Studies on COx hydrogenation to methane over Rh-based catalysts

Nowadays, the eagerness of using the power-to-gas system as a solution to seasonal energy saving and renewable energy utilization difficulties, as well as increasing production of biofuel, has been raised. It is shown that in recent years, after a period of time with a reduction of methanation research activities, it has been increased. In this study, the utilization of rhodium (Rh) as one of the precious noble metals in the role of COx hydrogenation catalysis has been completely reviewed. It is demonstrated that however, Rh has a higher price in comparison with other noble catalysts, due to its activity and selective behavior to the main product of methanation, researchers tried to make Rh catalysis more reliable for industrial applications. Thus, an appropriate review of Rh catalyst preparation and modification methods has been provided via relevant case studies. It is shown that those supported and modified Rh-based catalysts have an acceptable performance at low temperature (< 200 degrees C) and pressure (1 bar) ranges which is mostly demanded due to economical issues. This study can be beneficial in the design and performance analysis of the COx methanation process using Rh-based catalysts in practical implementation.