High Stability of Ni-Co/SBA-15 Catalysts for CH4 Reforming with CO2

Abstract

A series of SBA-15 supported Ni-Co/SBA-15 bimetallic catalysts (CN-x, Ni = 13 wt%, Co wt% = x, x = 0, 2, 5, 8, 100) are prepared using a co-impregnation method. Catalyst screening with the reforming reaction shows that Ni-Co bimetallic catalysts have superior catalytic performance. In addition, the Ni-Co bimetallic catalyst with 2% Co content shows the best stability and the lowest carbon deposition rate (1.79 mgc.gcat−1.h−1) in 800-h time on stream. The results indicated that carbon deposition is still the main reason for deactivation. The addition of Co increases the basicity of catalysts and enhances the CO2 adsorption, which effectively reduce the carbon deposition rate, while the addition of Co excess will produce a large number of O species, leading to Co0 oxidation, accelerated catalysts deactivation. In addition, the Co species on Ni-Co/SBA-15 catalysts effectively changed the morphology of carbon deposition. Carbon deposit on Ni monometallic catalysts is mostly in the form of shell-like carbon making catalyst rapid deactivation, whereas the kind of whisker carbon species mainly exhibited on the surface of Ni-Co bimetallic catalysts possessed little toxicity.