Effect of Various Prepared Method on Catalytic Performance of Cu-Mn-Si/HZSM-5 Catalyst for CO_2 Hydrogenation

Abstract

分别采用物理混和、共沉积法和超声共沉积法制备了Cu-Mn-Si/HZSM-5复合催化剂,并用XRD、BET、H2-TPR、H2-TPD和NH3-TPD等手段进行了表征,考察3种制备方法对催化剂催化加氢性能的影响。结果表明:超声共沉积法制备的Cu-Mn-Si/HZSM-5催化剂颗粒均匀、粒径小、催化性能最好。H2-TPR、H2-TPD和NH3-TPD分析表明,采用超声共沉积法制备催化剂,更能促进Cu(Ⅰ)、Cu(Ⅱ)之间的相互转换,增强了铜锰复合氧化物相互作用,有利于催化剂表面活性物种Cu+形成。同时,增强了对H2的吸附强度,使表面的酸度增强,促进了催化剂活性的提高。Cu-Mn-Si/HZSM-5 catalysts were prepared via the physical hybrid method,co-precipitation method and Ultrasonic co-precipitation method,and these catalysts were characterized by XRD,BET,H2-TPR,H2-TPDand NH3-TPD to analyse catalytic performance of the catalysts.The results showed that although sonication can not obviously change the physical structure of catalysts,it can make partical uniform and tiny,and.The results indicated that Cu-MnSi/HZSM-5 catalysts prepared by the Ultrasonic co-precipitation method had uniform grain,small grain size and the best catalytic capacity.H2-TPR,H2-TPD and NH3-TPD results suggested that it promote the creation of Cu+ on surface of catalyst and enhance the interaction of copper-manganese compound oxide so that active specie Cu are difficult to be reduced by ultrasonic co-precipitation method.At the same time,adsorption sites for H2 were increased,acidity of surface of catalyst was increased and acid sites were stronger,promoting enhancement of activity of catalyst

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