Pt颗粒负载对CeO2臭氧催化氧化甲苯的增强作用

Enhancement effect of Pt modification on CeO2 on catalytic ozonation of toluene

通过铂颗粒吸附法制备得到Pt/CeO2催化剂应用于臭氧催化氧化甲苯反应,研究了Pt颗粒负载对CeO2臭氧催化氧化甲苯的增强作用.采用氢气程序升温还原(H2⁃TPR)、氧气程序升温脱附(O2⁃TPD)、X射线光电子能谱(XPS)和拉曼光谱(Raman)等手段对催化剂进行表征,结果显示,CeO2负载Pt颗粒后,Pt与CeO2存在相互作用,提高了CeO2上氧空位的含量.臭氧分解实验证实了Pt/CeO2催化剂具有更好的臭氧分解性能.臭氧催化氧化甲苯评价结果表明,Pt/CeO2具有比CeO2更优异的催化性能,在80℃时甲苯降解率、CO2产率和臭氧分解率分别达到92.3%、92.1%和99.9%.原位拉曼进一步研究了臭氧分解生成的氧物种种类及含量,以及甲苯存在时氧物种的变化,结果表明,臭氧在氧空位上分解产生的过氧物种较为稳定,是氧化甲苯的重要活性物质.因此,Pt颗粒负载在CeO2上能增强臭氧在催化剂上分解,并形成更多过氧物种,最终提升臭氧催化氧化甲苯的性能.

The Pt/CeO2 catalyst was synthesized via platinum particle adsorption method and its enhanced performance was compared with CeO2 during catalytic oxidation of toluene by ozone.The catalysts were characterized by hydrogen temperature programmed reduction(H2⁃TPR),oxygen temperature programmed desorption(O2⁃TPD),X⁃ray photoelectron spectroscopy(XPS)and Raman.The results showed that the strong interaction between Pt and CeO2 increased the amount of oxygen vacancy in CeO2.Compared with CeO2,Pt/CeO2 exhibited higher catalytic activity towards both toluene ozonation and ozone decomposition.The toluene removal,CO2 yield and ozone decomposition of Pt/CeO2 reached 92.3%,92.1%and 99.9%at 80℃,respectively.In situ Raman was used for further studying the species and content of oxygen species generated from ozone decomposition and their evolution with or without toluene.The loading of Pt particles on CeO2 can promote ozone decomposition to produce more active peroxide species,and thus greatly improve the performance of catalytic ozonation of toluene.