阅读说明：本技术 高效稳定的VOCs氧化降解用Pt/CeO2-TiO2催化剂的制备方法 (Efficient and stable Pt/CeO for oxidative degradation of VOCs2-TiO2Process for preparing catalyst ) 是由 周仁贤 石壹军 王佳露 于 2020-05-27 设计创作，主要内容包括：本发明提供了一种高效稳定的VOCs氧化降解用Pt/CeO<Sub>2</Sub>-TiO<Sub>2</Sub>催化剂的制备方法,以廉价的氯化亚铈或硝酸亚铈、四氯化钛、少量的氯铂酸为原料,采用沉淀法制备CeO<Sub>2</Sub>-TiO<Sub>2</Sub>复合氧化物载体,采用无电子沉积法负载Pt制得Pt/CeO<Sub>2</Sub>-TiO<Sub>2</Sub>催化剂,催化剂中CeO<Sub>2</Sub>/TiO<Sub>2</Sub>的最佳摩尔比为4:1～1:1。催化剂制备工艺简单,成本低。本发明制备所得的催化剂特别适用于含氯VOCs或与含苯和正己烷等非含氯VOCs共存的有机废气催化燃烧,催化剂对二氯乙烷、正己烷的完全氧化温度仅分别为290℃和140℃左右,它们共存时催化活性无下降趋势,具有优异的低温催化氧化降解活性和稳定性,应用前景良好。(The invention provides a high-efficiency stable Pt/CeO for VOCs oxidative degradation 2 ‑TiO 2 The preparation method of the catalyst adopts a precipitation method to prepare CeO by taking cheap cerous chloride or cerous nitrate, titanium tetrachloride and a small amount of chloroplatinic acid as raw materials 2 ‑TiO 2 The Pt/CeO is prepared by loading Pt on the composite oxide carrier by adopting an electroless deposition method 2 ‑TiO 2 Catalyst, CeO in catalyst 2 /TiO 2 The optimal molar ratio of (A) is 4:1 to 1: 1. The catalyst has simple preparation process and low cost. The catalyst prepared by the invention is particularly suitable for catalyzing organic waste gas containing chlorine VOCs or coexisting with non-chlorine VOCs containing benzene, normal hexane and the likeThe complete oxidation temperature of the catalyst to dichloroethane and n-hexane is only about 290 ℃ and 140 ℃ respectively, the catalytic activity of the catalyst does not decrease when the dichloroethane and the n-hexane coexist, and the catalyst has excellent low-temperature catalytic oxidation degradation activity and stability and good application prospect.)

1. Efficient and stable Pt/CeO for oxidative degradation of VOCs₂-TiO₂The preparation method of the catalyst is characterized in that chloroplatinic acid (H) is used₂PtCl₆) Cerium salt, titanium tetrachloride (TiCl)₄) Is prepared from CeO by precipitation₂-TiO₂The Pt/CeO is prepared by loading Pt on the composite oxide carrier by adopting an electroless deposition method₂-TiO₂Catalyst, CeO in catalyst₂/TiO₂The molar ratio of (a) to (b) is 4: 1-1: 4, and the preparation method specifically comprises the following steps:

the first step is as follows: as described in CeO₂/TiO₂Adding inorganic acid into the aqueous solution of cerium salt, stirring uniformly at 0 ℃, and dripping TiCl₄Continuously stirring the solution until the solution is transparent, and then dropwise adding ammonia water (NH) with the concentration of 0.5-2.0 mol/L under vigorous stirring₃·H₂O) until the pH value of the solution reaches 9.5-11.0, standing and aging for 6-12 hours at room temperature, then filtering, washing with deionized water for multiple times until the filtrate is neutral, drying at 80-100 ℃, roasting at 400-550 ℃ for 1-4 hours, and obtaining CeO₂-TiO₂A composite oxide;

the second step is that: mixing the powder CeO₂-TiO₂Dispersing the composite oxide in deionized water, adding vitamin C (Vc) after uniformly stirring, washing for a plurality of times by using the deionized water after continuously stirring for 1-2 hours, and then adding H₂PtCl₆Stirring the aqueous solution for 2-4 hours, filtering, washing with deionized water for multiple times until no Cl is detected in the filtrate^-Drying at 60-100 ℃, and roasting at 400-500 ℃ for 1-3 hours to obtain Pt/CeO₂-TiO₂A catalyst.

2. Pt/CeO according to claim 1₂-TiO₂The preparation method of the catalyst is characterized in that the CeO₂/TiO₂The optimal molar ratio of (A) is 4:1 to 1: 1.

3. Pt/CeO according to claim 1₂-TiO₂The preparation method of the catalyst is characterized in that the cerium salt is cerous nitrate (Ce (NO)₃)₃·6H₂O) or cerous chloride (CeCl)₃·7H₂O).

4. Pt/CeO according to claim 1₂-TiO₂The preparation method of the catalyst is characterized in that the inorganic acid is hydrochloric acid (HCl).

5. According to claim1 said Pt/CeO₂-TiO₂The preparation method of the catalyst is characterized in that the Pt loaded by the electroless deposition method is to pretreat CeO by using Vc solution₂-TiO₂Composite oxide support, Re-impregnation H₂PtCl₆Loading Pt; the addition amount of Vc is as follows: CeO (CeO)₂The molar ratio to Vc is less than 3.0.

Technical Field

The invention relates to a method for preparing a catalyst, in particular to a method for preparing a catalystIs high-efficiency and stable Pt/CeO for the oxidative degradation of VOCs₂-TiO₂A method for preparing the catalyst.

Background

Volatile Organic Compounds (VOCs) are compounds which are extremely harmful to the environment and human health, are widely derived from waste gas emission in industries such as petrochemical production, printing and coating, food and rubber production and the like, and are often complex in components and large in exhaust amount, while a catalytic combustion technology is one of important and effective means for purifying VOCs pollutants, and development of a catalyst which is low in cost, efficient, stable and good in broad spectrum is a key for realizing application of the technology. CeO (CeO)₂-TiO₂The composite oxide has rich weak and medium strong acid centers, is very favorable for the catalytic degradation of chlorine-Containing VOCs (CVOCs), has good tolerance, but when the waste gas contains other non-chlorine-containing VOCs (such as normal hexane, benzene and the like), the CeO is easy to be caused due to the insufficient oxidizing capability of the catalyst₂-TiO₂The catalyst deposits carbon to affect the stability of the catalyst. The catalyst has good acidity and oxidizability, can promote deep oxidation of intermediate products while maintaining the environment favorable for CVOCs to absorb broken bonds, and has high oxidation performance on other non-chlorine-containing VOCs. Therefore, the development of a highly stable and highly adaptable catalyst for combustion of organic exhaust gas has become a significant issue for the wide application of catalytic combustion technology.

Disclosure of Invention

The invention aims to provide an efficient and stable organic waste gas combustion catalyst, in particular to Pt/CeO₂-TiO₂A method for preparing the catalyst. The invention is realized by the following technical scheme:

the invention discloses a high-efficiency stable Pt/CeO for VOCs oxidative degradation₂-TiO₂Method for preparing catalyst from chloroplatinic acid (H)₂PtCl₆) Cerium salt, titanium tetrachloride (TiCl)₄) Is prepared from CeO by precipitation₂-TiO₂The Pt/CeO is prepared by loading Pt on the composite oxide carrier by adopting an electroless deposition method₂-TiO₂Catalyst, CeO in catalyst₂/TiO₂The molar ratio of (a) to (b) is 4: 1-1: 4, and the preparation method specifically comprises the following steps:

the first step is as follows: as described in CeO₂/TiO₂Adding inorganic acid into the aqueous solution of cerium salt, stirring uniformly at 0 ℃, and dripping TiCl₄Continuously stirring the solution until the solution is transparent, and then dropwise adding ammonia water (NH) with the concentration of 0.5-2.0 mol/L under vigorous stirring₃·H₂O) until the pH value of the solution reaches 9.5-11.0, standing and aging for 6-12 hours at room temperature, then filtering, washing with deionized water for multiple times until the filtrate is neutral, drying at 80-100 ℃, roasting at 400-550 ℃ for 1-4 hours, and obtaining CeO₂-TiO₂A composite oxide;

the second step is that: mixing the powder CeO₂-TiO₂Dispersing the composite oxide in deionized water, adding vitamin C (Vc) after uniformly stirring, washing for a plurality of times by using the deionized water after continuously stirring for 1-2 hours, and then adding H₂PtCl₆Stirring the aqueous solution for 2-4 hours, filtering, washing with deionized water for multiple times until no Cl is detected in the filtrate^-Drying at 60-100 ℃, and roasting at 400-500 ℃ for 1-3 hours to obtain Pt/CeO₂-TiO₂A catalyst.

As a further improvement, the CeO of the present invention₂/TiO₂The optimal molar ratio of (A) is 4:1 to 1: 1.

As a further improvement, the cerium salt of the invention is cerous nitrate (Ce (NO)₃)₃·6H₂O) or cerous chloride (CeCl)₃·7H₂O).

As a further improvement, the inorganic acid of the invention is hydrochloric acid (HCl).

As a further improvement, the Pt loaded by the electroless deposition method of the invention means that CeO is pretreated by Vc solution₂-TiO₂Composite oxide support, Re-impregnation H₂PtCl₆Loading Pt; the addition amount of Vc is as follows: CeO (CeO)₂The molar ratio to Vc is less than 3.0.

The invention provides Pt/CeO₂-TiO₂The preparation method of the catalyst has the advantages that:

cheap cerous chloride or cerous nitrate, titanium tetrachloride and small amount of chloroplatinic acid are used as raw materials to prepare CeO by precipitation method₂-TiO₂The Pt/CeO is prepared by loading Pt on the composite oxide carrier by adopting an electroless deposition method₂-TiO₂Catalyst, CeO in catalyst₂/TiO₂The optimal molar ratio of the organic waste gas to the organic waste gas is 4: 1-1: 1, the preparation process is simple, the catalyst cost is low, and the organic waste gas combustion catalyst is efficient and stable. The catalyst prepared by the invention is particularly suitable for catalytic combustion of organic waste gas containing chlorine-containing VOCs or coexisting with non-chlorine-containing VOCs containing benzene, n-hexane and the like, the complete oxidation temperature of the catalyst to dichloroethane and n-hexane is only about 290 ℃ and 140 ℃ respectively, the catalytic activity of the catalyst is not reduced when the dichloroethane and n-hexane coexist, and the catalyst has excellent low-temperature catalytic oxidation degradation activity and stability and good application prospect.

The specific implementation mode is as follows:

the technical solution of the present invention is further illustrated by the following specific examples: