Low-temperature high-efficiency high-adaptability chromium-indium-based composite oxide denitration catalyst, preparation method and application thereof

Abstract

This invention discloses a low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst, its preparation method, and its applications, relating to the field of denitration catalyst technology. This invention utilizes manganese-modified TiO2 to enhance the oxidation capacity of the denitration catalyst while preventing the excessive oxidation of NH3 to N2O by manganese oxide crystals; it also utilizes Cr and In species to coat the surface of the manganese-modified TiO2, constructing an acid-rich environment (Cr-OH and In-OH), thereby reducing HCl adsorption capacity and improving the adaptability of the denitration catalyst. The chromium-indium-based composite oxide denitration catalyst of this invention exhibits high NO content in the temperature range of 150-325℃. x The conversion rate is higher than 80%; at the same time, the catalyst has the ability to resist HCl poisoning and can still maintain good denitrification activity at low temperatures in the presence of HCl.

Description

Technical Field

[0001] This invention relates to the field of denitrification catalyst technology, specifically to a low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitrification catalyst, its preparation method, and its application. Background Technology

[0002] Industrial boiler flue gas emissions are characterized by low flue gas temperatures and complex pollutant compositions. The flue gas temperature in industrial boilers is below 250℃, even below 200℃. Traditional commercial ammonia selective catalytic reduction (SCR) denitrification catalysts (V₂O₅-WO₃ / TiO₂) typically operate at around 350℃, which is insufficient to meet the requirements of industrial boiler flue gas under complex operating conditions. Furthermore, the pollutant composition of industrial boiler flue gas is complex, containing not only large amounts of nitrogen oxides (NOx)... x Furthermore, the presence of acidic substances such as HCl can poison and deactivate the catalyst, posing a challenge to its adaptability to complex operating conditions. These issues have become significant bottlenecks limiting the development of low-temperature, high-efficiency, and highly adaptable denitrification catalysts.

[0003] Surface oxidation regulation is an effective means to improve the low-temperature activity of denitrification catalysts. For example, adding metal oxides such as manganese, iron, and cerium can enhance oxidation capacity and promote the adsorption and activation of ammonia molecules, thereby lowering the catalyst's activation temperature. However, excessive oxidation capacity leads to the formation of N2O byproducts. Therefore, obtaining a suitable oxidation capacity is one of the design challenges of low-temperature denitrification catalysts. On the other hand, acidic substances such as HCl in flue gas easily combine with the active sites of the catalyst (such as Lewis acid sites), leading to catalyst poisoning and decreased activity. Therefore, reducing the stability of HCl adsorbate species and protecting the active sites is another challenge in the design of highly adaptable catalysts. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a low-temperature, high-efficiency, and highly adaptable chromium-indium based composite oxide denitrification catalyst, its preparation method, and its application, which can reduce NO in the temperature range of 150-325℃. x The conversion rate is higher than 80%; at the same time, the catalyst has the ability to resist HCl poisoning and can still maintain good denitrification activity at low temperatures in the presence of HCl.

[0005] The technical solution of this invention is as follows:

[0006] In a first aspect, the present invention provides a method for preparing a low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst, comprising the following steps:

[0007] S1. Tetrabutyl titanate is added to anhydrous ethanol and mixed, and stirred continuously to form solution A; manganese nitrate solution is mixed with anhydrous ethanol to form solution B; solution B is added dropwise to solution A and stirred continuously to form a gel, and then aged at room temperature.

[0008] S2 dried the aged gel and calcined it. After naturally cooling to room temperature, it was taken out to obtain manganese-modified titanium dioxide carrier powder.

[0009] S3 adds manganese-modified titanium dioxide carrier powder to water and stirs continuously to form a uniform turbid liquid. Polyvinylpyrrolidone (PVP) is added and stirred until completely dissolved. Chromium nitrate and indium nitrate are added in sequence and stirred until completely dissolved. Then hexamethylenetetramine and ethylene glycol are added and stirred continuously in a water bath heating environment until the mixed turbid liquid changes color.

[0010] S4 further evaporates and dehydrates the discolored mixed turbid liquid to obtain a gel. After drying the gel, it is calcined and taken out after natural cooling to room temperature to obtain the chromium-indium-based composite oxide denitration catalyst.

[0011] Preferably, in step S1, the concentration of manganese nitrate solution is 50-55 wt.%, the volume ratio of tetrabutyl titanate to anhydrous ethanol is (0.5-0.6):1, the volume ratio of manganese nitrate solution to anhydrous ethanol is (0.2-0.4):1, the second stirring time is 3-5 h, and the aging time is 22-24 h.

[0012] Preferably, in step S2, the gel drying temperature is 70-80℃ and the drying time is 10-12h; during calcination, the heating rate is 4.5-5.5℃ / min, the calcination temperature is 450-500℃, and the calcination time is 4-5h.

[0013] Preferably, in step S3, the content of manganese-modified titanium dioxide carrier powder in the homogeneous turbid liquid is 10-11 wt.%, the water bath heating temperature is 75-80℃, and the molar ratio of chromium and indium metal ions in polyvinylpyrrolidone, hexamethylenetetramine, ethylene glycol, chromium nitrate, and indium nitrate is (40-42):(98-102):(48-50):1; the stirring time of the final mixed turbid liquid is 5-6 h.

[0014] Preferably, in step S4, the evaporation and dehydration temperature is 75-80℃.

[0015] Preferably, in step S4, the gel drying temperature is 90-100℃, and the drying time is 10-12h; during calcination, the heating rate is 4.5-5.5℃ / min, the calcination temperature is 550-600℃, and the calcination time is 4-5h.

[0016] Preferably, in the chromium-indium based composite oxide denitration catalyst, the manganese content is 4-4.5 wt.%, the chromium content is 0.9-1 wt.%, and the indium content is 1.8-2 wt.%.

[0017] Secondly, the present invention provides a method for preparing the above-mentioned low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst, resulting in a low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst.

[0018] Thirdly, the present invention provides the application of the above-mentioned low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst, wherein the low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst removes NO. x The reaction temperature is 150-325℃.

[0019] In this invention, manganese oxide, as the main oxidizing active site, can promote the activation of adsorbed ammonia species to form -NH2 intermediate species under low-temperature conditions, reducing the reaction energy barrier of the SCR reaction and thus improving the low-temperature SCR denitrification performance of the denitrification catalyst. Simultaneously, chromium and indium species form Cr-OH and In-OH, providing abundant Brønsted acidic sites for the catalyst, which is beneficial for the adsorption of ammonia molecules and further provides an ammonia source for subsequent manganese oxidation, accelerating the reaction. On the other hand, the Brønsted acidic sites provided by chromium and indium species can provide hydrogen protons, inhibiting the deep poisoning and deactivation caused by HCl adsorption and its combination with surface metal ions to form chloride salts, thereby enhancing the denitrification catalyst's resistance to HCl poisoning.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] This invention utilizes manganese-modified TiO2 to enhance the oxidation capacity of the denitrification catalyst while preventing the excessive oxidation of NH3 by manganese oxide crystals to form N2O. Cr and In species are coated onto the surface of the manganese-modified TiO2 to create an acid-rich environment (Cr-OH and In-OH), thereby reducing HCl adsorption capacity and improving the catalyst's adaptability to denitrification. Compared to commercial V2O5-WO3 / TiO2 catalysts, the chromium-indium based composite oxide denitrification catalyst prepared in this invention can achieve NO reduction even at a low temperature of 150℃. x Highly efficient catalytic reduction to form N2 and H2O, within a temperature range of 150-325℃, NO x The conversion rate is higher than 80%; at the same time, the catalyst has the ability to resist HCl poisoning. After HCl poisoning treatment, the catalyst can withstand NO at 175℃. x The conversion rate is higher than 90%, meaning that it maintains good denitrification activity at low temperatures even in the presence of HCl. This denitrification catalyst can be applied to NO removal in complex emission scenarios involving acidic gases from industrial boilers. x Selective catalytic reduction, with catalytic activity meeting emission requirements. Attached Figure Description

[0022] Figure 1 This is a graph showing the change in the activity of the denitrification catalysts in Examples 1-3 of the present invention with aging time.

[0023] Figure 2 These are the test graphs for evaluating the activity of the denitrification catalysts in Example 1 and Comparative Examples 1-5 of the present invention.

[0024] Figure 3 These are the test graphs for evaluating the activity of the denitrification catalysts in Example 1 and Comparative Examples 6-8 of this invention.

[0025] Figure 4 This is a test diagram evaluating the adaptability of the denitrification catalyst against HCl poisoning in Experimental Examples 1-2 of this invention. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0027] Example 1

[0028] The preparation method of the low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst (CrIn / Mn-TiO2) in this embodiment includes the following steps:

[0029] S1 Add tetrabutyl titanate to anhydrous ethanol at a volume ratio of 0.5:1 and mix with continuous stirring to form solution A; mix manganese nitrate solution (50 wt.%) with anhydrous ethanol at a volume ratio of 0.2:1 to form solution B; add solution B dropwise to solution A and stir continuously for 3 hours to form a gel; age the gel at room temperature for 23 hours.

[0030] S2 transferred the aged gel to a 70℃ drying oven and dried it for 12 hours. Then it was transferred to a muffle furnace for calcination. The heating rate was set to 5℃ / min. The gel was calcined at 500℃ for 4 hours. After naturally cooling to room temperature, it was taken out to obtain manganese-modified titanium dioxide carrier powder.

[0031] S3. Manganese-modified titanium dioxide carrier powder was added to deionized water and stirred continuously to form a homogeneous turbid liquid, wherein the content of manganese-modified titanium dioxide carrier powder was 10 wt.%. Polyvinylpyrrolidone, hexamethylenetetramine, ethylene glycol and metal ions were added to the homogeneous turbid liquid according to a molar ratio of 40:100:50:1, and stirred until completely dissolved. Then chromium nitrate and indium nitrate were added and stirred until completely dissolved. Finally, hexamethylenetetramine and ethylene glycol were added, and the mixture was stirred continuously in an 80°C water bath for 5 hours until the mixed turbid liquid changed color.

[0032] S4 further evaporated and dehydrated the discolored mixed turbid liquid in an 80℃ water bath to obtain a gel. The gel was dried in air at 100℃ for 12 hours, and then transferred to a muffle furnace and calcined at 600℃ for 4 hours at a heating rate of 5℃ / min. After naturally cooling to room temperature, it was removed to obtain the CrIn / Mn-TiO2 denitration catalyst. The denitration catalyst contained 4 wt.% manganese, 1 wt.% chromium, and 2 wt.% indium.

[0033] Example 2

[0034] The preparation method of the low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst (CrIn / Mn-TiO2) in this embodiment includes the following steps:

[0035] S1 Add tetrabutyl titanate to anhydrous ethanol at a volume ratio of 0.5:1 and mix with continuous stirring to form solution A; mix manganese nitrate solution (54 wt.%) with anhydrous ethanol at a volume ratio of 0.3:1 to form solution B; add solution B dropwise to solution A and stir continuously for 4 hours to form a gel; age the gel at room temperature for 22 hours.

[0036] S2 transferred the aged gel to a 75℃ drying oven and dried it for 11 hours. Then it was transferred to a muffle furnace for calcination. The heating rate was set to 5.5℃ / min. The calcination was carried out at 450℃ for 5 hours. After naturally cooling to room temperature, it was taken out to obtain manganese-modified titanium dioxide carrier powder.

[0037] S3. Manganese-modified titanium dioxide carrier powder was added to deionized water and stirred continuously to form a homogeneous turbid liquid, wherein the content of manganese-modified titanium dioxide carrier powder was 10.5 wt.%. Polyvinylpyrrolidone, hexamethylenetetramine, ethylene glycol, and metal ions were added to the homogeneous turbid liquid according to a molar ratio of 41:98:48:1, and stirred until completely dissolved. Then chromium nitrate and indium nitrate were added and stirred until completely dissolved. Finally, hexamethylenetetramine and ethylene glycol were added, and the mixture was stirred continuously in a 78°C water bath for 5.5 hours until the mixed turbid liquid changed color.

[0038] S4 further evaporated and dehydrated the discolored mixed turbid liquid in a 78℃ water bath to obtain a gel. The gel was dried in air at 95℃ for 11 hours, and then transferred to a muffle furnace and calcined at 580℃ for 4.5 hours at a heating rate of 4.5℃ / min. After naturally cooling to room temperature, it was removed to obtain the CrIn / Mn-TiO2 denitration catalyst. The obtained denitration catalyst contained 4.2 wt.% manganese, 0.95 wt.% chromium, and 1.9 wt.% indium.

[0039] Example 3

[0040] The preparation method of the low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst (CrIn / Mn-TiO2) in this embodiment includes the following steps:

[0041] S1 Add tetrabutyl titanate to anhydrous ethanol at a volume ratio of 0.6:1 and mix with continuous stirring to form solution A; mix manganese nitrate solution (55 wt.%) with anhydrous ethanol at a volume ratio of 0.4:1 to form solution B; add solution B dropwise to solution A and stir continuously for 5 hours to form a gel; age the gel at room temperature for 24 hours.

[0042] S2 transferred the aged gel to an 80℃ drying oven for 10 hours, then transferred it to a muffle furnace for calcination at a heating rate of 4.5℃ / min for 4.5 hours at 480℃. After natural cooling to room temperature, the gel was removed to obtain manganese-modified titanium dioxide carrier powder.

[0043] S3 adds manganese-modified titanium dioxide carrier powder to deionized water and stirs continuously to form a homogeneous turbid liquid, wherein the content of manganese-modified titanium dioxide carrier powder is 11 wt.%; according to the molar ratio of polyvinylpyrrolidone, hexamethylenetetramine, ethylene glycol, and metal ions of 42:102:50:1, polyvinylpyrrolidone is added to the homogeneous turbid liquid and stirred until completely dissolved. Then chromium nitrate and indium nitrate are added and stirred until completely dissolved. Finally, hexamethylenetetramine and ethylene glycol are added, and the mixture is stirred continuously in a 75°C water bath for 6 hours until the mixed turbid liquid changes color.

[0044] S4 further evaporated and dehydrated the discolored mixed turbid liquid in a 75℃ water bath to obtain a gel. The gel was dried in air at 90℃ for 10 hours, and then transferred to a muffle furnace and calcined at 550℃ for 5 hours at a heating rate of 5.5℃ / min. After naturally cooling to room temperature, it was removed to obtain the CrIn / Mn-TiO2 denitration catalyst. The denitration catalyst contained 4.5 wt.% manganese, 0.95 wt.% chromium, and 1.8 wt.% in manganese.

[0045] Comparative Example 1

[0046] Comparative Example 1 prepared a manganese-modified titanium dioxide denitration catalyst (Mn-TiO2). The difference between its preparation method and that of Example 1 is that steps S3 and S4 are not performed. The final Mn-TiO2 denitration catalyst has a manganese content of 4 wt.%.

[0047] Comparative Example 2

[0048] Comparative Example 2 prepared an unmodified chromium-indium composite oxide denitration catalyst (CrIn / TiO2). The difference between its preparation method and that of Example 1 is that anatase titanium dioxide powder was used instead of the manganese-modified titanium dioxide support powder prepared in step S2 of Example 1. In the final CrIn / TiO2 denitration catalyst, the chromium content was 1 wt.% and the indium content was 2 wt.%.

[0049] Comparative Example 3

[0050] Comparative Example 3 prepared a manganese-modified chromium-based composite oxide denitration catalyst (Cr / Mn-TiO2). The difference between its preparation method and that of Example 1 is that in step S3, indium nitrate is not added. In the final Cr / Mn-TiO2 denitration catalyst, the manganese content is 4 wt.% and the chromium content is 1 wt.%.

[0051] Comparative Example 4

[0052] Comparative Example 4 prepared a manganese-modified indium-based composite oxide denitration catalyst (In / Mn-TiO2). The difference between its preparation method and that of Example 1 is that chromium nitrate was not added in step S3. The final In / Mn-TiO2 denitration catalyst contained 4 wt.% manganese and 2 wt.% indium.

[0053] Comparative Example 5

[0054] Comparative Example 5 describes the preparation of a conventional commercial vanadium-tungsten-titanium denitration catalyst (V2O5-WO3 / TiO2), which includes the following steps:

[0055] S1. Ammonium metavanadate and oxalic acid are added to deionized water at a molar ratio of 1:3. The mixture is ultrasonically stirred for 20 minutes to form a mixed solution. Ammonium metatungstate (molar ratio of ammonium metavanadate to ammonium metatungstate is 1:5) is added to the mixed solution and stirred continuously for 30 minutes until fully dissolved to form solution A.

[0056] S2 mixes solution A with anatase titanium dioxide powder and stirs for 1 hour, then stirs until dry under 80°C water bath conditions, and then transfers it to a 110°C drying oven in a fume hood to dry for 12 hours.

[0057] S3 grinds the dried solid into powder and puts it into a muffle furnace, heats it at a heating rate of 10℃ / min, and calcines it at 600℃ for 5h; the resulting V2O5-WO3 / TiO2 denitration catalyst contains 1wt.% vanadium and 5wt.% tungsten.

[0058] Comparative Example 6

[0059] Comparative Example 6 prepared a cobalt-nickel-based composite oxide denitration catalyst (CoNi / Mn-TiO2). The difference between its preparation method and that of Example 1 is that cobalt nitrate and nickel nitrate were used instead of chromium nitrate and indium nitrate in step S3 of Example 1. The final CoNi / Mn-TiO2 denitration catalyst contained 4 wt.% manganese, 1 wt.% cobalt, and 2 wt.% nickel.

[0060] Comparative Example 7

[0061] Comparative Example 7 prepared a chromium-cobalt based composite oxide denitration catalyst (CrCo / Mn-TiO2). The difference between its preparation method and that of Example 1 is that cobalt nitrate was used instead of indium nitrate in step S3 of Example 1. The final CrCo / Mn-TiO2 denitration catalyst contained 4 wt.% manganese, 1 wt.% Cr, and 2 wt.% Co.

[0062] Comparative Example 8

[0063] Comparative Example 8 prepared a nickel-indium-based composite oxide denitration catalyst (NiIn / Mn-TiO2). The difference between its preparation method and that of Example 1 is that nickel nitrate was used instead of chromium nitrate in step S3 of Example 1. The final NiIn / Mn-TiO2 denitration catalyst contained 4 wt.% manganese, 1 wt.% Ni, and 2 wt.% In.

[0064] Experimental Example 1

[0065] This experimental example prepares an HCl-treated chromium-indium-based composite oxide denitration catalyst (CrIn / Mn-TiO2(Cl)), and the preparation method includes the following steps:

[0066] S1. 200 mg of the CrIn / Mn-TiO2 denitration catalyst prepared in Example 1 was treated for 4 h in an atmosphere with 100 ppm HCl and N2 as the equilibrium gas and a total flow rate of 200 mL / min at a treatment temperature of 200 °C.

[0067] S2 purged the HCl-treated CrIn / Mn-TiO2 denitration catalyst with nitrogen for 30 min at room temperature to obtain the CrIn / Mn-TiO2(Cl) denitration catalyst.

[0068] Experiment Example 2

[0069] This experimental example prepares an HCl-treated manganese-modified titanium dioxide denitration catalyst (Mn-TiO2(Cl)), and the preparation method includes the following steps:

[0070] S1 The Mn-TiO2 denitration catalyst prepared in Comparative Example 1 was treated for 4 h in an atmosphere of 100 ppm HCl, N2 as the equilibrium gas, and a total flow rate of 200 mL / min at a temperature of 200 °C.

[0071] S2 purged the HCl-treated Mn-TiO2 denitration catalyst with nitrogen for 30 min at room temperature to obtain the Mn-TiO2(Cl) denitration catalyst.

[0072] The denitrification catalysts prepared in Examples 1-3, Comparative Examples 1-8, and Experimental Examples 1-2 were subjected to activity evaluation tests under the following conditions: 500 ppm NO. x (450ppm NO, 50ppm NO2), 500ppm NH3, 4% O2, N2 as balance gas, total flow rate 200mL / min, gas hourly space velocity (GHSV) 40000mL·g -1 ·h -1 .

[0073] like Figure 1 As shown, the denitrification activity of the denitrification catalysts in Examples 1-3 improved with increasing aging time. However, the improvement was not significant after aging for more than 23 hours, because the particles had formed a mature network structure through Ostwald maturation and accumulation. Figure 2 As shown, Example 1 exhibits higher low-temperature denitrification activity compared to the denitrification catalysts of Comparative Examples 2-5. This is attributed to the formation of Cr-OH and In-OH acid centers by chromium and indium species, which synergistically work with manganese oxide oxidation centers to promote efficient acid and redox cycles, thereby lowering the reaction energy barrier of the SCR reaction. Figure 3 As shown, compared with Comparative Examples 6-8, the temperature (T) corresponding to a conversion rate of 50% in Example 1 is... 50 ) and the temperature (T) corresponding to a conversion rate of 90%. 90 The significant decrease in [acidity] indicates a better synergistic effect between chromium and indium; while the denitration catalysts in comparative examples 6-8, due to the replacement of chromium and indium, resulted in the partial destruction of the diacid centers, which is detrimental to the SCR reaction. Figure 4 As shown, the evaluation results of the HCl poisoning resistance of Experiments 1-2 indicate that the denitrification catalyst prepared in Example 1 exhibits stronger resistance to HCl poisoning and can still achieve a denitrification efficiency of over 95% at 175℃. This is because the Brønsted acidic sites provided by chromium and indium species can offer hydrogen protons, inhibiting the deep poisoning and deactivation caused by HCl adsorption and its combination with surface metal ions to form chloride salts, thereby enhancing the denitrification catalyst's resistance to HCl poisoning.

Claims

1. A method for preparing a low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst, characterized in that, Includes the following steps: S1 Add tetrabutyl titanate to anhydrous ethanol and mix, stirring continuously to form solution A; Manganese nitrate solution was mixed with anhydrous ethanol to form solution B; solution B was added dropwise to solution A, and the mixture was stirred continuously to form a gel, which was then aged at room temperature. S2 dried the aged gel and calcined it. After naturally cooling to room temperature, it was taken out to obtain manganese-modified titanium dioxide carrier powder. S3 adds manganese-modified titanium dioxide carrier powder to water and stirs continuously to form a uniform turbid liquid. Polyvinylpyrrolidone is added and stirred until completely dissolved. Chromium nitrate and indium nitrate are added in sequence and stirred until completely dissolved. Then hexamethylenetetramine and ethylene glycol are added and stirred continuously in a water bath heating environment until the mixed turbid liquid changes color. S4 further evaporates and dehydrates the discolored mixed turbid liquid to obtain a gel. After drying the gel, it is calcined and taken out after natural cooling to room temperature to obtain the chromium-indium-based composite oxide denitration catalyst.

2. The preparation method of the low-temperature, high-efficiency, and highly adaptable chromium-indium based composite oxide denitration catalyst as described in claim 1, characterized in that, In step S1, the concentration of manganese nitrate solution is 50-55 wt.%, the volume ratio of tetrabutyl titanate to anhydrous ethanol is (0.5-0.6):1, the volume ratio of manganese nitrate solution to anhydrous ethanol is (0.2-0.4):1, the second stirring time is 3-5 h, and the aging time is 22-24 h.

3. The preparation method of the low-temperature, high-efficiency, and highly adaptable chromium-indium based composite oxide denitration catalyst as described in claim 1, characterized in that, In step S2, the gel drying temperature is 70-80℃ and the drying time is 10-12h; during calcination, the heating rate is 4.5-5.5℃ / min, the calcination temperature is 450-500℃, and the calcination time is 4-5h.

4. The preparation method of the low-temperature, high-efficiency, and highly adaptable chromium-indium based composite oxide denitration catalyst as described in claim 1, characterized in that, In step S3, the content of manganese-modified titanium dioxide carrier powder in the homogeneous turbid liquid is 10-11 wt.%, the water bath heating temperature is 75-80℃, and the molar ratio of chromium and indium metal ions in polyvinylpyrrolidone, hexamethylenetetramine, ethylene glycol, chromium nitrate, and indium nitrate is (40-42):(98-102):(48-50):1; the stirring time of the final mixed turbid liquid is 5-6 h.

5. The preparation method of the low-temperature, high-efficiency, and highly adaptable chromium-indium based composite oxide denitration catalyst as described in claim 1, characterized in that, In step S4, the evaporation and dehydration temperature is 75-80℃.

6. The preparation method of the low-temperature, high-efficiency, and highly adaptable chromium-indium based composite oxide denitration catalyst as described in claim 1, characterized in that, In step S4, the gel drying temperature is 90-100℃ and the drying time is 10-12h; during calcination, the heating rate is 4.5-5.5℃ / min, the calcination temperature is 550-600℃, and the calcination time is 4-5h.

7. The preparation method of the low-temperature, high-efficiency, and highly adaptable chromium-indium based composite oxide denitration catalyst as described in claim 1, characterized in that, The chromium-indium based composite oxide denitration catalyst contains 4-4.5 wt.% manganese, 0.9-1 wt.% chromium, and 1.8-2 wt.% indium.

8. The low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitration catalyst prepared by the preparation method of any one of claims 1-7.

9. The application of the low-temperature, high-efficiency, and highly adaptable chromium-indium based composite oxide denitration catalyst as described in claim 8, characterized in that, The low-temperature, high-efficiency, and highly adaptable chromium-indium-based composite oxide denitrification catalyst removes NO. x The reaction temperature is 150-325℃.

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