TiH2-supported Ru catalyst with unusual electron transfer behaviour for highly efficient carbon dioxide methanation at low temperature

Abstract

Catalytic CO₂ methanation is of particular significance and growing interest due to its applications in many important industrial fields. The development of advanced heterogeneous catalysts for CO₂ methanation depends predominantly on the rational regulation of metal–support interaction (MSI), which remains challenging despite recent progress. Here, we develop a new heterogeneous catalyst, TiH₂-supported Ru nanoparticles (NPs), which features notable electron transfer from the TiH₂ support to Ru NPs and enhanced capability of CO intermediate activation for CO₂ methanation, distinct from TiO₂-supported Ru catalysts synthesized under similar mild conditions. The electron transfer behavior and hydrogen spillover effect in TiH₂-supported Ru NPs (denoted as mRTH, where m refers to the mass loading of the RuCl₃ precursor in mg) are optimized at a moderate Ru loading level of 9.8 wt% in 100RTH, where the impacts of Ru loading on CO intermediate activation, H₂ activation and catalyst surface hydration are synergistically balanced. When evaluated at 200 °C under 4 bar pressure, 100RTH delivers a notable CH₄ selectivity of 99.8% and a superior CH₄ production rate of 168.7 mmol h⁻¹ g_Ru⁻¹, which is 21.1 times more active than pure Ru NPs. Our work provides valuable insights into the MSI-directed development of heterogeneous catalysts for highly efficient CO₂ conversion and utilization.