不同孔道结构的氧化硅负载钒氧化物催化丙烷氧化脱氢  

Propane Oxidative Dehydrogenation over Vanadia Catalysts Supported on Silicas with Different Pore Structures

作　　者：缪建文[1,2] 宋国华[3] 范以宁[2] 

机构地区：[1]南通大学化学化工学院,江苏南通226007 [2]南京大学化学化工学院,江苏南京210093 [3]南通大学理学院,江苏南通226001

出　　处：《催化学报》2009年第11期1143-1149,共7页

基　　金：国家重点基础研究发展计划(973计划;G1999022400);南通市应用研究计划项目(K2007018);留学回国人员科研启动基金(教外司留[2009]8号);江苏省基础研究计划(BK2009611)

摘　　要：采用固定床微型反应装置,结合催化剂的原位电子自旋共振光谱、程序升温表面反应和紫外漫反射光谱等技术,研究了丙烷氧化脱氢的介孔氧化硅负载钒氧化物催化剂的性能和表面氧物种的状态及其反应性.结果表明,催化剂载体孔结构是影响钒氧物种分散状态乃至催化性能的一个重要因素.SBA-15负载钒氧化物催化剂因具有较大的比表面积和较大的孔径,不仅具有较高的丙烷氧化脱氢催化活性,而且具有较高的丙烯选择性.复合型钒氧化物催化剂表面与V离子相连的晶格氧物种是丙烷氧化脱氢生成丙烯的主要活性物种,载体表面高度分散的钒氧物种具有较高的丙烷氧化脱氢催化活性.负载型钒氧化物催化剂晶格氧物种是丙烷氧化脱氢转化为丙稀的主要活性物种,CO2分子可以再生钒氧化物催化剂的晶格氧物种,同时它对丙烯的深度氧化作用较弱,因此在负载型钒氧化物催化剂上CO2氧化丙烷可高选择性地生成丙烯.The state and reactivity of surface oxygen species of mesoporous silica-supported vanadium oxide catalysts for oxidative dehydrogenation of propane have been investigated by microreactor tests combined with in-situ electron spin resonance, temperature-programrned surface reaction, and ultraviolet-visible diffuse reflectance spectroscopy. The pore diameter of the SBA-15, MCM-41, and silica gel supports exert great influences on the dispersion state of VOx species and the catalytic properties of the supported vanadium oxide catalysts. The SBA-15-supported vanadium oxide catalyst has the highest selectivity for propylene because of its larger pore diameter and higher surface area. Surface lattice oxygen species of the VOx/SBA-15 catalyst are main active species for oxidative dehydrogenation of propane to propylene. Highly dispersed VOx species have high catalytic reactivity for oxidative dehydrogenation of propane. CO2 can regenerate the lattice oxygen species of supported vanadium oxide catalysts. The high propylene selectivity for oxidative dehydrogenation of propane by CO2 on supported vanadium oxide catalysts is related to weaker oxidizing effect of CO2, which inhibits the direct C3H8 oxidation and the consecutive oxidation of C3H6 to COx.

关 键 词：丙烷 氧化脱氢 钒氧物种 SBA-15 电子自旋共振 程序升温表面反应 

分 类 号：O643.32[理学—物理化学]