Plasmon-driven synergy of hot electrons and oxygen vacancies enhances solar methane bi-reforming

Abstract

Solar-driven bi-reforming of methane (BRM) offers a compelling route to simultaneously valorize greenhouse gases CH4 and CO2 into syngas, but its practical implementation remains hindered by sluggish kinetics, catalyst deactivation, and low solar-to-fuel efficiency. Here, we report a plasmon-driven synergy of hot electrons and oxygen vacancies to enable efficient and stable solar BRM. The engineered plasmonic NiCo-La/CeO2 catalyst achieves an unprecedented syngas production rate of 240.31 mmol gcat−1 min−1 for H2 and 119.40 mmol gcat−1 min−1 for CO, together with a remarkable solar-to-fuel efficiency of 38.23% and negligible performance degradation over 500 h on-stream operation. A near-stoichiometric H2/CO ratio of 2.01 and high CO2 conversion of 62.93% are obtained, outperforming thermodynamic equilibrium limits under identical conditions. Mechanistically, localized surface plasmon resonance generates hot electrons that reprogram methane activation pathways, shifting from conventional *CH → *C routes to *CH + *OH → *CHOH → *CHO intermediates. Concurrently, plasmon excitation drives a dynamic oxygen-vacancy redox cycle that enhances CO2/H2O activation and suppresses carbon accumulation. This plasmon-driven synergy between hot electrons and oxygen vacancies establishes a potentially generalizable strategy for solar methane reforming and broader carbon feedstock conversion processes.