In基二氧化碳氧化丙烷脱氢催化剂的研究

Structural-Activity Relationship of Indium-Based Catalysts for CO_(2) Oxidative Propane Dehydrogenation

二氧化碳氧化丙烷脱氢增产丙烯是提高丙烷脱氢单程转化率与二氧化碳资源化利用的重要途经,探究高效的非贵金属环保型催化剂对工业界和科学界均有重要意义.采用不同合成方法制备了系列In基催化剂,通过X射线衍射、拉曼、紫外可见漫反射吸收光谱、H_(2)-程序升温还原、电镜图像观测了In活性位结构.关联活性数据得出,具有InO_(6)结构的In_(2)O_(3)颗粒在CO_(2)氧化丙烷脱氢气氛中能够发生氧化还原循环,从而驱动CO_(2)及丙烷分子的活化,而水热法合成样品中不含该InO_(6)结构,因此不具备CO_(2)活化能力.此外,十元环MFI型Silicalite-1沸石相比十二元环的Si-Beta沸石载体能够促进CO_(2)的吸附,也提高了CO_(2)对丙烷分子活化的促进作用.

CO_(2)assisted propane dehydrogenation(CO_(2)-PDH)is an important way to improve the per pass conversion of propane and the resource utilization of CO_(2).It is of industrial and scientific interest to explore efficient and nontoxic CO_(2)-PDH catalysts Herein,a series of indium-based catalysts with different synthesis methods were prepared.The indium site structure was investigated by X-ray diffraction,Raman,H_(2)temperature programmed reduction and scanning electron microscopy measurements.By correlating with the activity data,one could conclude that the impregnated In/S1 catalysts contain InOx cluster and In_(2)O_(3)particles with InO_(6)structural moiety,which undergoing the In^(δ+)←→In^(0)redox cycle during the reaction.In comparison,the hydrothermal synthesized In-S1 sample do not contain this InO_(6)structure.Such redox cycle derived by InO_(6)coordination play an important role in CO_(2)-PDH process.Besides,the ten membered silicalite-1 zeolite is more favorable for CO_(2)adsorption/activation compared with the twelve membered BEA topological Si-Beta zeolite,because the In/S1 shows superior activity than 5In/Si-Beta counterpart.