尿素研磨燃烧法合成Ce_(0.8)Zr_(0.2)O_2固溶体对乙硫醇催化分解的研究

Ce_(0.8)Zr_(0.2)O_2 Solid Solution Rapidly Synthesized by Urea Grind Combustion Method with Ethylmercaptan(CH_3CH_2SH) Catalytic Decomposition

采用尿素研磨燃烧法快速制备Ce_(0.8)Zr_(0.2)O_2固溶体催化剂,考察不同焙烧温度下Ce_(0.8)Zr_(0.2)O_2固溶体常压下催化分解乙硫醇的活性。利用XRD,TEM,BET,H2-TPR,XPS和Raman等方法对催化剂的物化性质、表面结构进行研究。结果表明:Ce_(0.8)Zr_(0.2)O_2固溶体对乙硫醇催化降解有较好活性。在一定范围内升高焙烧温度有利于更多Zr4+进入Ce O2晶格,从而增加氧空位浓度,但过高的温度会使催化剂颗粒团聚,并降低催化剂表面吸附氧的相对含量,导致催化剂比表面积降低。600℃焙烧的Ce0.8Zr0.2O2固溶体表现出对乙硫醇催化分解最佳活性,得益于催化剂表面Ce3+浓度、氧空位浓度与比表面积的协同作用。一方面,这些表面Ce3+浓度与催化剂氧空位浓度,有利于氧迁移,对催化分解反应有促进作用,另一方面催化剂比表面积越大,越有利于反应物吸附、暴露更多活性位点,进而增加催化活性。

Urea grind combustion method was employed to rapidly synthesize ceria-zirconia nanoparticles for ethyl mercaptan （CH3CH2SH） catalytic decomposition. The effect of different calcination temperatures on the catalytic activity of Ce0.8Zr0.2O2 was investigated at atmospheric pressure. Its physical and chemical properties, and surface structure were characterized by XRD, TEM, BET, HE-TPR, XPS and Raman. The results showed that Ce0.8Zr0.2O2 solid solution prepared by urea grind combustion method exhibited excellent catalytic activity for CH3 CHzSH de- composition. More Zr^4＋ entered into the CeO： lattice by raising temperature at a certain range, leading to the in- crease in concentration of oxygen vacancies and enhancing the oxygen mobility. However, when the temperature was too high, the specific surface area of catalyst decreased and the concentration of surface adsorbed oxygen declined. The Ce0.8Zr0.2O2 solid solution calcined at 600℃ exhibited the best catalytic activity for decomposition of CH3CH2SH, which was attributed to the synergic effects among the Ce^3＋ concentration of catalyst surface, the in- creased concentration of oxygen vacancies and the larger specific surface area. Increasing the Ce^3＋ concentration of catalyst surface and concentration of oxygen vacancies is beneficial to the migration of oxygen and catalytic decomposition. Moreover, increasing specific surface area of catalyst can improve adsorption properties, exposing more active sites, and the catalytic activity is enhanced accordingly.