Preparation Of Supported Mo 2 C And Its Catalytic Performance For Carbon Dioxide Hydrogenation Reaction

In this work,α-Mo2C and β-Mo2C and supported Mo2C catalysts were prepared successfully by temperature programmed carbonization.method.The effects of supporters kind,loading amount and crystalline phases of the Mo2C on catalytic performance were tested in the hydrogenation of carbon dioxide to methanol over the supported Mo2C catalysts,and the reaction conditions were optimized.The results showed that 20β-Mo2C/M41 catalyst had the best catalytic performance,and the conversion of carbon dioxide of 4.5%and selectivity for methanol of 37.6%were obtained under optimized reaction conditions at 220 ℃ under 3.0 MPa and GHSV of 3600 mL/(h·g)after 14 h reaction.A serious of β-Mo2C/MCM-41 promoted by La2O3,CaO or Cu were prepared using co-impregnation and mechanical mixture method respectively,and catalytic performance in the hydrogenation of carbon dioxide to methanol was studied.The results showed the catalyst 5La2O320β-Mo2C/M41 with 5%La2O3 loading as promoter prepared by physically mixing method showed an outstanding catalytic performance.However,the 5CaO20β-Mo2C/M41 with 5%CaO loading as promoter sample prepared by co-impregnation method showed a higher selectivity for methanol,the conversion of carbon dioxide of 4.6%and selectivity of 42.6%for methanol were obtained after reaction of 14 h.The copper promoted β-Mo2C/M41 prepared by co-impregnation method gave the best catalytic performance,this is because that copper highly dispersed on the catalyst which shorten the distance between copper promoter and β-Mo2C active sites,and the transfer rate of activation hydrogen from copper particles to the β-Mo2C was increased,which led to improving the catalytic performance.The carbon dioxide conversion of 6.8%and selectivity for methanol of 53.0%were achieved after 14 h over the supported 15Cu20β-Mo2C/M41-I catalyst.In order to compare the catalytic performance of copper promoted 20β-Mo2C/M41-I catalyst and supported Pd catalyst in the hydrogenation of carbon dioxide to methanol,a series of supported Pd catalysts and some metal oxide such as CaO promoted catalysts were prepared by incipient-wetness impregnation method.The supporters and promoters variety,and Pd loading amounts in the catalytic performance were optimized,and Pd6Ca3/M41 sample was chose as the suitable catalyst.Moreover,the catalytic performance of 10Cu20β-Mo2C/M41-I andPd6Ca3/M41 catalysts were also investigated in the hydrogenation of carbon dioxide to methanol.The results showed that 10Cu20β-Mo2C/M41-I had an similar catalytic performance compared to Pd6Ca3/M41 catalyst after reaction of 40 h.What is more,supported Mo2C catalyst promoted by copper has shown the alternative potential applications to replace noble metal catalyst.