A general pyrolysis strategy to construct rare-earth oxide-stabilized high-density Ru single atom catalysts for efficient thermocatalytic CO2 methanation

Abstract

Single atom catalysts possess great potential for CO₂ conversion applications; however, their practical performance is often limited by low metal loadings, weak metal-support interactions and insufficient thermal stability. Herein, we propose a general pyrolysis strategy to construct high-density Ru single atom (ca. 5.4 wt%) on a rare earth element modified Al₂O₃ support. The as-prepared Ru_SA/Nd-Al₂O₃ exhibits superior catalytic performance, achieving a CH₄ production rate of 90.3 mmol g_cat⁻¹ h⁻¹, with a CO₂ conversion efficiency of 44.9 % and near-100 % CH₄ selectivity at 300 °C. A combination of detailed experimental characterization and density functional theory (DFT) calculations reveals the synergistic interaction between Ru single atoms and Nd modification. The presence of Nd₂O₃ not only facilitates the anchoring of high-density Ru species, thereby increasing the number of active sites, but also promotes the formation of reaction intermediates through its abundant oxygen vacancies and surface Lewis acid-base sites, ultimately leading to enhanced catalytic performance. This work elucidates the underlying interaction between single atom sites and the support, and provides a versatile strategy for constructing high-density single atom catalysts.