Electronic Synergy in Metal-Organic Framework-Derived CuNi Nanoclusters Enables Site-Specific Adsorption for Dynamically Tunable CO2-to-Syngas Conversion.

Electrochemical conversion of carbon dioxide (CO2) into syngas is an effective strategy for mitigating global warming and enabling carbon circularity. However, achieving a tunable and stable H2/CO ratio remains challenging due to the competitive adsorption and reaction kinetics of CO2 reduction and hydrogen evolution. Herein, a metal-organic framework-derived pyrolysis strategy constructs CuNi bimetallic nanoclusters on nitrogen-doped carbon (CuNi-NC), where Cu-Ni electronic interactions enable site-specific regulation of surface adsorption. The optimized Cu1Ni1-NC catalyst achieves a high FECO of 93.3% and a CO partial current density of -25.82 mA cm-2, with excellent stability over 28 h. Across a broad potential window from -0.51 to -0.81 V (vs RHE), CO-rich syngas with an H2/CO ratio around 0.37 is consistently produced. Furthermore, the syngas composition can be tuned by modulating the Cu/Ni ratio and applied potential, altering the relative contribution of CuNi active sites differing in electronic structure. Combined in situ attenuated total reflection Fourier transform infrared spectroscopy and density functional theory calculations reveal that Cu-Ni electronic synergy induces site-specific electronic modulation, optimizing the d-band center to stabilize *COOH intermediates and promote selective CO2-to-CO conversion. This work establishes a Cu-Ni bimetallic catalytic system for tunable syngas production and provides mechanistic insight into site-specific adsorption driven by electronic synergy.