PtSn/Ce_(1-x)Zr_(x)O_(2)催化二氧化碳氧化丙烷脱氢制丙烯的研究  

Oxidative dehydrogenation of propane to propene with carbon dioxide catalyzed by PtSn/Ce_(1-x)Zr_(x)O_(2)

作　　者：任星 杨国庆 刘忠文[1] Xing Ren;Guo-Qing Yang;Zhong-Wen Liu(Key Laboratory of Syngas Conversion of Shaanxi Province,School of Chemistry&Chemical Engineering,Shaanxi Normal University,Xi’an 710119,China)

机构地区：[1]陕西师范大学化学化工学院,陕西省合成气转化重点实验室,西安710119

出　　处：《中国科学：化学》2024年第10期1943-1954,共12页SCIENTIA SINICA Chimica

基　　金：国家自然科学基金(编号:22338010);中央高校基本科研业务费专项资金(编号:GK202406020)资助项目。

摘　　要：二氧化碳氧化丙烷脱氢(CO_(2)-ODP)被认为是一条节能、高效、环保的丙烯生产路线,但高性能催化剂是关键.依据催化CO_(2)-ODP涉及丙烷C–H键和CO_(2)分子协同活化的事实,本文从强化CO_(2)活化转化的角度,研究了氧缺陷对Pt Sn/Ce_(1-x)Zr_(x)O_(2)(x=0、0.4、0.5、0.7、1.0)催化CO_(2)-ODP性能的影响规律及其作用机制.结果表明,Pt Sn/Ce_(1-x)Zr_(x)O_(2)催化CO_(2)-ODP符合Mars-van-Krevelen氧化还原机理.与Pt Sn/Ce O_(2)相比,形成Ce_(1-x)Zr_(x)O_(2)固溶体,提高了催化剂中的氧缺陷含量、促进了Pt的分散、强化了CO_(2)补充晶格氧的能力,从而增强了其催化CO_(2)-ODP性能.其中,Pt Sn/Ce_(0.5)Zr_(0.5)O_(2)的丙烷转化率(36%)最高,可归因于其最大的Pt分散度、CO_(2)吸附量、氧缺陷浓度和CO_(2)补充晶格氧的能力.催化剂失活分析结果表明,Pt Sn/Ce_(0.5)Zr_(0.5)O_(2)吸附活化CO_(2)并补充晶格氧的能力最强,在维持氧化还原循环进行的基础上,还能够促进逆Boudouard反应的发生,消除积炭,稳定性最好.The oxidative dehydrogenation of propane with carbon dioxide (CO_(2)-ODP) is an energy-saving,efficient,and environmentally friendly process for propene production.However,the development of a high-performance catalyst is the key for its industrialization.Based on the understanding that the catalytic CO_(2)-ODP involves the simultaneous activation of propane and CO_(2) molecules,this work investigates the effect of oxygen defects on the catalytic performance of CO_(2)-ODP over Pt Sn/Ce_(1-x)Zr_(x)O_(2)(x=0,0.4,0.5,0.7 and 1.0) from the perspective of the enhanced CO_(2) activation.The results show that the CO_(2)-ODP reaction catalyzed by Pt Sn/Ce_(1-x)Zr_(x)O_(2) follows the Mars-van-Krevelen redox mechanism.In comparison with PtSn/CeO_(2),the introduction of Zr leads to the formation of Ce_(1-x)Zr_(x)O_(2) solid solution in the catalyst,which increases the content of oxygen defects.As a result,the dispersion of Pt,and the ability for the adsorption and activation of CO_(2) are increased,thus significantly enhance the catalytic performance for CO_(2)-ODP.Among them,the Pt Sn/Ce_(0.5)Zr_(0.5)O_(2) catalyst shows the most oxygen defects,the highest Pt dispersion,and the best ability for the adsorption and activation of CO_(2),so that can supplement the consumed lattice oxygen species over the catalyst during the reaction timely,and promote the redox cycles,resulting in the highest propane conversion (31%).The analysis of the catalyst deactivation indicates that Pt Sn/Ce_(0.5)Zr_(0.5)O_(2) shows the best ability for the adsorption and activation of CO_(2) to supplement the consumed lattice oxygen species,which not only maintains the redox cycles during the reaction,but also promotes the reverse Boudouard reaction and eliminates the carbon deposition,leading to the highest stability.

关 键 词：丙烷脱氢 二氧化碳 丙烯 铂基催化剂 铈锆固溶体 

分 类 号：O643.36[理学—物理化学] TQ221.212[理学—化学]