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.