CuOx / CeO2 catalyst with ammonium complexed with Cu < 2 + > as well as preparation method and application of CuOx / CeO2 catalyst

Abstract

The invention discloses an ammonium complexation Cu < 2 + > CuOx / CeO2 catalyst as well as a preparation method and application thereof, and belongs to the technical field of functional environment materials. The preparation method comprises the following steps: mixing a CeO2 suspension and a Cu (NO3) 2.3 H2O aqueous solution, complexing and precipitating Cu < 2 + > by using a (NH4) 2CO3 aqueous solution to regulate the state of a key copper species, filtering, drying and calcining to prepare the NH4-CuOx / CeO2 catalyst. The NH4-CuOx / CeO2 catalyst is synthesized by utilizing a simple complex-precipitation deposition method, high-concentration pollutant CO can be quickly oxidized under the conditions of no noble metal and mild illumination, the catalyst is used for a technology for removing high-concentration carbon monoxide at a low temperature, and the catalyst is wide in raw material source, free of noble metal, simple in preparation method, capable of realizing large-scale industrial mass production and suitable for industrial production. The reaction conditions are mild and pollution-free, and the method has good economic benefits and application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional environmental materials, and specifically relates to an ammonium complex Cu 2+ CuO x / CeO 2 Catalyst and its preparation method and application. Background Art

[0002] Carbon monoxide (CO) is a common air pollutant that is seriously harmful to human health. Its sources are mainly industrial production, chemical synthesis, motor vehicle exhaust, incomplete combustion of fuel, etc. In relatively closed spaces such as underground parking lots, residential homes, and ship cabins, CO is easily produced but difficult to dissipate, causing high-concentration, sudden pollution. Catalytic oxidation is a relatively effective method for removing CO in closed spaces. CeO 2 Since the 4f and 5d orbital energy levels are similar and it is easy to gain or lose electrons, it is widely used as a carrier of supported catalysts. Considering the limited reserves and high prices of precious metals, non-precious metal Cu has attracted people's attention in recent years. x / CeO 2 The excellent CO oxidation activity of the catalysts has also been widely reported.

[0003] Alkali metals are often used as promoters in the oxidation of noble metal CO. In the early experimental work, alkali metal Na + The CuO with excellent photocatalytic activity was obtained by modification x / CeO 2 The catalyst was found to be mainly low-valent Cu species and active oxygen species that played a positive role. Based on this, the state of copper species was regulated by ammonium complexation, hoping to further improve the catalyst's ability to remove high-concentration CO by oxidation.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] In view of the above problems existing in the prior art, the first technical problem to be solved by the present invention is to provide an ammonium complex Cu 2+ CuO x / CeO 2 The preparation method of the catalyst is simple, has mild reaction conditions, does not contain precious metals, and is pollution-free. NH 4 -CuO x / CeO 2 Catalytic material. The second technical problem to be solved by the present invention is to provide an ammonium complex Cu 2+ CuO x / CeO 2The catalyst has excellent light capture performance and CO oxidation ability. The third technical problem to be solved by the present invention is to provide an ammonium complex Cu 2+ CuO x / CeO 2 The application of the catalyst, which can quickly oxidize the pollutant CO under mild conditions without precious metals, is used to remove high-concentration CO.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] An ammonium complexed Cu 2+ CuO x / CeO 2 The preparation method of the catalyst is to 2 Suspension, Cu(NO 3 ) 2 ·3H 2 O aqueous solution and (NH 4 ) 2 CO 3 The aqueous solution is mixed, the resulting mixture is aged, centrifuged, filtered, dried, ground, calcined, and then cooled to room temperature to obtain NH 4 -CuO x / CeO 2 catalyst.

[0008] Furthermore, the pH of the mixed solution is 9.

[0009] Furthermore, the aging time is 1 hour.

[0010] Furthermore, the calcination temperature is increased to 400° C. at a rate of 5° C. / min, and the calcination time is 4 hours.

[0011] Furthermore, the ammonium complexed Cu 2+ CuO x / CeO 2 The preparation method of the catalyst comprises the following steps:

[0012] 1) Weigh Ce(NO 3 ) 3 6H 2 O was dissolved in deionized water, stirred rapidly on a magnetic stirrer, and then NH 3 ·H 2 O until the pH is 10, then aged for 12 hours, centrifuged and filtered, washed with deionized water three times, dried in an oven, ground into powder, placed in a crucible, placed in a muffle furnace and heated to 550°C at 5°C / min for 2 hours, cooled to room temperature, and obtained CeO 2 Carrier;

[0013] 2) The CeO prepared in step 1) 2 The carrier was added into deionized water and stirred rapidly on a magnetic stirrer to obtain CeO 2 Suspension; weigh Cu(NO 3 ) 2 ·3H 2 O in deionized water, add CeO dropwise 2 The suspension was then added dropwise with (NH 4 ) 2 CO 3 The aqueous solution was heated to pH 9 for 1 h, centrifuged and filtered, dried at 75 °C for 12 h, ground into powder, and then placed in a muffle furnace and heated to 400 °C at 5 °C / min for 4 h, and cooled to room temperature to obtain NH 4 -CuO x / CeO 2 catalyst.

[0014] Further, the NH 4 -CuO x / CeO 2 catalyst.

[0015] Furthermore, CuO x and CeO 2 The mass ratio is 1:100.

[0016] Furthermore, the NH 4 -CuO x / CeO 2 Application of catalysts in removing high concentration CO.

[0017] Furthermore, the application comprises the following steps:

[0018] 1) Weigh 200 mg NH 4 -CuO x / CeO 2 The catalyst is in a reaction tube of a fixed bed reactor;

[0019] 2) A 300W xenon lamp was added to illuminate the catalyst in the reaction tube with full spectrum light, and then 4% CO+He and 4% O were introduced at a total air flow rate of 50 mL / min. 2 +He and 99.999% high-purity He are three kinds of raw materials. After catalysis, the tail gas is separated by chromatography and quantified by the equipped FID detector.

[0020] Furthermore, in step 2), the concentration of CO is 10000 ppm; the catalytic time is 40 min; the tail gas is chromatographically separated and quantitatively detected by the equipped FID detector, and the conversion rate of CO reaches 90%.

[0021] Compared with the prior art, the advantages of the present invention are:

[0022] (1) The present invention utilizes a simple ammonium complex precipitation method to synthesize NH 4 -CuO x / CeO 2 Catalyst, compared to K + Or Na + Modified K-CuO x / CeO 2 and Na-CuO x / CeO 2 Catalyst, NH prepared by the present invention 4 -CuO x / CeO 2 The catalyst has a wide range of sources, low raw material costs, simple preparation methods, mild and pollution-free reaction conditions, and most importantly, can produce more key active copper species, with good economic benefits and application prospects.

[0023] (2) NH prepared by the present invention 4 -CuO x / CeO 2 The catalyst can quickly oxidize the pollutant CO under mild light conditions without precious metals. It can quickly generate oxygen-containing free radicals under mild light conditions, promoting the oxidation of more CO molecules. Compared with K-CuO x / CeO 2 Catalyst and Na-CuO x / CeO 2 Catalyst, NH 4 -CuO x / CeO 2 The ability to catalytically purify high-concentration pollutants has been significantly improved.

[0024] (3) NH prepared by the present invention 4 -CuO x / CeO 2 The catalyst has excellent environmental stability and has potential application prospects in the rapid elimination of high-concentration CO in confined spaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 XRD spectrum of the sample prepared by the present invention;

[0026] Figure 2 This is the XPS O 1s spectrum of the sample prepared in the present invention;

[0027] Figure 3 Raman spectrum of the sample prepared by the present invention;

[0028] Figure 4 This is the XPS Cu 2p spectrum of the sample prepared by the present invention;

[0029] Figure 5 This is the EIS spectrum of the sample prepared by the present invention;

[0030] Figure 6 PL spectrum of the sample prepared by the present invention;

[0031] Figure 7 This is a comparison chart of the CO oxidation performance of the samples prepared in the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with specific embodiments.

[0033] The chemical reagents used in the following examples were obtained from commercial sources. 3 ) 3 6H 2 O (Aladdin, Nanjing Wanqing Chemical Glass Instrument Co., Ltd.), NH 3 ·H 2 O (Sino-pharmaceutical-Shanghai trial, Nanjing Wanqing Chemical Glass Instrument Co., Ltd.), Cu(NO 3 ) 2 ·3H 2 O(Aladdin, Nanjing Zebra Experimental Equipment Co., Ltd.), (NH 4 ) 2 CO 3 (Aladdin, Nanjing Wanqing Chemical Glass Instrument Co., Ltd.), K 2 CO 3 (Aladdin, Nanjing Wanqing Chemical Glass Instrument Co., Ltd.), Na 2 CO 3 (Adamas, Nanjing Jingge Chemical Technology Co., Ltd.).

[0034] Example 1

[0035] 1. CeO 2 Preparation of vector

[0036] Weigh about 10 g of Ce(NO 3 ) 3 6H 2 O was dissolved in 200 mL of deionized water and stirred rapidly on a magnetic stirrer; NH 3 ·H 2O until the pH reaches 10; after aging the obtained mixture for 12 hours, centrifuge and filter at a centrifugal force of 10000r / min and wash with deionized water for 3 times; put the washed sample into an oven and dry it at 100℃ for 24 hours; grind the dried sample into fine powder with a mortar; put the powder into a crucible, increase the temperature to 550℃ in a muffle furnace at 5℃ / min, calcine for 2 hours, cool to room temperature, take out, collect and store, and obtain CeO 2 carrier.

[0037] 2. NH 4 -CuO x / CeO 2 Catalyst preparation

[0038] Weigh 2g CeO 2 The powder was placed in 100 mL of deionized water and stirred rapidly on a magnetic stirrer to obtain CeO 2 Suspension; weigh 0.0608g Cu(NO 3 ) 2 ·3H 2 O solid was dissolved in 50 mL of deionized water and added dropwise to the above CeO 2 In the suspension; weigh 2.4g (NH 4 ) 2 CO 3 The solid was dissolved in 50 mL of deionized water and added dropwise to the above CeO 2 The suspension was stirred until pH = 9; stirring was stopped and the suspension was aged at room temperature for 1 hour; the sample after centrifugal filtration was placed in an oven and dried at 75°C for 12 hours; the dried sample was ground into fine powder using a mortar; the powder was placed in a crucible and calcined in a muffle furnace at 5°C / min to 400°C for 4 hours, and then taken out and collected after cooling to room temperature to obtain ammonium complexed Cu 2+ CuO x / CeO 2 Catalyst, denoted as NH 4 -CuO x / CeO 2 .

[0039] 3. K-CuO x / CeO 2 Catalyst preparation

[0040] Weigh 2g CeO 2 The powder was placed in 100 mL of deionized water and stirred rapidly on a magnetic stirrer; 0.0608 g Cu(NO 3 ) 2 ·3H 2 O solid was dissolved in 50 mL of deionized water and added dropwise to the CeO 2In the suspension; weigh 3.46g K 2 CO 3 The solid was dissolved in 50 mL of deionized water and added dropwise to the above CeO 2 The suspension was stirred until pH = 9; stirring was stopped and the suspension was aged at room temperature for 1 hour; the sample after centrifugal filtration was placed in an oven and dried at 75°C for 12 hours; the dried sample was ground into fine powder using a mortar; the powder was placed in a crucible and calcined in a muffle furnace at 5°C / min to 400°C for 4 hours, and then taken out and stored after cooling to room temperature to obtain K + Modified CuO x / CeO 2 Catalyst, denoted as K-CuO x / CeO 2 .

[0041] 4. Na-CuO x / CeO 2 Catalyst preparation

[0042] Weigh 2g CeO 2 The powder was placed in 100 mL of deionized water and stirred rapidly on a magnetic stirrer; 0.0608 g Cu(NO 3 ) 2 ·3H 2 O solid was dissolved in 50 mL of deionized water and added dropwise to the CeO 2 In the suspension; weigh 2.65g Na 2 CO 3 The solid was dissolved in 50 mL of deionized water and added dropwise to the above CeO 2 The suspension was stirred until pH = 9; stirring was stopped and the suspension was aged at room temperature for 1 hour; the sample after centrifugal filtration was placed in an oven and dried at 75°C for 12 hours; the dried sample was ground into fine powder using a mortar; the powder was placed in a crucible and calcined in a muffle furnace at 5°C / min to 400°C for 4 hours, and then taken out and collected after cooling to room temperature to obtain Na + Modified CuO x / CeO 2 Catalyst, denoted as Na-CuO x / CeO 2 .

[0043] Figure 1 The XRD spectrum of the sample prepared in the present invention is shown in FIG. 4 -CuO x / CeO 2 、K-CuO x / CeO 2 and Na-CuO x / CeO 2From the XRD diffraction peaks, we can see that only the peaks attributable to CeO 2 The diffraction peaks of CeO 2 Cubic fluorite structure.

[0044] Figure 2 This is the XPS O 1s spectrum of the sample prepared in the present invention. 4 -CuO x / CeO 2 、K-CuO x / CeO 2 and Na-CuO x / CeO 2 The XPS O 1s spectrum shows that NH 4 -CuO x / CeO 2 It has the most surface-adsorbed active oxygen species, which helps to produce more strongly oxidizing oxygen-containing free radicals under light and promotes the oxidation of CO.

[0045] Figure 3 This is the Raman spectrum of the sample prepared by the present invention. 4 -CuO x / CeO 2 、K-CuO x / CeO 2 and Na-CuO x / CeO 2 From the Raman diagram, we can see that NH 4 -CuO x / CeO 2 Corresponding (I D +I 2LO ) / I F2g The highest value indicates that during the calcination process, NH 4 + Detachment induces more CeO 2 The removal of lattice oxygen generates abundant oxygen vacancies, which are beneficial to the adsorption and activation of surface adsorbed oxygen species, and are reduced by photogenerated electrons into highly oxidizing superoxide radicals, promoting the oxidation of CO.

[0046] Figure 4 XPS Cu 2p spectrum of the sample prepared in the present invention; 4 -CuO x / CeO 2 、K-CuO x / CeO 2 and Na-CuO x / CeO 2 The XPS Cu 2p map shows that NH 4 -CuOx / CeO 2 Cu 2p 3 / 2 The peak deviates to the low binding energy, indicating that ammonium complexation stabilizes copper species during the preparation process, producing more low-valent Cu (such as Cu + ), which is beneficial to the adsorption and activation of pollutant CO molecules.

[0047] Figure 5 , 6 The EIS and PL spectra of the samples prepared by the present invention are respectively; 4 -CuO x / CeO 2 、K-CuO x / CeO 2 and Na-CuO x / CeO 2 From the EIS and PL spectra, we can see that NH 4 -CuO x / CeO 2 It has the best photogenerated carrier separation efficiency and improves the utilization rate of light energy.

[0048] Example 2

[0049] Example 1 NH 4 -CuO x / CeO 2 、K-CuO x / CeO 2 、Na-CuO x / CeO 2 Test of photocatalytic oxidation of CO:

[0050] The photocatalytic CO oxidation reaction test was carried out using a fixed bed reaction device. The photocatalytic CO oxidation activity was tested by applying full-spectrum illumination to the catalyst part of the reaction tube with an external xenon lamp light source with a total power of 300W. The tail gas was quantified by the equipped FID detector after chromatographic separation. Three raw gas: mixed gas 4% CO + He, mixed gas 4% O 2 +He, high purity He (99.999%), total inlet flow rate of 50mL / min, CO concentration of 10000ppm, 200mg catalyst. CO conversion rate is calculated by the following formula:

[0051]

[0052] Figure 7 The photocatalytic CO oxidation performance comparison diagram of the samples prepared in the present invention is shown in Figure 1. 4 -CuO x / CeO 2 、K-CuO x / CeO 2 and Na-CuO x / CeO 2 The catalytic performance comparison chart shows that NH 4 -CuO x / CeO 2 It has good photocatalytic activity, and the CO removal rate reaches more than 90% after 40 minutes of illumination. x / CeO 2 and Na-CuO x / CeO 2 The photocatalytic activity of ammonium complexed Cu 2+ NH 4 -CuO x / CeO 2 The catalyst can achieve rapid conversion of high-concentration CO pollutants under mild light conditions, and its photocatalytic performance in purifying pollutants is significantly improved compared to other cationic precipitants. This is mainly due to the complexation of ammonium and copper, which stabilizes and optimizes the existence state of copper species. + The production of NH 4 + Decomposition-induced CeO 2 The removal of lattice oxygen produces more oxygen vacancies, which is beneficial to the adsorption of active oxygen species, which form strong oxidizing free radicals under light. The above two effects synergistically realize the ammonium complexation of Cu 2+ NH 4 -CuO x / CeO 2 The catalyst rapidly oxidizes and removes high concentrations of CO pollutants.

Claims

1. An ammonium complexed Cu 2+ CuO x / CeO2 catalyst preparation method, characterized in that, CeO2 suspension, Cu(NO3)2·3H2O aqueous solution and (NH4)2CO3 aqueous solution are mixed, the obtained mixed solution is aged, centrifuged, filtered, dried, ground, calcined, and then cooled to room temperature to obtain NH4-CuO x / CeO2 catalyst.

2. Ammonium complexed Cu according to claim 1 2+ CuO x / CeO2 catalyst preparation method, characterized in that, The pH of the mixed solution is 9.

3. Ammonium complexed Cu according to claim 1 2+ CuO x / CeO2 catalyst preparation method, characterized in that, The aging time is 1 h.

4. Ammonium complexed Cu according to claim 1 2+ CuO x / CeO2 catalyst preparation method, characterized in that, The calcination temperature was raised to 400° C. at a rate of 5° C. / min, and the calcination time was 4 h.

5. Ammonium complexed Cu according to claim 1 2+ CuO x / CeO2 catalyst preparation method, characterized in that, Here are the steps: 1) Weigh Ce(NO3)3·6H2O and dissolve it in deionized water, stir it quickly on a magnetic stirrer, then add NH3·H2O dropwise until the pH is 10, then age it for 12 hours, centrifuge it and wash it with deionized water for 3 times, put it in an oven to dry, grind it into powder, put the powder in a crucible and place it in a muffle furnace, heat it to 550°C at 5°C / min and calcine it for 2 hours, and then cool it to room temperature to obtain a CeO2 carrier; 2) adding the CeO2 carrier prepared in step 1) into deionized water, placing it on a magnetic stirrer and stirring it rapidly to obtain a CeO2 suspension; weighing Cu(NO3)2·3H2O in deionized water, adding it dropwise into the CeO2 suspension, and then adding (NH4)2CO3 aqueous solution dropwise until the pH value is 9, aging for 1 hour, centrifugally filtering, drying at 75°C for 12 hours, grinding into powder, and then placing the powder in a muffle furnace and heating it to 400°C at 5°C / min for calcining for 4 hours, and cooling it to room temperature to obtain NH4-CuO x / CeO2 catalyst.

6. The NH4-CuO prepared according to any one of claims 1 to 5 x / CeO2 catalyst.

7. NH4-CuO according to claim 6 x / CeO2 catalyst, characterized in that CuO x The mass ratio of CeO2 is 1:

100.

8. NH4-CuO according to claim 6 or 7 x Application of / CeO2 catalyst in removing high concentration CO.

9. The use according to claim 8, characterized in that: Here are the steps: 1) Weigh 200 mg NH4-CuO x / CeO2 catalyst in the reaction tube of the fixed bed reactor; 2) A xenon lamp light source with a power of 300W was added to apply full-spectrum illumination to the catalyst part of the reaction tube, and then three raw materials of 4% CO+He, 4% O2+He and 99.999% high-purity He were introduced at a total intake flow rate of 50mL / min. After catalysis, the tail gas was chromatographically separated and quantified by the equipped FID detector.

10. The use according to claim 9, characterized in that: In step 2), the concentration of CO is 10000 ppm; the catalytic time is 40 min; the tail gas is chromatographically separated and quantitatively detected by the equipped FID detector, and the conversion rate of CO reaches 90%.

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