Strategic Modulation of CO Intermediate Desorption Dynamics on Bimetallic Ni _x Cu _y @NC Catalyst: Synergistic Electrocatalysis for Sustainable CO ₂ Conversion

Bimetallic catalysts are appealing for electrochemical CO₂ reduction reaction (ECO2RR), yet the introduction of bimetallic sites leads to an incomprehensive understanding of the metal atom interaction and catalytic mechanism. In this study, a series of bimetallic Ni_xCu_y@NC catalysts with varied Ni to Cu weight ratios are prepared. The as-prepared Ni₂Cu₁@NC catalyst shows high carbon monoxide (CO) Faradaic efficiencies (FE_CO) over 90% in a broad potential range of -0.7 to -1.1 V (vs reversible hydrogen electrode (RHE)) with an exceptional durability of CO selectivity over 80% and a high partial current density of -44 mA cm^-2 at an extremely high potential of -1.3 V (vs RHE). The distinguished CO selectivity and activity are primarily attributed to the integration of Ni and Cu, which lowers the d-band center position and reconstructs the electronic structure according to the valence band spectra. More specifically, the downshifted d-band center position weakens the interaction strength with the *CO intermediate on the Ni₂Cu₁@NC catalyst's surface during the ECO2RR process, resulting in fast *CO desorption and high CO selectivity. This study provides researchers with a new insight for designing and optimizing the electrocatalysts for ECO2RR.