Synthesis of Ni-Co Bimetallic Catalyst with High Activity and Coking Resistance for Simulated Biogas Dry Reforming in a Constant Alkaline Chemical Environment

Abstract

Biogas dry reforming (BDR) technique has drawn widespread attention as an essential route for the utilization of renewable energy sources. It can produce highly valuable syngas from CO2 and CH4 conversion. However, Ni catalysts are very sensitive to coke deposition and sintering when catalyzing this process. It was discovered that highly dispersed Ni catalysts and bimetallic Ni catalysts can avoid carbon deposition and improve BDR reactivity. In this work, highly homogenous dispersed NiCo bimetallic catalysts was prepared via ammonia cycling method. By applying a series of characterization techniques to the catalysts, it can be found that ammonia reflux condensation is conductive to improve the dispersion of NiCo species and to strengthen the interaction of the active components with the carriers within catalysts. Most importantly, the 8Ni2Co/NH3-SiO2 catalyst showed the great activity and carbon deposition resistance during the 6 h test compared to the 8Ni/SiO2 and 8Ni/NH3-SiO2 catalysts. The conversion of CH4 and CO2 was 45.43% and 90.42%, respectively. Importantly, the carbon deposition on 8Ni2Co/NH3-SiO2 was 0.23%, which was higher than that on 8Ni/SiO2 catalyst (6.11%) prepared by isovolumetric impregnation. Consequently, our work may give insight into the appropriate design of high-performance catalysts for the BDR reaction.