Cu–Sb Atomic Pair Site in Metal Halide Perovskite for CO2 Reduction to Methanol

Electrochemical conversion of CO₂ into methanol has received extensive attention in recent years since methanol is an efficient energy carrier and industrial feedstock. However, the selectivity to methanol remains unsatisfied. In this work, Sb-doped Cs₃Cu₂I₅ is first and rationally developed for CO₂ electrochemical reduction, achieving remarkable high selectivity of methanol. UV-vis absorption, X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations show that the Sb dopants narrow the band gap of Cs₃Cu₂I₅ and enhance the metal-ligand hybridization due to the introduction of Sb 5p orbitals, which accordingly enhance the charge transfer. In addition, the Cu-Sb pair in Sb@Cs₃Cu₂I₅ perovskite synergistically catalyzes the CO₂ conversion. The Cu sites serve for CO₂ absorption and activation, while the Sb sites stabilize the intermediate *OCH₂ through the Sb-O bond due to superior oxygen affinity. The plasma-treated sample with electron-deficient Sb exhibits the best methanol selectivity as high as 88.38%. This work provides new insight into highly efficient metal halide perovskite-based catalysts for CO₂ electrochemical conversion.