Cu modified V / Pt / TiO2 catalyst and preparation method thereof

Abstract

The invention provides a Cu modified V / Pt / TiO2 catalyst, a preparation method and application, and belongs to the field of industrial methanol removal and environmental protection, the carrier of the catalyst is TiO2, and the active components comprise vanadium pentoxide (V2O5), platinum (Pt) and copper oxide (CuOx). A two-step impregnation method is adopted for preparation, Pt / TiO2 is prepared through the first-step impregnation method, a Cu-V / Pt / TiO2 catalyst is prepared through the second-step impregnation method, and in the air atmosphere, the powdery SCO methanol removal catalyst is obtained through roasting. The raw materials used for preparing the catalyst are easy to obtain, and the process for preparing the catalyst is simple and convenient to operate; the catalyst has excellent methanol removal activity in a wide temperature range of 220-450 DEG C.

Description

Technical Field

[0001] The present invention relates to the field of SCO methanol removal catalysts, and particularly to a Cu-modified V / Pt / TiO2 catalyst, a preparation method thereof, and an application in the exhaust gas of marine methanol engines. Background Art

[0002] With the increasing shortage of energy resources and environmental protection issues, finding alternative clean fuels has become a top priority. Currently, for the shipping industry, using methanol as a marine fuel can significantly reduce the emissions of nitrogen oxides and particulate matter from ships. However, the escaped methanol in the exhaust gas of large slow-speed two-stroke marine methanol engines belongs to unconventional pollutants, which will greatly limit the large-scale application of methanol fuel engines in the shipping field in the future. SCO methanol removal is one of the most effective, economical, and feasible technologies, which can oxidize methanol into carbon dioxide, water, and other compounds with relatively less harm. Currently, both domestic and foreign are developing technologies for exhaust gas pollutants of methanol fuel engines, but no mature and available SCO catalyst products have been introduced. Therefore, developing a highly catalytically active SCO methanol removal catalyst is of great significance for ensuring that methanol fuel engines can meet international and regional emission standards, reducing potential legal and compliance risks, and promoting the green transformation of the global shipping industry. Summary of the Invention

[0003] The technical solution of the present invention provides a preparation method and application of a Cu-modified V / Pt / TiO2 catalyst for SCO methanol removal to solve the technical problems existing in the above background art.

[0004] To achieve the above object, the present invention provides a Cu-modified V / Pt / TiO2 catalyst, including a carrier and active components. The carrier is TiO2, and the active components include V2O5, Pt, and CuO x ;

[0005] In the catalyst, the weight ratio of Pt to the TiO2 carrier is 0.02 - 0.64%, the weight ratio of V2O5 to Pt / TiO2 is 0.25 - 3%, and CuO x The weight ratio to Pt / TiO2 is 0.25 - 2%.

[0006] Preferably, in the catalyst, the weight ratio of Pt to the TiO2 carrier is 0.04%, and the weight ratio of V2O5 to Pt / TiO2 is 0.5%.

[0007] Preferably, CuO x The precursor of is copper nitrate trihydrate, the precursor of V2O5 is ammonium metavanadate, and the precursor of Pt is platinum nitrate.

[0008] On the other hand, the present invention also provides a method for preparing a Cu-modified V / Pt / TiO2 catalyst, comprising the following steps:

[0009] (1) Dissolve platinum nitrate in deionized water to obtain a Pt precursor solution; add TiO2 powder, stir and evaporate the solvent in a water bath, and dry the obtained solid in an oven to obtain a dried platinum-titanium precursor sample; grind the dried platinum-titanium precursor sample into powder and then calcine it in a muffle furnace to obtain a platinum-titanium composite metal oxide powder;

[0010] (2) Dissolve oxalic acid and ammonium metavanadate in deionized water to obtain a V precursor solution, then add copper nitrate trihydrate, and then add the platinum-titanium composite metal oxide powder to the solution. Stir and evaporate the solvent in a water bath, and dry the obtained solid in an oven to obtain a Cu-modified V / Pt / TiO2 catalyst precursor sample. Finally, calcine the dried Cu-modified V / Pt / TiO2 catalyst precursor sample in a muffle furnace to obtain a Cu-modified V / Pt / TiO2 catalyst.

[0011] Preferably, in step (1), the weight ratio of the introduced Pt to the weight of TiO2 is 0.02-0.64%.

[0012] Preferably, in step (2), the introduced vanadium is calculated as V2O5, and its weight ratio to the weight of Pt / TiO2 is 0.25-3%; the introduced copper is calculated as CuO x and its weight ratio to the weight of Pt / TiO2 is 0.25-2%.

[0013] Preferably, in step (1), the specific process for preparing the platinum-titanium composite metal oxide is as follows: dissolve platinum nitrate in deionized water, stir for 5-10 min at a temperature of 20-40 °C, add titanium dioxide powder, stir for 2-4 h at a temperature of 20-40 °C, stir and evaporate the solvent in a water bath at 60-80 °C, place the obtained solid in an oven at 100-120 °C and dry for 6-8 h to obtain a platinum-titanium precursor sample. Finally, grind the dried platinum-titanium precursor sample into powder and then calcine it in a muffle furnace at a temperature of 500-550 °C for 3-5 h to obtain a platinum-titanium composite metal oxide powder.

[0014] Preferably, in step (2), the specific process of loading vanadium and copper is as follows: Oxalic acid and ammonium metavanadate are added to deionized water, and stirred for 5-10 min at a temperature of 20-40 °C to obtain a V precursor solution. Then, copper nitrate trihydrate is added, and stirred for 5-10 min at a temperature of 20-40 °C. Then, the platinum-titanium composite metal oxide powder prepared in step (1) is added to the solution, and stirred for 2-4 h at a temperature of 20-40 °C. The solvent is evaporated by stirring in a water bath at 60-80 °C. The obtained solid is dried in an oven at a temperature of 100-120 °C for 6-8 h to obtain a Cu-modified V / Pt / TiO2 catalyst precursor sample. Finally, the dried Cu-modified V / Pt / TiO2 catalyst precursor sample is calcined in a muffle furnace at a temperature of 500-550 °C for 3-5 h to obtain a Cu-modified V / Pt / TiO2 catalyst.

[0015] The present invention also provides an application of the Cu-modified V / Pt / TiO2 catalyst in the removal of methanol from the exhaust pollutants of marine methanol engines.

[0016] The beneficial technical effects of the present invention:

[0017] (1) The raw materials used in the preparation of the catalyst of the present invention are easily available, and the process for preparing the catalyst is simple and convenient to operate.

[0018] (2) The catalyst prepared in this application has good activity in a wide temperature range of 220 °C to 450 °C, and can achieve efficient and stable conversion of methanol.

[0019] (3) The catalyst obtained through the two-step calcination process has higher mechanical strength and better wear resistance, making it particularly suitable for industrial promotion.

[0020] The following will further illustrate the concept, specific structure and technical effects of the present invention with reference to the drawings, so as to fully understand the purpose, features and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the graph of the change of CH3OH conversion rate of the CH3OH-SCO reaction of the Cu 0.5 V 0.5 / Pt 0.04 / TiO2 catalyst and V 0.5 / Pt 0.04 / TiO2 catalyst with temperature;

[0022] Figure 2 is the Cu 0.5 V 0.5 / Pt 0.04 / TiO2 catalyst and V 0.5 / Pt 0.04Figure of the CO2 yield of the CH3OH-SCO reaction over the Cu-modified V / Pt / TiO2 catalyst as a function of temperature. Detailed implementation manners

[0023] The following introduces multiple preferred embodiments of the present invention with reference to the accompanying drawings of the specification to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0024] In the accompanying drawings, components with the same structure are denoted by the same numerical labels, and components with similar structures or functions everywhere are denoted by similar numerical labels. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. To make the illustration clearer, the thickness of some parts in the drawings is appropriately exaggerated.

[0025] The present invention provides a Cu-modified V / Pt / TiO2 catalyst, which includes a carrier and active components. The carrier is TiO2, and the active components include V2O5, Pt, and CuO. x ; the weight ratio of Pt to the TiO2 carrier in the catalyst is 0.02-0.64%, the weight ratio of V2O5 to Pt / TiO2 is 0.25-3%, and CuO x has a weight ratio to Pt / TiO2 of 0.25-2%.

[0026] Preferably, the precursor of CuO x is copper nitrate trihydrate, the precursor of V2O5 is ammonium metavanadate, and the precursor of Pt is platinum nitrate.

[0027] On the other hand, the present invention also provides a preparation method of a Cu-modified V / Pt / TiO2 catalyst, which includes the following steps:

[0028] (1) Dissolve platinum nitrate in deionized water to obtain a Pt precursor solution; add TiO2 powder, stir and evaporate the solvent in a water bath, and dry the obtained solid in an oven to obtain a dried platinum-titanium precursor sample; grind the dried platinum-titanium precursor sample into powder and then calcine it in a muffle furnace to obtain a platinum-titanium composite metal oxide powder.

[0029] (2) Dissolve oxalic acid and ammonium metavanadate in deionized water to obtain a V precursor solution, then add copper nitrate trihydrate, and then add the platinum-titanium composite metal oxide powder to the solution. Stir and evaporate the solvent in a water bath, and dry the obtained solid in an oven to obtain a Cu-modified V / Pt / TiO2 catalyst precursor sample. Finally, calcine the dried Cu-modified V / Pt / TiO2 catalyst precursor sample in a muffle furnace to obtain a Cu-modified V / Pt / TiO2 catalyst.

[0030] In step (1), the weight ratio of the introduced Pt to the weight of TiO2 is 0.02 - 0.64%; in step (2), the introduced vanadium is calculated as V2O5, and its weight ratio to the weight of Pt / TiO2 is 0.25 - 3%; the introduced copper is calculated as CuO x and its weight ratio to the weight of Pt / TiO2 is 0.25 - 2%.

[0031] In step (1), the specific process for preparing the platinum-titanium composite metal oxide is as follows: Dissolve platinum nitrate in deionized water, stir for 5 - 10 min at a temperature of 20 - 40°C, add titanium dioxide powder, stir for 2 - 4 h at a temperature of 20 - 40°C, stir and evaporate the solvent in a water bath at 60 - 80°C, place the obtained solid in an oven at 100 - 120°C and dry for 6 - 8 h to obtain a platinum-titanium precursor sample. Finally, grind the dried platinum-titanium precursor sample into powder and calcine it in a muffle furnace at a temperature of 500 - 550°C for 3 - 5 h to obtain platinum-titanium composite metal oxide powder.

[0032] In step (2), the specific process for loading vanadium and copper is as follows: Add oxalic acid and ammonium vanadate to deionized water, stir for 5 - 10 min at a temperature of 20 - 40°C to prepare a V precursor solution, then add copper nitrate trihydrate, stir for 5 - 10 min at a temperature of 20 - 40°C, and then add the platinum-titanium composite metal oxide powder prepared in step (1) to the solution, stir for 2 - 4 h at a temperature of 20 - 40°C, stir and evaporate the solvent in a water bath at 60 - 80°C, place the obtained solid in an oven at 100 - 120°C and dry for 6 - 8 h to obtain a Cu-modified V / Pt / TiO2 catalyst precursor sample. Finally, place the dried Cu-modified V / Pt / TiO2 catalyst precursor sample in a muffle furnace at a temperature of 500 - 550°C and calcine it for 3 - 5 h to obtain a Cu-modified V / Pt / TiO2 catalyst.

[0033] The present invention also provides an application of the Cu-modified V / Pt / TiO2 catalyst in the removal of methanol from the exhaust pollutants of marine methanol engines.

[0034] The following further elaborates the present invention in combination with specific embodiments.

[0035] Example 1

[0036] Accurately weigh 0.0044 g of platinum nitrate (Pt(NO3)2) solution and add it to 10 ml of deionized water. Stir (400 r / min) at 25 °C for 5 min to obtain a Pt precursor solution. Secondly, add 2 g of TiO2 powder to the Pt precursor solution and stir (800 r / min) at 25 °C for 2 h for impregnation. Stir and evaporate the solvent in a water bath at 80 °C. The obtained solid is placed in an oven at 120 °C and dried for 6 h to obtain a platinum-titanium precursor sample. Finally, the dried platinum-titanium precursor sample is ground into powder and then calcined in a muffle furnace at 500 °C for 3 h to obtain platinum-titanium composite metal oxide powder. Accurately weigh 0.055 g of oxalic acid and 0.026 g of ammonium vanadate and add them to 10 ml of deionized water. Stir (400 r / min) at 25 °C for 5 min to obtain a V precursor solution; add 0.0304 g of copper nitrate trihydrate to the V precursor solution, stir (400 r / min) at 25 °C for 5 min, then add 2 g of platinum-titanium composite metal oxide powder to the solution, stir (800 r / min) at 25 °C for 2 h for impregnation, stir and evaporate the solvent in a water bath at 80 °C. The obtained solid is dried in an oven at 120 °C for 6 h to obtain an SCO methanol dehydrogenation catalyst precursor sample. Finally, the dried SCO methanol dehydrogenation catalyst precursor sample is placed in a muffle furnace at 500 °C and calcined for 3 h. The obtained catalyst is denoted as Cu 0.5 V 0.5 / Pt 0.04 / TiO2。

[0037] Example 2

[0038] Accurately weigh 0.0044 g of platinum nitrate (Pt(NO3)2) solution and add it to 10 ml of deionized water. Stir (400 r / min) at 25 °C for 5 min to obtain a Pt precursor solution. Secondly, add 2 g of TiO2 powder to the Pt precursor solution and stir (800 r / min) at 25 °C for 2 h for impregnation. Stir and evaporate the solvent in a water bath at 80 °C. The obtained solid is placed in an oven at 120 °C and dried for 6 h to obtain a platinum-titanium precursor sample. Finally, the dried platinum-titanium precursor sample is ground into powder and then calcined in a muffle furnace at 500 °C for 3 h to obtain platinum-titanium composite metal oxide powder. Accurately weigh 0.055 g of oxalic acid and add it to 10 ml of deionized water, then add 2 g of platinum-titanium composite metal oxide powder to the solution, stir (800 r / min) at 25 °C for 2 h for impregnation, stir and evaporate the solvent in a water bath at 80 °C. The obtained solid is dried in an oven at 120 °C for 6 h to obtain an SCO methanol dehydrogenation catalyst precursor sample. Finally, the dried SCO methanol dehydrogenation catalyst precursor sample is placed in a muffle furnace at 500 °C and calcined for 3 h. The obtained catalyst is denoted as V 0.5 / Pt 0.04 / TiO2。

[0039] Application Examples

[0040] The prepared Cu 0.5 V 0.5 / Pt 0.04 / TiO2 and V 0.5 / Pt 0.04 / TiO2 catalysts were applied to the CH3OH-SCO reaction. The specific reaction conditions were as follows: The reaction was tested in a fixed-bed continuous-flow quartz reactor. The catalyst particle size was 40-60 mesh, and the dosage was 0.2 ml. The reaction gas composition (simulating the exhaust gas composition of an actual marine methanol engine) was 500 ppm CH3OH, 5 vol% O2, N2 carrier gas, the gas flow rate was 200 ml / min, and the space velocity was 60,000 h -1 , and the reaction temperature range of the catalyst was 150-450 °C. The products were detected and analyzed by a Fourier transform infrared flue gas analyzer (Intaris IGS). The CH3OH conversion rate and CO2 selectivity were calculated by the following formulas:

[0041]

[0042] Among them, [CH3OH] in represents the initial concentration of CH3OH, [CH3OH] out represents the CH3OH concentration at the outlet of the flue gas analyzer, and [CO2] out represents the CO2 concentration at the outlet of the flue gas analyzer.

[0043] Figure 1 is the graph of the change of CH3OH conversion rate with temperature in the CH3OH-SCO reaction of Cu 0.5 V 0.5 / Pt 0.04 / TiO2 catalysts and V 0.5 / Pt 0.04 / TiO2 catalysts; Figure 2 is the graph of the change of CH3OH conversion rate with temperature in the CH3OH-SCO reaction of Cu 0.5 V 0.5 / Pt 0.04 / TiO2 catalysts and V 0.5 / Pt 0.04Figure showing the variation of CO2 yield with temperature in the CH3OH-SCO reaction over the Cu-modified V / Pt / TiO2 catalyst. From the above activity results, it can be seen that for the Cu-modified V / Pt / TiO2 catalyst prepared in the present invention, the temperature range for the CH3OH conversion rate to reach 95% is 220 - 450 °C, and the temperature range for the CO2 yield to reach 95% is 222 - 450 °C; for the unmodified V / Pt / TiO2 catalyst, the temperature range for the CH3OH conversion rate to reach 95% is 320 - 450 °C, and the temperature range for the CO2 yield to reach 95% is 328 - 450 °C. Therefore, the Cu-modified V / Pt / TiO2 catalyst has higher methanol dehydrogenation activity.

[0044] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in the technical field based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art should fall within the protection scope determined by the claims.

Claims

1. A Cu-modified V / Pt / TiO₂ catalyst, characterized in that, It includes a carrier and an active component. The carrier is TiO2, and the active component includes V2O5, Pt, and CuO x ; The weight ratio of Pt to the TiO2 support in the catalyst is 0.02 to 0.64%, the weight ratio of V2O5 to Pt / TiO2 is 0.25 to 3%, and the weight ratio of CuO x to Pt / TiO2 is 0.25 to 2%.

2. The Cu-modified V / Pt / TiO2 catalyst according to claim 1, wherein The weight ratio of Pt to the TiO2 support in the catalyst is 0.04%, and the weight ratio of V2O5 to Pt / TiO2 is 0.5%.

3. The Cu-modified V / Pt / TiO2 catalyst according to claim 1, wherein CuO x The precursor of CuO is copper nitrate trihydrate, the precursor of V2O5 is ammonium vanadate, and the precursor of Pt is platinum nitrate.

4. A preparation method of a Cu-modified V / Pt / TiO2 catalyst, characterized in that, It includes the following steps: (1) Dissolve platinum nitrate in deionized water to obtain a Pt precursor solution; add TiO2 powder, stir and evaporate the solvent in a water bath, and dry the obtained solid in an oven to obtain a dried platinum-titanium precursor sample; grind the dried platinum-titanium precursor sample into powder and then calcine it in a muffle furnace to obtain a platinum-titanium composite metal oxide powder; (2) Dissolve oxalic acid and ammonium vanadate in deionized water to obtain a V precursor solution, then add copper nitrate trihydrate, and then add the platinum-titanium composite metal oxide powder to the solution. Stir and evaporate the solvent in a water bath, and dry the obtained solid in an oven to obtain a Cu-modified V / Pt / TiO2 catalyst precursor sample. Finally, calcine the dried Cu-modified V / Pt / TiO2 catalyst precursor sample in a muffle furnace to obtain a Cu-modified V / Pt / TiO2 catalyst.

5. The preparation method according to claim 4, characterized in that, In step (1), the weight ratio of the introduced Pt to TiO2 is 0.02 - 0.64%.

6. The preparation method according to claim 4, characterized in that In step (2), the introduced vanadium is calculated as V2O5, and the weight ratio of vanadium to Pt / TiO2 is 0.25-3%; the introduced copper is calculated as CuO x and the weight ratio of copper to Pt / TiO2 is 0.25-2%.

7. The preparation method according to claim 4, characterized in that In step (1), the specific process for preparing the platinum-titanium composite metal oxide is as follows: dissolve platinum nitrate in deionized water, stir for 5 - 10 min at a temperature of 20 - 40 °C, add titanium dioxide powder, stir for 2 - 4 h at a temperature of 20 - 40 °C, stir and evaporate the solvent in a water bath at 60 - 80 °C, place the obtained solid in an oven at 100 - 120 °C and dry for 6 - 8 h to obtain a platinum-titanium precursor sample. Finally, grind the dried platinum-titanium precursor sample into powder and then calcine it in a muffle furnace at a temperature of 500 - 550 °C for 3 - 5 h to obtain a platinum-titanium composite metal oxide powder.

8. The preparation method according to claim 4, wherein In step (2), the specific process for loading vanadium and copper is as follows: add oxalic acid and ammonium vanadate to deionized water, stir for 5 - 10 min at a temperature of 20 - 40 °C to obtain a V precursor solution, then add copper nitrate trihydrate, stir for 5 - 10 min at a temperature of 20 - 40 °C, and then add the platinum-titanium composite metal oxide powder prepared in step (1) to the solution, stir for 2 - 4 h at a temperature of 20 - 40 °C, stir and evaporate the solvent in a water bath at 60 - 80 °C, dry the obtained solid in an oven at a temperature of 100 - 120 °C for 6 - 8 h to obtain a Cu-modified V / Pt / TiO2 catalyst precursor sample. Finally, calcine the dried Cu-modified V / Pt / TiO2 catalyst precursor sample in a muffle furnace at a temperature of 500 - 550 °C for 3 - 5 h to obtain a Cu-modified V / Pt / TiO2 catalyst.

9. Application of a catalyst prepared by the preparation method of the Cu-modified V / Pt / TiO2 catalyst according to any one of claims 1 - 3 or the Cu-modified V / Pt / TiO2 catalyst according to any one of claims 4 - 8 in the removal of methanol from the exhaust pollutants of marine methanol engines.

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