Improving the Performance of a Co-CeO2 Catalyst for Hydrogen Production via Water Gas Shift Reaction by Addition of Transition Metal Oxides

The hydrogen production from combustible waste is attracting attention because of the increasing interest in clean and renewable hydrogen production. To produce hydrogen from combustible waste, gasification and water gas shift reaction processes are required. Syngas, which mainly consists of hydrogen and carbon monoxide, is generated by gasification of combustible waste. The water gas shift reaction is applied to produce additional hydrogen from carbon monoxide in waste-derived syngas. The performance of catalysts is important to achieve reasonable process efficiency. Co-based catalysts were applied to the water gas shift reaction because Co has significant capability for CO oxidation and high reaction rates when it is used as an active metal. However, it was necessary to enhance the stability of Co-based catalysts. Here, different transition metal oxides (TiO2, ZrO2, V2O5, and Nb2O5) are used as promoters to enhance the Co-CeO2 catalyst performance. To investigate the effects of promoters on the catalytic performance, various properties are characterized. According to the analysis results, the physicochemical properties, which determine the catalytic performance, were influenced by the addition of transition metal oxides. Among the synthesized catalysts, the Nb2O5-promoted Co-CeO2 catalyst exhibited the best catalytic performance. As a result, the Nb2O5 promoter is the most effective to improve the catalytic activity and stability of the Co-CeO2 catalyst for high-temperature water gas shift reaction to produce hydrogen from waste-derived syngas. The higher CO conversion is related to the numerous oxygen vacancies and high Co dispersion, while stability is related to strong interactions between Co and the support. These findings are expected to aid the development of catalysts by confirming physicochemical properties relating with catalytic performance.