Manipulating the Coordination Environment of Cu Single Atoms via Regulating ZrO 2 Support Crystal Phases for Enhanced CO 2 Electroreduction

For electrochemical CO 2 reduction (ECR), high-precision manipulation of the single-atomic catalytic centers is significant and remains an issue. Here, we report a support crystal phase engineering (SCPE) strategy by regulating the crystal phase of the ZrO 2 support to modulate its interaction with Cu atomic centers, synergizing the coordination environment of Cu atoms and the local microenvironment for ECR. Specifically, tetragonal ZrO 2 (tZrO 2 ) supports a Cu 1 O 3 structure, and the rich bridging O atoms at the tZrO 2 surface could serve as basic sites. In contrast, the monoclinic ZrO 2 (mZrO 2 ) forming a Cu 1 O 4 structure has weak basicity. The Cu 1 O 3 –tZrO 2 site displays a high activity for ECR to methane, with 3.16 (FE CH 4 ) and 2.54 ( j CH 4 ) times higher than those of the Cu 1 O 4 –mZrO 2 counterpart. Density functional theory (DFT) and attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR–SEIRAS) reveal that the dynamic *OH on Cu 1 O 3 –tZrO 2 helps to significantly lower the Gibbs free-energy change (Δ G ) for the rate-determining step (RDS). The rich basic sites on tZrO 2 could also facilitate the adsorption and activation of CO 2 and create an H 2 O-expelling local microenvironment to suppress the competing hydrogen evolution reaction. Our work demonstrates a facile strategy to simultaneously manipulate the coordination environment of the active centers and the local microenvironment for the catalytic reaction.