Liquid Metal Nanobiohybrids for High-Performance Solar-Driven Methanogenesis via Multi-Interface Engineering

Nanobiohybrids for solar-driven methanogenesis present a promising solution to the global energy crisis. However, conventional semiconductor-based nanobiohybrids face challenges such as limited tunability and poor biocompatibility, leading to undesirable spontaneous electron and proton transfer that compromise their structural stability and CH4 selectivity. Herein, we introduced eutectic gallium-indium alloys (EGaIn), featuring a self-limiting surface oxide layer surrounding the liquid metal core after sonication, integrated with Methanosarcina barkeri (M. b). The well-designed M. b-EGaIn nanobiohybrids exhibited superior performance, achieving a maximum CH4 yield of 455.64 ± 15.99 μmol g-1, long-term stability across four successive 7-day cycles, and remarkable CH4 selectivity of >99%. These improvements stem from enhanced proton-coupled electron transfer involving hydrogen atoms at the core-shell interface, further facilitated by the elevated expression of hydrogenases at the abiotic-biotic interface. This study provides an insightful concept for nanobiohybrid design through multi-interface engineering, advancing sustainable and scalable CO2-to-biofuel conversion under ambient conditions.