Design an in-situ reduction of Ni/C–SiO2 catalyst and new insights into pretreatment effect for CH4–CO2 reforming reaction

Abstract

A series of Ni/C–SiO2 catalysts with high Ni0 dispersion were prepared through impregnation method with glucose as the carbon source as well as the reduction agent. During the calcination process under N2 atmosphere, the generated reductive substances, like CO, H2 and carbon derived from decomposition and carbonization of glucose, which could transform NiO into Ni0 particles completely, according to XRD and H2-TPR analysis. To improve the catalytic performance of CH4–CO2 reforming reaction, the Ni/C–SiO2 catalyst was further pretreated under N2, H2 and CO2 atmosphere prior to the reaction. The CO2 pretreated catalyst exhibited excellent catalytic activity and superior stability comparing with other catalysts. A rapid deactivation occurred on the Ni/SiO2 catalyst prepared by traditional impregnation method during 10 h test. Reversely, the CO2 pretreated catalyst maintained a high CH4, CO2 and Ctotal conversion (71.1, 81.1 and 77.1%, respectively) during a 40 h time-on-stream test, which was attributed to homogenous Ni particles dispersion and strong interaction between metal and support. This methodology opens up a possibility for diversification in carbon-silica composite catalysts. The working catalyst without further reduction process will give the required metal-support interaction for the novel synthesis.