Antitoxic denitration catalyst as well as preparation method and application thereof

Abstract

The invention provides an anti-toxic denitration catalyst and a preparation method and application thereof, and belongs to the field of environmental protection and environmental catalysis, foam metal copper is used as a carrier, a copper-containing Ni-W-P-Se oxide is used as an active component, the active component is loaded on the foam copper carrier by adopting an electrochemical means, and the anti-toxic denitration catalyst is prepared. And the copper active component is diffused to the surface of the surface active component through a heat treatment means, so that the low-temperature denitration efficiency of the catalyst can be remarkably improved, the denitration catalyst is excellent in sulfur resistance and water resistance, and extremely high stability and restorability are kept.

Description

Technical Field

[0001] The invention relates to a denitration catalyst, in particular to a poison-resistant denitration catalyst and a preparation method and application thereof. The catalyst is suitable for the field of NH3 selective catalytic reduction of nitrogen oxides at low temperature and belongs to the field of environmental protection and environmental catalysis. Background Art

[0002] With the rapid development of economy, the sharp consumption of energy, the continuous deterioration of ecological environment, the sustainable development of society is facing great challenges. Among them, atmospheric dust and pollution are one of the four major global public hazards, and nitrogen oxides (NOx) are one of the main components of atmospheric environmental pollution. Therefore, how to reduce the generation and emission of nitrogen oxides in production and life is a problem that must be solved in today's society, which is of great practical significance for improving atmospheric environmental pollution.

[0003] Among nitrogen oxides, atmospheric pollutants mainly include nitric oxide (NO) and nitrogen dioxide (NO2). NO2 is stable and its toxicity is about 4-5 times that of NO. NO is unstable and after being emitted into the atmosphere, it is easily oxidized by O2 or O3 in the atmosphere to become stable NO. x When they enter the atmosphere together, a series of physical and chemical reactions will occur in the atmosphere, causing very serious environmental problems such as acid rain and photochemical smog. x The concentration of NO increases year by year, which not only causes extremely serious environmental problems in nature, but also has great harm to human health and the survival of animals and plants. x The governance of this issue is imminent and has received widespread attention from scholars at home and abroad. The current research is mainly focused on SCR denitrification technology for coal-fired power plants. For coal-fired thermal power units, the NH3-SCR denitrification technology based on vanadium-titanium catalysts is currently used. Its reaction mechanism is very complex. In simple terms, it mainly uses NH3 as a reducing agent to "selectively" react with NOx in the flue gas at a certain temperature to reduce it to non-toxic and non-polluting N2 and H2O.

[0004] Standard SCR reaction: 4NH3+4NO+O2→4N2+6H2O; fast SCR reaction: 4NH3+2NO2+2NO→4N2+6H2O; slow SCR reaction: 8NH3+6NO2→7N2+12H2O; in the case of insufficient or no O2, the NH3-SCR process may also undergo the following reaction: 4NH3+6NO→5N2+6H2O. In actual applications, due to the presence of excess O2 in the flue gas, the reducing agent NH3 will undergo side reactions to produce adverse by-products, while reducing the activity of the catalyst.

[0005] In addition, under the condition of SO2 and H2O, the SCR system may also have the following side reactions: 2SO2+O2→2SO3; SO2+H2O→H2SO4; 2NH3+SO3+H2O→(NH4)2SO4; NH3+SO3+H2O→NH4H S O4; When the temperature reaches 350℃ and above, the decomposition and oxidation reactions of NH3 begin to occur. When the temperature exceeds 450℃, the reaction will be very intense. Therefore, in general SCR processes, the reaction temperature is usually controlled below 450℃. At the same time, the adverse side reactions between SO2, H2O and NH3 usually occur below 350℃. In order to avoid such side reactions, the SCR denitrification system is usually arranged before the dust collector. At this time, the optimal operating temperature of the catalyst is 300-400℃. However, under such operating conditions, the catalyst has defects such as frequent maintenance, short life, and easy poisoning and deactivation. In the NH3-SCR reaction process, the catalyst is the core of the entire reaction. The selection of the catalyst determines the NO X The denitrification efficiency, active temperature window, stability and resistance to H2O / SO2 poisoning are improved. NH3-SCR catalysts mainly include precious metal catalysts, ion exchange zeolite molecular sieve catalysts and metal oxide catalysts.

[0006] Precious metal catalysts have unfilled d electron orbitals, which easily adsorb reactants on the surface, which is conducive to the formation of intermediate "active compounds" with high catalytic activity. They also have advantages such as anti-oxidation and corrosion resistance, making them the most important catalyst materials. However, the high cost and narrow activity window of precious metal catalysts have hindered the development of NH3-SCR reaction process.

[0007] Ion exchange zeolite molecular sieve catalysts have a unique framework structure and acid-base centers, which are conducive to the SCR reaction process. For mobile source denitrification, SCR systems have been increasingly used in diesel vehicles, and three-way catalytic converter technology has made great contributions to the elimination of CO, HC and NOx in gasoline-powered vehicles. Commercial vanadium-based catalysts are not suitable for use in diesel engines due to their narrow temperature window and poor hydrothermal durability. X Therefore, molecular sieve catalysts are becoming more and more attractive in mobile source NH3-SCR applications. Some transition metal oxides have been explored in low-temperature NH3-SCR reactions because of their low price, high thermodynamic stability and good anti-poisoning ability. In addition, the d electron layer of the metal cation in the transition metal oxide can easily gain and lose electrons, giving it excellent redox properties. Summary of the invention

[0008] The present invention provides a poison-resistant denitration catalyst and a preparation method and application thereof. The catalyst has high low-temperature activity and high selectivity, and the catalyst has extremely high resistance to SO2 and H2O poisoning.

[0009] A method for preparing a toxic-resistant denitration catalyst, wherein the denitration catalyst uses foam copper as a substrate, and Ni-WP-Se oxide is in-situ attached to the surface, wherein the oxide morphology at least includes a rod-like structure. The catalyst is prepared by the following steps: (1) Surface pretreatment of copper foam: Take copper foam of appropriate size and immerse it in acetone, ethanol and deionized water for ultrasonic cleaning in turn. The total ultrasonic cleaning time shall not exceed 40 minutes. Then, immerse it in 1.2-1.5 mol / L hydrochloric acid aqueous solution for 3-5 minutes. After taking it out, wash it with deionized water until it is neutral, and dry it at 80-100°C. (2) Electrochemical in-situ deposition of active components: The copper foam prepared in step (1) is used as the cathode and the inert metal is used as the anode, and they are immersed in an electroplating solution, wherein the electrolyte is composed of 60-70 g / L nickel nitrate, 40-50 g / L nickel tungstate, 20-22 g / L sodium hypophosphite, 10-15 g / L Na2SeO4, 110-120 g / L tartaric acid, 30 ml / L ammonia water and deionized water, wherein the ammonia water is a pH regulator, and the pH value of the electroplating solution is adjusted to 5.5-6.5. The electrolysis parameters are: temperature 60-65 ° C, current density 3-5 A / dm 2 , time is 10-15min; (3) Heat treatment: Place the copper foam treated with electrochemical in-situ deposition of active components directly in a tubular furnace, heat it to 60-70°C at 2°C / min and keep it at that temperature for 24-48 hours, then heat it to 300-350°C at 1-2°C and keep it at that temperature for 1-2 hours, and cool it naturally to obtain a toxic-resistant denitrification catalyst.

[0010] The catalytic activity of the copper foam as a substrate is much higher than that of the nickel foam or the iron foam.

[0011] Air or 10 vol.% O2 / N2 mixed gas is introduced into the tubular furnace, and the gas introduced is a non-pure inert gas or a non-reducing gas.

[0012] NH3-SCR was tested for performance using 3.5g of copper foam catalyst (copper foam + surfactant) in a fixed bed quartz reactor (15mm inner diameter). The simulated flue gas system contained 1000ppmNH3, 1000ppmNO, 3vol.% O2, 10vol.%H2O (when used), 100ppmSO2 (when used) and N2 as the balance gas. The GHSV (ratio of the raw material volume flow rate to the catalyst volume per unit time) was 40000h-1 The concentrations of reactants and products were determined online using a mass spectrometer (QIC-20) and a NO / NOx analyzer (Switzerland ECOphysics). Each test was conducted until the NH3-SCR reaction reached a steady state. The selectivity and conversion were calculated according to the following formula. NO conversion rate (%) = ([NO] in -[NO] out ) / [NO] in *100%.

[0013] NO selectivity (%) = [1- {(2[N2O] out + [NO2] out ) / ( [NO] in +[NH3] in -[NO] out -[NH3] out ])}】*100% Where [NO] in and [NO] out represent the NO concentration inside and outside the reactor, respectively; [NO2]out and [N2O] out are the NO2 and N2O concentrations outside the reactor, respectively; [NH3] in and [NH3] out is the NH3 concentration inside and outside the reactor.

[0014] The present invention uses foam copper as a substrate, and obtains amorphous Ni-WP-Se oxide by surface electrodeposition and heat treatment. The oxide should at least include copper oxide obtained by heat treatment, wherein nickel and copper can promote NO oxidation to NO2, so that Ni-WP-Se oxide can achieve a higher NO conversion rate at a lower temperature. For example, the surface acidity can be improved by modification between Ni, Mn and W, and Ni can be generated at the same time. 3+ +Cu + →Cu 2+ +Ni 2+ ; Ni 3+ +W 4+ →W 6+ +Ni 2+ ; Ni 2+ +W 4+ →W 5+ +Cu +Redox cycle. Metal oxide catalysts can produce dual redox cycles between different types of variable-valence metal oxides, and P and selenium can promote the above redox process, significantly improve electron transfer, and facilitate the adsorption / activation of NO / NH3, thereby further enhancing the redox ability of the catalyst. The active catalyst prepared by electrochemistry has high dispersibility, strong interactions between active components, and high dispersion of components to maximize the redox and acidic properties, so it has great application value. Regarding stability, it may be closely related to the fact that the in-situ deposition method makes the binding force between the active components and the foam substrate higher. At the same time, the surface morphology of the prepared amorphous Ni-WP-Se oxide is shown in the attached Figure 6 As shown, there are many pores on the surface, which give it high catalytic activity. The active surface presents a multi-rod overlapping structure with a high specific surface area. In addition, the present invention deposits amorphous Ni-WP-Se compounds by electrochemical method, which can significantly improve the thermal stability of the catalyst. Among them, pH has an important influence on the content of the active layer and should be focused on and adjusted.

[0015] Beneficial technical effects: (1) The present invention provides a method for preparing a toxic denitration catalyst, which uses foamed copper as a carrier, copper-containing Ni-WP-Se oxide as an active component, and uses electrochemical means to load the active component on the foamed copper carrier, and diffuses the copper active component to the surface of the surface active component by heat treatment, thereby significantly improving the low-temperature denitration efficiency of the catalyst. (2) The denitration catalyst of the present invention is an integral catalyst, which is simple to prepare. The electrochemical in-situ growth makes its catalytic layer not easy to fall off. For example, it has the advantages of low pressure drop, high porosity, good tensile strength and thermal shock resistance, thereby providing effective support for ensuring its excellent denitration efficiency. (3) The heat treatment of the amorphous Ni-WP-Se compound in the foamed copper of the present invention can ensure better synergy between the active substance and the carrier, which helps to further ensure its low-temperature denitration effect. Specifically, it is possible to improve the surface acidity by modifying Ni, Mn and W, and produce Ni 3+ +Cu + →Cu 2+ +Ni 2+ ; Ni 3+ +W 4+ →W 6+ +Ni 2+ ; Ni 2+ +W 4+ →W 5+ +Cu +The metal oxide catalyst can produce a dual redox cycle between different types of variable valence metal oxides, and P and selenium can promote the above redox process, significantly improve electron transfer, and facilitate the adsorption / activation of NO / NH3, thereby further enhancing the catalyst redox ability and ensuring its excellent denitration efficiency. (4) The denitration catalyst of the present invention has excellent sulfur and water resistance and maintains extremely high stability and recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Attached Figure 1 NOx conversion rate of NH3-SCR of the catalysts of the examples of the present invention and the comparative example.

[0017] Attached Figure 2 NOx selectivity of NH3-SCR of the catalysts of the examples of the present invention and the comparative examples.

[0018] Attached Figure 3 The SO2 anti-poisoning stability test of NH3-SCR of the catalysts of Example 2 of the present invention and Comparative Examples 1-2 was conducted.

[0019] Attached Figure 4 The SO2 and water anti-poisoning stability test of NH3-SCR of the catalysts of Example 2 of the present invention and Comparative Examples 1-2 was conducted.

[0020] Attached Figure 5 The SO2 and water anti-poisoning selectivity of NH3-SCR of the catalysts of Example 2 of the present invention and Comparative Examples 1-2.

[0021] Attached Figure 6 Surface morphology of amorphous Ni-WP-Se oxide prepared by the present invention. DETAILED DESCRIPTION Example 1

[0022] A method for preparing a toxic-resistant denitration catalyst. The denitration catalyst uses foamed copper as a substrate and is prepared by the following steps.

[0023] (1) Surface pretreatment of copper foam: Take copper foam of appropriate size and immerse it in acetone, ethanol and deionized water for ultrasonic cleaning in turn. The total ultrasonic cleaning time shall not exceed 40 min. Then, immerse it in 1.2 mol / L hydrochloric acid aqueous solution for 3 min. After taking it out, wash it with deionized water until it is neutral and dry it at 80 °C.

[0024] (2) Electrochemical in-situ deposition of active components: The copper foam prepared in step (1) is used as the cathode and the inert metal is used as the anode, and they are immersed in an electroplating solution, wherein the electrolyte consists of 60 g / L nickel nitrate, 40 g / L nickel tungstate, 20 g / L sodium hypophosphite, 10 g / L Na2SeO4, 110 g / L tartaric acid, 30 ml / L ammonia water and deionized water, wherein the ammonia water is a pH regulator, and the pH value of the electroplating solution is adjusted to 5.5. The electrolysis parameters are: temperature 60°C, current density 3 A / dm 2 , time is 10 minutes.

[0025] (3) Heat treatment: The copper foam treated with electrochemical in-situ deposition of active components is directly placed in a tubular furnace, heated to 60°C at 2°C / min and kept at this temperature for 24 h, then heated to 300°C at 1°C and kept at this temperature for 1 h, and then cooled naturally to obtain a toxic denitrification catalyst. Example 2

[0026] A method for preparing a toxic-resistant denitration catalyst, wherein the denitration catalyst uses foamed copper as a substrate and the catalyst is prepared by the following steps: (1) Surface pretreatment of copper foam: Take copper foam of appropriate size and immerse it in acetone, ethanol and deionized water for ultrasonic cleaning in turn. The total ultrasonic cleaning time shall not exceed 40 min. Then, immerse it in 1.275 mol / L hydrochloric acid aqueous solution for 3.5 min. After taking it out, wash it with deionized water until it is neutral and dry it at 85 °C. (2) Electrochemical in-situ deposition of active components: The copper foam prepared in step (1) is used as the cathode and the inert metal is used as the anode, and they are immersed in an electroplating solution, wherein the electrolyte is composed of 62.5 g / L nickel nitrate, 42.5 g / L nickel tungstate, 20.5 g / L sodium hypophosphite, 11.25 g / L Na2SeO4, 112.5 g / L tartaric acid, 30 ml / L ammonia water and deionized water, wherein the ammonia water is a pH regulator, and the pH value of the electroplating solution is adjusted to 5.75. The electrolysis parameters are: temperature 61.25 °C, current density 3.5 A / dm 2 , time is 11.25min; (3) Heat treatment: The copper foam treated with electrochemical in-situ deposition of active components was directly placed in a tubular furnace, heated to 62.5°C at 2°C / min and kept at this temperature for 30 h, then heated to 312.5°C at 1.25°C and kept at this temperature for 1.25 h, and then cooled naturally to obtain a toxic-resistant denitrification catalyst. Example 3

[0027] A method for preparing a toxic-resistant denitration catalyst, wherein the denitration catalyst uses foamed copper as a substrate and the catalyst is prepared by the following steps: (1) Surface pretreatment of copper foam: Take copper foam of appropriate size and immerse it in acetone, ethanol and deionized water for ultrasonic cleaning in turn. The total ultrasonic cleaning time shall not exceed 40 min. Then, immerse it in 1.35 mol / L hydrochloric acid aqueous solution for 4 min. After taking it out, wash it with deionized water until it is neutral and dry it at 90 °C. (2) Electrochemical in-situ deposition of active components: The copper foam prepared in step (1) is used as the cathode and the inert metal is used as the anode, and is immersed in an electroplating solution, wherein the electrolyte is composed of 65 g / L nickel nitrate, 45 g / L nickel tungstate, 21 g / L sodium hypophosphite, 12.5 g / L Na2SeO4, 115 g / L tartaric acid, 30 ml / L ammonia water and deionized water, wherein the ammonia water is a pH regulator, and the pH value of the electroplating solution is adjusted to 6.0. The electrolysis parameters are: temperature 62.5 °C, current density 4 A / dm 2 , time is 12.5min; (3) Heat treatment: The copper foam treated with electrochemical in-situ deposition of active components was directly placed in a tubular furnace, heated to 65°C at 2°C / min and kept at this temperature for 36 h, then heated to 325°C at 1.5°C and kept at this temperature for 1.5 h, and then cooled naturally to obtain a toxic-resistant denitrification catalyst. Example 4

[0028] A method for preparing a toxic-resistant denitration catalyst, wherein the denitration catalyst uses foamed copper as a substrate and the catalyst is prepared by the following steps: (1) Surface pretreatment of copper foam: Take copper foam of appropriate size and immerse it in acetone, ethanol and deionized water for ultrasonic cleaning in turn. The total ultrasonic cleaning time shall not exceed 40 min. Then, immerse it in 1.425 mol / L hydrochloric acid aqueous solution for 4.5 min. After taking it out, wash it with deionized water until it is neutral and dry it at 95 °C. (2) Electrochemical in-situ deposition of active components: The copper foam prepared in step (1) is used as the cathode and the inert metal is used as the anode, and they are immersed in an electroplating solution, wherein the electrolyte consists of 67.5 g / L nickel nitrate, 47.5 g / L nickel tungstate, 21.5 g / L sodium hypophosphite, 13.75 g / L Na2SeO4, 117.5 g / L tartaric acid, 30 ml / L ammonia water and deionized water, wherein the ammonia water is a pH regulator, and the pH value of the electroplating solution is adjusted to 6.25. The electrolysis parameters are: temperature 63.75 °C, current density 4.5 A / dm 2 , time is 13.75min; (3) Heat treatment: The copper foam treated with electrochemical in-situ deposition of active components was directly placed in a tubular furnace, heated to 67.5°C at 2°C / min and kept at this temperature for 42 h, then heated to 337.5°C at 1.75°C and kept at this temperature for 1.75 h, and then cooled naturally to obtain a toxic-resistant denitrification catalyst. Example 5

[0029] A method for preparing a toxic-resistant denitration catalyst. The denitration catalyst uses foamed copper as a substrate and is prepared by the following steps.

[0030] (1) Surface pretreatment of copper foam: Take copper foam of appropriate size and immerse it in acetone, ethanol and deionized water for ultrasonic cleaning in turn. The total ultrasonic cleaning time shall not exceed 40 min. Then, immerse it in 1.5 mol / L hydrochloric acid aqueous solution for 5 min. After taking it out, wash it with deionized water until it is neutral and dry it at 100 °C.

[0031] (2) Electrochemical in-situ deposition of active components: The copper foam prepared in step (1) is used as the cathode and the inert metal is used as the anode, and they are immersed in an electroplating solution, wherein the electrolyte is composed of 70 g / L nickel nitrate, 50 g / L nickel tungstate, 22 g / L sodium hypophosphite, 15 g / L Na2SeO4, 120 g / L tartaric acid, 30 ml / L ammonia water and deionized water, wherein the ammonia water is a pH regulator, and the pH value of the electroplating solution is adjusted to 6.5. The electrolysis parameters are: temperature 65°C, current density 5 A / dm 2 , time is 15 minutes.

[0032] (3) Heat treatment: The copper foam treated with electrochemical in-situ deposition of active components is directly placed in a tubular furnace, heated to 70°C at 2°C / min and kept at this temperature for 48 hours, then heated to 350°C at 2°C / min and kept at this temperature for 1-2 hours, and then cooled naturally to obtain a toxic-resistant denitrification catalyst.

[0033] Comparative Example 1 A method for preparing a toxic-resistant denitration catalyst, wherein the denitration catalyst uses foamed nickel as a substrate and the catalyst is prepared by the following steps.

[0034] (1) Surface pretreatment of nickel foam: Take a piece of copper foam of appropriate size and immerse it in acetone, ethanol and deionized water for ultrasonic cleaning in turn. The total ultrasonic cleaning time should not exceed 40 min. Then immerse it in a 1.35 mol / L hydrochloric acid aqueous solution for 4 min. After taking it out, wash it with deionized water until it is neutral and dry it at 90 °C.

[0035] (2) Electrochemical in-situ deposition of active components: The nickel foam prepared in step (1) is used as the cathode and the inert metal is used as the anode, and they are immersed in an electroplating solution, wherein the electrolyte is composed of 65 g / L nickel nitrate, 45 g / L nickel tungstate, 21 g / L sodium hypophosphite, 12.5 g / L Na2SeO4, 115 g / L tartaric acid, 30 ml / L ammonia water and deionized water, wherein the ammonia water is a pH regulator, and the pH value of the electroplating solution is adjusted to 6. The electrolysis parameters are: temperature 62.5 °C, current density 4.2 A / dm 2 , time is 12.5min.

[0036] (3) Heat treatment: The nickel foam treated with electrochemical in-situ deposition of active components was directly placed in a tubular furnace, heated to 65°C at 2°C / min and kept at this temperature for 36 h, then heated to 325°C at 1.5°C and kept at this temperature for 1.5 h, and then cooled naturally to obtain a toxic-resistant denitrification catalyst.

[0037] Comparative Example 2 A method for preparing a toxic-resistant denitration catalyst, wherein the denitration catalyst uses foamed copper as a substrate and the catalyst is prepared by the following steps.

[0038] (1) Surface pretreatment of copper foam: Take copper foam of appropriate size and immerse it in acetone, ethanol and deionized water for ultrasonic cleaning in turn. The total ultrasonic cleaning time shall not exceed 40 min. Then, immerse it in 1.35 mol / L hydrochloric acid aqueous solution for 4 min. After taking it out, wash it with deionized water until it is neutral and dry it at 90 °C.

[0039] (2) Electrochemical in-situ deposition of active components: The copper foam prepared in step (1) is used as the cathode and the inert metal is used as the anode, and they are immersed in an electroplating solution, wherein the electrolyte is composed of 65 g / L nickel nitrate, 45 g / L nickel tungstate, 21 g / L sodium hypophosphite, 12.5 g / L Na2SeO4, 115 g / L tartaric acid, 30 ml / L ammonia water and deionized water, wherein the ammonia water is a pH regulator, and the pH value of the electroplating solution is adjusted to 6. The electrolysis parameters are: temperature 62.5 °C, current density 4.2 A / dm 2 , time is 12.5min.

[0040] (3) Heat treatment: The copper foam treated with electrochemical in-situ deposition of active components is directly placed in a tubular furnace, heated by 1.5°C to 325°C and kept at this temperature for 1.5 h, and then cooled naturally to obtain a toxic denitrification catalyst.

[0041] The present invention is a denitration activity test of Examples 1-4 and Comparative Examples 1-2, as shown in the attached Figure 1 and attached Figure 2 As shown, the test conditions are: the simulated flue gas system contains 1000ppmNH3, 1000ppmNO, 3vol.% O2, 10vol.%H2O (when used), 100ppmSO2 (when used) and N2 as the balance gas. Volumetric space velocity 40000h -1 .

[0042] As the temperature increases, the NOx conversion rate of all samples gradually increases. Among them, Comparative Example 1 has almost no activity at low temperature, and only has a narrow activity window at high temperature. The NO conversion rate at around 200°C is about 90%, and the temperature window is 200-250°C. This shows the influence of the foam metal support component on the NH3-SCR activity of the catalyst. In comparison, Comparative Example 2 is replaced with foam copper, and the low-temperature catalytic activity is slightly improved, but the temperature window is significantly widened. See the attached Figure 1 , the NO conversion rate of comparative example 2 at about 200°C is about 95%, and the temperature window is 160-250°C, that is, the heat treatment has a significant effect on the diffusion of copper, especially the low-temperature sufficient oxidation process is indispensable, see Examples 1-5 for details, the active temperature window of the catalyst is significantly widened, the conversion rate at 180-220 is 100%, and the conversion in the low-temperature stage is higher than 80%, which shows that there is a synergistic effect between the copper-containing diffused Ni-WP-Se oxide metal oxides, and the selectivity is significantly improved, among which Example 2 has the best conversion rate and selectivity. In addition, the common sense of the present invention adds additional copper to the plating solution to facilitate the difference from Example 2, but the conversion rate and selectivity are not satisfactory, and there is no temperature range for 100% conversion.

[0043] For water and sulfur resistance, see Appendix Figure 3 , Attachment Figure 4 and attached Figure 5 For the sulfur resistance test alone, as time goes by, sulfur has a significant impact on the conversion rate of the catalyst, but the poisoning effect of Example 2 can be controlled within 5%. When the introduction of the sulfur source is stopped, the corresponding activity effect can be restored in a short time. In comparison, Comparative Example 2 can also be restored, while Comparative Example 1 cannot be restored at all, and the activity decreases significantly. When water and sulfur dioxide are introduced at the same time, the stability and selectivity of Example 2 can be effectively maintained, showing extremely high anti-toxicity and stability.

[0044] The above description of the exemplary embodiments should not be construed as limiting the present invention. Although a number of exemplary embodiments have been disclosed, any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, other methods for preparing metal monolithic denitration catalysts obtained by using the same or similar steps and structures as those in the above-mentioned embodiments of the present invention, as well as denitration catalysts prepared by implementing the methods, are within the scope of protection of the present invention.

Claims

1. A method for preparing a toxicity-resistant denitration catalyst, characterized in that The denitration catalyst uses foam copper as a substrate, and Ni-WP-Se oxide is in-situ attached to the surface, and the oxide morphology at least includes a rod-like structure. The catalyst is prepared by the following steps: (1) Surface pretreatment of copper foam: Take copper foam of appropriate size and immerse it in acetone, ethanol and deionized water for ultrasonic cleaning in turn. The total ultrasonic cleaning time shall not exceed 40 minutes. Then, immerse it in 1.2-1.5 mol / L hydrochloric acid aqueous solution for 3-5 minutes. After taking it out, wash it with deionized water until it is neutral, and dry it at 80-100°C. (2) Electrochemical in-situ deposition of active components: The copper foam prepared in step (1) is used as the cathode and the inert metal is used as the anode, and they are immersed in an electroplating solution, wherein the electrolyte is composed of 60-70 g / L nickel nitrate, 40-50 g / L nickel tungstate, 20-22 g / L sodium hypophosphite, 10-15 g / L Na2SeO4, 110-120 g / L tartaric acid, 30 ml / L ammonia water and deionized water, wherein the ammonia water is a pH regulator, and the pH value of the electroplating solution is adjusted to 5.5-6.

5. The electrolysis parameters are: temperature 60-65 ° C, current density 3-5 A / dm 2 , time is 10-15min; (3) Heat treatment: Place the copper foam treated with electrochemical in-situ deposition of active components directly in a tubular furnace, heat it to 60-70°C at 2°C / min and keep it at that temperature for 24-48 hours, then heat it to 300-350°C at 1-2°C and keep it at that temperature for 1-2 hours, and cool it naturally to obtain a toxic-resistant denitrification catalyst.

2. The method for preparing a toxic-resistant denitration catalyst according to claim 1, characterized in that The catalytic activity of the copper foam as a substrate is much higher than that of the nickel foam or the iron foam.

3. The method for preparing a toxic-resistant denitration catalyst according to claim 1, characterized in that Air or 10 vol.% O2 / N2 mixed gas is introduced into the tubular furnace, and the gas introduced is a non-pure inert gas or a non-reducing gas.

4. A catalyst obtained by the method for preparing a poison-resistant denitration catalyst according to any one of claims 1 to 3, characterized in that The catalyst has high low-temperature activity and high selectivity.

5. The catalyst according to claim 4, characterized in that The catalyst has extremely high resistance to SO2 and H2O poisoning.

6. Use of the catalyst as claimed in claim 4 or 5, characterized in that The catalyst is used in the field of NH3-SCR denitration.

Images