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Selective hydrogenation of acetylene on SiO_2-supported ni-ga alloy and intermetallic compound

Journal of Energy Chemistry 2019年第2期28卷 40-49页

作者： Lei Wang Fengxu Li Yanjun Chen Jixiang Chen Tianjin Key Laboratory of Applied Catalysis Science and Technology Department of Catalysis Science and EngineeringSchool of Chemical Engineering and TechnologyTianjin University

ni/Si O_2 and bimetallic ni_xga/SiO_2 catalysts with different ni/ga atomic ratios(x = 10～2) were investigated for the selective hydrogenation of *** was found that ni_xga/SiO_2 showed higher selectivity to ethylene than ni/Si O_*** is attributed to the formation ni-ga alloy and ni3 ga intermetallic compound(IMC) where there was a charge transfer from ga to ni,which is favorable for reducing the adsorption strength and amount of ethylene on ni *** a result,the over-hydrogenation,the C–C bond hydrogenolysis and the polymerization were suppressed,and subsequently the selectivity to ethylene was *** the decrease of ni/ga atomic ratio,the activity and stability of the ni_xga/SiO_2 catalysts increased first and then decreased,while the ethylene selectivity tended to ***_5 ga/SiO_2 exhibited the best *** the conditions of 180 °C,0.1 MPa,and a reactant(1.0 vol% acetylene,5.0 vol% H_2 and 94 vol% N_2) with the space velocity of 36,000 m L h^(-1) g^(-1),the acetylene conversion maintained at 100% on ni_5 ga/SiO_2 during 120 h time on stream and the selectivity to ethylene was 75%～81%after reaction for 68 *** was also found that the formation of ni-ga alloy and ni_3 ga IMC suppressed the incorporation of carbon to form niCx,subsequently enhancing the catalyst ***,with increasing the ga content,the catalyst acid amount and strength tended to increase,which promoted the polymerization and carbon deposition and so the catalyst deactivation.