• • GaIn-10-Cu achieves 73.49% Faradaic efficiency for CH4 at -0.8 V vs. RHE, outperforming Ga-Cu (61.49%) by 12 percentage points, indicating superior selectivity for CO2-to-CH4 conversion.
• • The GaIn eutectic support enables continuous and uniform Cu dispersion, effectively inhibiting CuGa2 intermetallic phase formation during CO2RR, which is critical for maintaining catalytic activity over extended operation.
• • GaIn-10-Cu demonstrates enhanced stability for CH4 generation over 40 hours of continuous operation, a significant improvement over conventional catalysts that suffer from rapid deactivation.
• • In-situ spectroscopy identifies *CHO and *OCH3 as key intermediates, with GaIn-10-Cu favoring their formation and protonation, providing mechanistic insight for rational catalyst design.