CeF_3分解制备CeO_2/CeF_3催化剂的丙烷氧化脱氢性能

Abstract

通过分解条件的控制从CEf3制备CEO2/CEf3催化剂.X-射线衍射(Xrd)、rAMAn、低能离子散射谱(lEIS)对制备得到的催化剂进行表征和定量估算,发现CEO2覆盖在CEf3上,随着焙烧温度的升高,CEf3催化剂由外而内分解程度加大.CEf3制备的CEO2/CEf3催化剂的丙烷氧化脱氢(OdHP)性能显著优于CEO2,CEO2覆盖层厚度的增加导致表面f/O摩尔比下降,f-隔离活性位的作用减弱,丙烯选择性由56.3%降低到42.2%.在反应过程中,CEf3核为表面CEO2覆层源源不断地提供f-,进而使催化剂保持较好的OdHP反应性能和稳定性.

A series of CeO2/CeF3catalysts were prepared by the decomposition of CeF3in air.Characterizations by XRD,Raman,and LEIS showed that CeO2covered on the CeF3surface.The degree of decomposition of CeF3increased toward the interior with increasing calcined temperature.With the increase of the calcined temperature,the surface F/O molar ratio decreased due to the formation of a thicker layer of CeO2.The CeO2/CeF3showed much better catalytic performance for the oxidative dehydrogenation of propane to propylene than CeO2,which may be due to that F-diluted the surface active oxygen species and decreased the selectivity of propylene.