Synergetic Interaction between Single-Atom Cu and Ga₂O₃ Enhances CO₂ Hydrogenation to Methanol over CuGaZrO_<i>x</i>

Abstract

A Cu-based catalyst has prospects for practical use in selective hydrogenation of CO2 to methanol. But the catalyst’s structural complexity renders the elucidation of the nature of active sites a challenge. This work reports CuGaZrOx solid solutions with tunable Cu size scales and synergetic interactions between active sites for methanol synthesis. Atomically dispersed Cu species (Cu1–O3) adjacent to the Zr site contribute to enhanced capacity for CO2 adsorption/activation, and Ga sites are primarily responsible for H2 dissociation over the CuGaZrOx solid solution with isolated Cu species. Further experimental and density functional theory (DFT) calculations reveal that the synergy between Cu and Ga species favors the hydrogenation of CO2 to form CH3OH via a formate pathway while suppressing undesired CO production. This work provides insight into the active site structure and mechanistic pathway over a CuGaZrOx solid solution and efficient catalyst design for CO2 hydrogenation to methanol.