Study On CO Oxidation Reaction Catalyzed By Cu-based Oxide

With the increasing awareness of environmental protection and the strict requirements of environmental regulations in various countries,the elimination of carbon monoxide（CO）,an atmospheric pollutant,has been attached great attention from researchers.Nowadays,catalytic oxidation is considered to be one of the most effective and economical methods for eliminating CO,and the development and design of catalysts for CO oxidation reaction has been a hot topic of research.As a kind of classical catalytic materials,copper-based catalysts have shown a good application prospect in environmental management due to their low cost and variable valence,they are considered as an ideal catalyst for CO low-temperature oxidation reaction.This paper focuses on the controllable preparation of single-component copper oxide,two-component copper-cerium oxide catalysts and their catalytic performance for CO oxidation reaction,using XRD,TG,TEM,XPS,UV-Vis,TPR and other characterization techniques to systematically explore the relationship between the catalyst structure and catalytic performance.The main research contents are as follows.We prepared metal oxides by MOFs derivations using copper-based organic framework material（Cu BTC）as copper source.The MOFs was pyrolyzed in air（partially oxidising）and nitrogen atmospheres,respectively,to synthesize Cu_xO and Cu_xO@C catalyst embedded in a carbon matrix.It was evident from the characterisation that calcination atmosphere significantly affected the physical structure,morphology,specific surface area,chemical valence of copper species on the surface and redox property of the catalysts.Furthermore,we examined the effects of calcination temperature and calcination time on the Cu_xO and Cu_xO@C catalysts.The activity results showed Cu BTC had no catalytic active for CO oxidation until 190°C,while copper-based derivative materials had remarkable catalytic effects for CO oxidation.Noteworthy,Cu_xO-400（3）catalyst,calcinating at 400°C for 3 h in air atmosphere,showed the best catalytic performance and can completely oxidize CO at135°C at the space velocity of 24 000 m L·g_cat^-1·h^-1.We used the method of MOFs-derived to obtain bimetallic oxide Cu Ce-M catalyst.The results showed that the introduction of Ce can significantly improve the specific surface area of the catalyst,promote the dispersion of Cu species,enhance the redox ability of the catalyst and the catalytic oxidation performance of CO.The activity results showed Cu Ce-M can catalyze 95%CO oxidation at 90°C.At the same time,we used a co-precipitation method to prepare Cu Ce-C catalyst and investigated the effect of the preparation method on the Cu Ce-oxide catalysts.The results showed that the Cu Ce-C catalyst had a better catalytic performance for CO oxidation reaction because of its smaller particle size and better low temperature redox property,and Cu Ce-C can catalyze 100%CO oxidation at 90°C.Subsequently,we added hydrogen peroxide solution to adjust the surface properties and internal structure of Cu Ce-oxide catalyst in the process of co-precipitation.The results showed that the addition of hydrogen peroxide was beneficial for the preparation of Cu Ce-H catalysts with small particle size,large specific surface area,more abundant surface oxygen vacancies and highly dispersed copper species;when the molar ratio of Ce/Cu was 3 and the addition of hydrogen peroxide with a molar ratio of H₂O₂/（Ce+Cu）was 3,Cu Ce-H3 sample showed the best catalytic oxidation performance,and CO can be completely removed by oxidation at 80°C at the vacancy rate of 24 000 m L·g_cat^-1·h^-1.