Enhanced Low-Temperature CO₂ Methanation over Bimetallic Ni–Ru Catalysts

Abstract

Nickel-based catalysts are the most promising selection for CO2 methanation. But, it is challenging for monometallic Ni to achieve high CO2 conversion at low temperature. This study develops ceria-supported bimetallic Ni–Ru catalysts that are highly efficient for low-temperature methanation. A small amount of Ru (0.2 wt %) addition to Ni enables the intermetal interaction, and enhances the dispersion of Ni particles with a more active surface, consequently boosting the catalytic capacity for hydrogen activation and CO adsorption. The bimetallic Ni–Ru catalysts exhibit a more than 3-fold rate enhancement at low temperature for selective methanation of CO2 relative to the monometallic Ni/CeO2. Operando IR spectroscopy identifies the formate route as the major reaction mechanism over the monometallic Ni, and the presence of Ru in the bimetallic catalysts can induce the *CO-intermediate mechanistic pathway, contributing to the enhanced production of methane.