Composition Optimization of Liquid Ga Support for Uniform Cu Dispersion with Sustainable Electroreduction of CO2 to CH4
Liquid metals (LMs) are promising catalyst systems due to their unique interfacial properties, yet migration and aggregation of active species cause performance degradation. Here, we report a composition optimization strategy using a Ga-In eutectic liquid metal support to reduce surface energy and achieve homogeneous incorporation of Cu species (GaIn-Cu). Comprehensive characterizations confirm uniform Cu dispersion, which inhibits migration and formation of CuGa2 intermetallic phases during CO2 electroreduction (CO2RR). The GaIn-10-Cu catalyst achieves a maximum CH4 Faradaic efficiency of 73.49% at -0.8 V vs. RHE, significantly higher than Ga-Cu (61.49%). Moreover, GaIn-10-Cu exhibits enhanced stability for CH4 generation over 40 h of continuous operation. In-situ spectroscopic studies reveal that GaIn-10-Cu favors formation and protonation of key *CHO and *OCH3 intermediates, steering selectivity toward CH4. This work demonstrates that tuning LM composition modulates catalytic site performance, offering a strategy for durable and selective LM-based electrocatalysts.