, the ground current-assisted catalyst precursor is placed in a crucible, and in a muffle furnace, the temperature is raised to 600°C at a heating rate of 5°C / min, and calcined for 2 hours to obtain the current-assisted catalyst.

[0082] Example 8

[0083] This embodiment provides a current-assisted catalyst, including a sulfur-resistant V2O5 carrier and Pd metal clusters distributed on the surface of the sulfur-resistant V2O5 carrier, wherein the mass percentage of the Pd metal clusters is 0.5%.

[0084] The preparation method of the current-assisted catalyst is the same as that of Example 7, except that in step (2), 25 mg of a 10 wt % Pt aqueous solution of palladium nitrate is dispersed in 10 ml of a dilute ammonia solution.

[0085] Example 9

[0086] This embodiment provides a current-assisted catalyst, including a sulfur-resistant V2O5 carrier and Rh metal clusters distributed on the surface of the sulfur-resistant V2O5 carrier, wherein the mass percentage of the Rh metal clusters is 5%.

[0087] The preparation method of the current-assisted catalyst is the same as that of Example 7, except that in step (2), 250 mg of an aqueous solution of rhodium nitrate having a Pt content of 10 wt% is dispersed in 10 ml of a dilute ammonia solution.

[0088] Example 10

[0089] This embodiment provides a current-assisted catalyst, including a Nb-doped sulfur-resistant TiO2 carrier and Pt metal clusters distributed on the surface of the Nb-doped sulfur-resistant TiO2 carrier, the mass percentage of Nb in the sulfur-resistant TiO2 carrier is 5%, and the mass percentage of the Pt metal clusters is 1%.

[0090] The preparation method of the current-assisted catalyst comprises:

[0091] (1) Preparation of Nb-doped sulfur-resistant TiO2 carrier by sol-gel method. 2.00 mL of tetrabutyl titanate and 0.837 g of niobium pentachloride were dissolved in 25 mL of ethanol to obtain a mixed solution, which was then added dropwise to 125 mL of ultrapure water. The pH was adjusted to 1.5 using nitric acid to obtain a Nb-doped sulfur-resistant TiO2 precursor sol. After stirring for 24 h, an aged Nb-doped sulfur-resistant TiO2 precursor gel was obtained. The aged Nb-doped sulfur-resistant TiO2 precursor gel was evaporated at 50 ° C in a rotary evaporator and dried at 70 ° C to obtain a Nb-doped sulfur-resistant TiO2 carrier precursor. The obtained Nb-doped sulfur-resistant TiO2 carrier precursor was ground into powder in an agate mortar, put into a crucible, and calcined in a muffle furnace at 400°C for 4 hours at a heating rate of 5°C / min to obtain a Nb-doped sulfur-resistant TiO2 carrier having a specific surface area of ​​50 m 2 / g.

[0092] (2) Preparation of current-assisted catalyst by impregnation heat method. Take 50 mg of 10 wt% Pt content platinum nitrate aqueous solution, disperse it in 10 ml of dilute ammonia solution, and stir evenly to obtain a mixed solution. Add the Nb-doped sulfur-resistant TiO2 carrier obtained in step (1) to the above mixed solution, stir and evaporate to dryness at 65°C to obtain a current-assisted catalyst precursor. After grinding the obtained current-assisted catalyst precursor in an agate mortar, put the ground current-assisted catalyst precursor in a crucible, and heat it to 400°C in a muffle furnace at a heating rate of 5°C / min, and calcine for 2 hours to obtain the current-assisted catalyst.

[0093] Embodiment 11

[0094] This embodiment provides a current-assisted catalyst, including a Cu-doped sulfur-resistant TiO2 carrier and Pd metal clusters distributed on the surface of the Cu-doped sulfur-resistant TiO2 carrier, the mass percentage of Cu in the sulfur-resistant TiO2 carrier is 3%, and the mass percentage of the Pd metal clusters is 1%.

[0095] The preparation method of the current-assisted catalyst is the same as that of Example 10, except that 0.837 g of niobium pentachloride in step (1) is replaced by 0.4988 g of copper nitrate, and the platinum nitrate aqueous solution in step (2) is replaced by palladium nitrate aqueous solution.

[0096] Example 12

[0097] This embodiment provides a current-assisted catalyst, including a Mo-doped sulfur-resistant TiO2 carrier and Rh metal clusters distributed on the surface of the Mo-doped sulfur-resistant TiO2 carrier, the mass percentage of Mo in the sulfur-resistant TiO2 carrier is 10%, and the mass percentage of the Rh metal clusters is 1%.

[0098] The preparation method of the current-assisted catalyst is the same as that of Example 10, except that 0.837 g of niobium pentachloride in step (1) is replaced by 1.2412 g of ammonium metamolybdate, and the platinum nitrate aqueous solution in step (2) is replaced by rhodium nitrate aqueous solution.

[0099] Embodiment 13

[0100] This embodiment provides a current-assisted catalyst, including a sulfur-resistant WO3 carrier and Pt metal clusters distributed on the surface of the sulfur-resistant WO3 carrier, wherein the mass percentage of the Pt metal clusters is 0.25%.

[0101] The preparation method of the current-assisted catalyst is the same as that of Example 1, except that in step (2), 1.25 mg of a 10 wt% Pt aqueous solution of platinum nitrate is dispersed in 10 ml of a dilute ammonia solution.

[0102] Embodiment 14

[0103] This embodiment provides a current-assisted catalyst, including a sulfur-resistant WO3 carrier and Pt metal clusters distributed on the surface of the sulfur-resistant WO3 carrier, wherein the mass percentage of the Pt metal clusters is 6%.

[0104] The preparation method of the current-assisted catalyst is the same as that of Example 1, except that 300 mg of an aqueous solution of platinum nitrate having a Pt content of 10 wt % is dispersed in 10 ml of a dilute ammonia solution in step (2).

[0105] Embodiment 15

[0106] This embodiment provides a current-assisted catalyst, including a Nb-doped sulfur-resistant TiO2 carrier and Pt metal clusters distributed on the surface of the Nb-doped sulfur-resistant TiO2 carrier, the mass percentage of Nb in the sulfur-resistant TiO2 carrier is 2%, and the mass percentage of the Pt metal clusters is 1%.

[0107] The preparation method of the current-assisted catalyst is the same as that of Example 10, except that 0.837 g of niobium pentachloride in step (1) is replaced by 0.3245 g of niobium chloride.

[0108] Example 16

[0109] This embodiment provides a current-assisted catalyst, including a Nb-doped sulfur-resistant TiO2 carrier and Pt metal clusters distributed on the surface of the Nb-doped sulfur-resistant TiO2 carrier, the mass percentage of Nb in the sulfur-resistant TiO2 carrier is 12%, and the mass percentage of the Pt metal clusters is 1%.

[0110] The preparation method of the current-assisted catalyst is the same as that of Example 10, except that 0.837 g of niobium pentachloride in step (1) is replaced by 2.168 g of niobium chloride.

[0111] Embodiment 17

[0112] This embodiment provides a current-assisted catalyst. The preparation method of the current-assisted catalyst is the same as that of Embodiment 1 except that the calcination temperature in step (2) is 150° C.

[0113] Embodiment 18

[0114] This embodiment provides a current-assisted catalyst. The preparation method of the current-assisted catalyst is the same as that of Embodiment 1 except that the calcination temperature in step (2) is 750° C.

[0115] Comparative Example 1

[0116] This comparative example provides a current-assisted catalyst, which is the same as Example 1 except that the semiconductor-type transition metal oxide carrier is aluminum oxide.

[0117] The preparation method of the current-assisted catalyst is the same as that of Example 1 except that the alumina carrier is added to the mixed solution in step (2).

[0118] Comparative Example 2

[0119] This comparative example provides a current-assisted catalyst, which is the same as Example 1 except that Pt is distributed in the form of single atoms on the surface of the sulfur-resistant WO3 carrier.

[0120] Application Example 1

[0121] This application example provides a method for using a current-assisted catalyst, including:

[0122] Take 0.05g of the current-assisted catalyst provided in Example 1 and put it into a container. Fill the container with porous conductive copper filters at both ends. The two ends of the conductive copper filter are connected to electrodes, and the electrodes are connected to the positive and negative poles of a DC power supply. The output power of the DC power supply is 4W and the output voltage is 150V.

[0123] Application Example 2

[0124] This application example provides a method for using a current-assisted catalyst, which is the same as application example 1 except that 0.05 g of the current-assisted catalyst provided in Example 2 is placed in a container.

[0125] Application Example 3

[0126] This application example provides a method for using a current-assisted catalyst. Except for taking 0.05 g of the current-assisted catalyst provided in Example 3 and putting it into a container, the rest is the same as that of Application Example 1.

[0127] Application Example 4

[0128] This application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that 0.1 g of the current-assisted catalyst provided in Example 4 is placed in a container, the output power of the DC power supply is 0.5 W, and the output voltage is 20 V.

[0129] Application Example 5

[0130] This application example provides a method for using a current-assisted catalyst. Except for taking 0.1 g of the current-assisted catalyst provided in Example 5 and putting it into a container, the rest is the same as that of Application Example 1.

[0131] Application Example 6

[0132] This application example provides a method for using a current-assisted catalyst. Except for taking 0.1 g of the current-assisted catalyst provided in Example 6 and putting it into a container, the rest is the same as that of Application Example 1.

[0133] Application Example 7

[0134] This application example provides a method for using a current-assisted catalyst. Except that 3 g of the current-assisted catalyst provided in Example 7 is placed in a container, the output power of the DC power supply is 4W, and the output voltage is 200V, everything else is the same as Application Example 1.

[0135] Application Example 8

[0136] This application example provides a method for using a current-assisted catalyst. Except for putting 3 g of the current-assisted catalyst provided in Example 8 into a container, the rest is the same as that of Application Example 1.

[0137] Application Example 9

[0138] This application example provides a method for using a current-assisted catalyst. Except for putting 3 g of the current-assisted catalyst provided in Example 9 into a container, the rest is the same as that of Application Example 1.

[0139] Application Example 10

[0140] This application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that 5 g of the current-assisted catalyst provided in Example 10 is placed in a container, the output power of the DC power supply is 6W, and the output voltage is 200V.

[0141] Application Example 11

[0142] This application example provides a method for using a current-assisted catalyst. Except for taking 5 g of the current-assisted catalyst provided in Example 11 and putting it into a container, the rest is the same as Application Example 1.

[0143] Application Example 12

[0144] This application example provides a method for using a current-assisted catalyst. Except for taking 5 g of the current-assisted catalyst provided in Example 12 and putting it into a container, the rest is the same as Application Example 1.

[0145] Application Example 13

[0146] This application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that 0.05 g of the current-assisted catalyst provided in Example 13 is placed in a container.

[0147] Application Example 14

[0148] This application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that 0.05 g of the current-assisted catalyst provided in Example 14 is placed in a container.

[0149] Application Example 15

[0150] This application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that 0.05 g of the current-assisted catalyst provided in Example 15 is placed in a container.

[0151] Application Example 16

[0152] This application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that 0.05 g of the current-assisted catalyst provided in Example 16 is placed in a container.

[0153] Application Example 17

[0154] This application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that 0.05 g of the current-assisted catalyst provided in Example 17 is placed in a container.

[0155] Application Example 18

[0156] This application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that 0.05 g of the current-assisted catalyst provided in Example 18 is placed in a container.

[0157] Comparative application example 1

[0158] This comparative application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that 0.05 g of the current-assisted catalyst provided in Comparative Example 1 is placed in a container.

[0159] Comparative Application Example 2

[0160] This comparative application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that 0.05 g of the current-assisted catalyst provided in Comparative Example 2 is placed in a container.

[0161] Comparative Application Example 3

[0162] This comparative application example provides a method for using a current-assisted catalyst, which is the same as Application Example 1 except that a direct current is not applied to the current-assisted catalyst provided in Example 1.

[0163] Comparative Application Example 4

[0164] This comparative application example provides a method for using a current-assisted catalyst, which is the same as Application Example 7 except that a direct current is not applied to the current-assisted catalyst provided in Example 7.

[0165] Performance Test:

[0166] (1) According to the use methods provided in all the above application examples and comparative application examples, the current-assisted catalysts provided in all the embodiments of the present invention and the comparative examples were tested for CO catalytic combustion performance:

[0167] Under the condition of space velocity of 30000mL / (g·h), the CO catalytic activity and anti-SO2 activity of the current-assisted catalyst were tested at 50℃, 75℃, 100℃, 125℃ and 150℃ respectively.

[0168] In the present invention, CO catalytic activity refers to the conversion rate of CO into CO2; anti-SO2 activity refers to the conversion rate of CO into CO2 in the presence of a certain concentration of sulfur dioxide.

[0169] The test results are shown in Table 1 and Table 2 respectively.

[0170] (2) The CO content in the gas to be treated was adjusted to 10000 ppm, the SO2 content was adjusted to 200 ppm, the O2 content was adjusted to 20%, and the N2 content was adjusted to balance. At 150°C and a space velocity of 15000 mL / (g·h), the anti-SO2 stability of the current-assisted catalysts provided in Application Example 1 and Comparative Application Example 3 was tested, that is, the stability of the CO catalytic activity of the current-assisted catalysts over time. The test results are shown in FIG. Figure 1 .

[0171] Table 1

[0172]

[0173]

[0174] Table 2

[0175]

[0176]

[0177] According to the test results of Application Examples 1 to 12, the present invention selects semiconductor transition metal oxides as carriers, and loads highly active precious metal components in the form of clusters onto semiconductor transition metal oxide carriers with a narrow bandgap and good conductivity. With the assistance of electric current, the catalyst surface is enriched with mobile charges, which is beneficial to achieving efficient catalysis of CO in the low-temperature stage and resistance to SO2 adsorption.

[0178] According to the test results of Application Example 1 and Comparative Application Example 1, if alumina, a non-semiconductor transition metal oxide, is selected as a carrier of the current-assisted catalyst, alumina does not have a narrow bandgap and good conductivity, and therefore cannot enrich mobile charges on the surface of the current-assisted catalyst, resulting in a significant decrease in the activity of catalytic oxidation of CO and resistance to SO2 adsorption.

[0179] According to the test results of Application Example 1 and Comparative Application Example 2, if the precious metal is dispersed on the surface of the semiconductor-type transition metal oxide support in the form of single atoms, rather than in the form of clusters as in the present invention, the activity of the prepared current-assisted catalyst in catalytic oxidation of CO is also significantly reduced.

[0180] According to the test results of Application Example 1 and Comparative Application Example 3 as well as Application Example 7 and Comparative Application Example 4, the current-assisted catalyst prepared by the present invention can enrich mobile charges on the catalyst surface under the action of electric current, thereby achieving high catalytic combustion activity of CO and resistance to SO2 in the low-temperature stage. If the electric current is not applied, the catalytic efficiency of CO and the resistance to SO2 are significantly reduced.

[0181] According to the test results of Application Example 1 and Application Examples 13 to 14, if the loading amount of the precious metal component on the surface of the semiconductor-type transition metal oxide carrier is too small, the CO low-temperature oxidation activity of the current-assisted catalyst is poor. If the loading amount of the precious metal component is too large, the excess precious metal cannot be fully utilized, resulting in waste of precious metals.

[0182] According to the test results of Application Example 1 and Application Examples 15 to 16, if the content of the doping element in the semiconductor-type transition metal oxide carrier is too little, the conductivity of the semiconductor-type transition metal oxide carrier will not be significantly improved. If the doping element is excessive, the crystal form of the semiconductor-type transition metal oxide carrier will change, reducing the electronic conductivity of the carrier.

[0183] According to the test results of Application Example 1 and Application Examples 17 to 18, if the calcination temperature when the semiconductor-type transition metal oxide support is combined with the precious metal in step (2) is too high, it will cause the crystal form of the semiconductor-type transition metal oxide support to change, affecting the electronic conductivity of the semiconductor-type transition metal oxide support. If the calcination temperature is too low, the semiconductor-type transition metal oxide support will have insufficient crystallinity and poor electronic conductivity.

[0184] like Figure 1 As shown, at 150° C., when the gas to be treated contains 200 ppm SO 2 , the current-assisted catalyst provided by the present invention maintains high catalytic combustion activity for CO and has excellent stability against SO 2 .

[0185] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A current-assisted catalyst, characterized in that: The current-assisted catalyst comprises a semiconductor-type transition metal oxide carrier and a noble metal component distributed on the surface of the semiconductor-type transition metal oxide carrier; The noble metal components are distributed on the surface of the semiconductor-type transition metal oxide support in the form of clusters.

2. The current-assisted catalyst according to claim 1, characterized in that The material of the semiconductor transition metal oxide carrier includes any one or a combination of at least two of V2O5, WO3, Co3O4, CuO, Cr2O3, TiO2, ZnO or MoO3, preferably any one or a combination of at least two of V2O5, WO3 or Co3O4, more preferably WO3; Preferably, the semiconductor-type transition metal oxide carrier further includes a doping element, and the doping element includes any one or a combination of at least two of Nb, Cu, Mo, or Co; Preferably, in the semiconductor-type transition metal oxide carrier, the mass percentage of the doping element is 3%-10%.

3. The current-assisted catalyst according to claim 1 or 2, characterized in that: The specific surface area of ​​the semiconductor transition metal oxide carrier is 5m 2 / g-40m 2 / g.

4. The current-assisted catalyst according to claim 3, characterized in that: In the current-assisted catalyst, the mass percentage of the precious metal component is 0.5%-5%, preferably 0.75%-2.5%; Preferably, the precious metal component includes any one or a combination of at least two of Pt, Pd, Ru, Rh, Ag, Au or Ir, preferably any one or a combination of at least two of Pt, Pd or Rh.

5. A method for preparing a current-assisted catalyst as claimed in any one of claims 1 to 4, characterized in that: The preparation method comprises: A semiconductor-type transition metal oxide carrier and a noble metal precursor solution are mixed to react to obtain a current-assisted catalyst precursor, which is then calcined to obtain the current-assisted catalyst.

6. The preparation method according to claim 5, characterized in that: The method of obtaining the current-assisted catalyst precursor by the reaction includes an impregnation method or a solvothermal method; Preferably, the drying temperature of the impregnation method is 50°C-80°C; Preferably, the temperature of the solvothermal method is 150°C-200°C; Preferably, the calcination temperature is 200°C-600°C; Preferably, the calcination time is 2h-8h.

7. The preparation method according to claim 5 or 6, characterized in that: The preparation method of the semiconductor-type transition metal oxide carrier comprises: Preparing a semiconductor transition metal oxide precursor solution, reacting to obtain a semiconductor transition metal oxide support precursor, and sintering to obtain the semiconductor transition metal oxide support; Preferably, the semiconductor-type transition metal oxide precursor includes any one or a combination of at least two of ammonium metavanadate, ammonium metatungstate, cobalt nitrate, copper nitrate, chromium nitrate, tetrabutyl titanate, zinc nitrate or ammonium metamolybdate; Preferably, the semiconductor-type transition metal oxide precursor solution further comprises any one or a combination of at least two of niobium chloride, copper nitrate, ammonium metamolybdate or cobalt nitrate; Preferably, the method of obtaining the semiconductor-type transition metal oxide carrier precursor by the reaction includes any one of a chemical coprecipitation method, a solvothermal method or a sol-gel method, preferably a chemical coprecipitation method; Preferably, the sintering temperature is 400°C-800°C; Preferably, the sintering time is 4h-24h.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The noble metal precursor in the noble metal precursor solution includes any one of platinum nitrate, palladium nitrate, ruthenium trichloride, rhodium nitrate, silver nitrate, chloroauric acid or chloroiridic acid, or a combination of at least two thereof; Preferably, in the noble metal precursor solution, the mass percentage of the noble metal element is 5%-15%.

9. A use of the current-assisted catalyst according to any one of claims 1 to 3, characterized in that: The current-assisted catalyst is used in the field of gas purification.

10. The use of the current-assisted catalyst as claimed in claim 9, characterized in that: The application method of the current-assisted catalyst includes: Applying a direct current to both ends of the current-assisted catalyst, and introducing a gas to be treated in a current-conducting state to remove gaseous pollutants in the gas to be treated; Preferably, the method of applying a direct current across the current-assisted catalyst includes: Conductive metal filters are placed at both ends of the container filled with the current-assisted catalyst, and the conductive metal filters are connected to both ends of the DC power supply respectively; Preferably, the power of the DC power supply is 0.2W-10W; Preferably, the voltage of the DC power supply is 1V-300V.

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