Highly Dispersed Cu⁺-CeO₂ for Enhanced Solar- driven Dry Reforming of Methane over Ni-based Catalysts

Solar-driven dry reforming of methane (DRM) represents a sustainable route to convert greenhouse gases into syngas, which enables efficient solar energy storage and cascaded utilization. However, this process is often limited by insufficient reactivity and low light-to-fuel efficiency. Herein, by anchoring highly dispersed electron-deficient Cu⁺ species on defective CeO₂ (Cu⁺-CeO₂) via a high-temperature H₂ induction strategy (750°C), we designed an efficient Ni-based catalyst for solar-driven dry reforming of methane. The as-obtained Ni-Cu(750)/CeO₂ catalyst enhanced syngas production rate with a high light-to-fuel efficiency of 42.8% at 618°C, which significantly surpassed most state-of-the-art photothermal DRM catalysts even under milder conditions. Mechanism studies revealed that high-temperature H₂ treatment promoted the formation of Cu⁺-O_v-Ce³⁺ structures, which collectively modulated the electronic state to generate electron-enriched Ni active sites. The synergy between electron-rich Ni and Cu⁺-O_v-Ce³⁺ enhanced visible-light absorption and improved photothermal conversion. In situ DRIFTS studies demonstrated that Cu⁺-O_v-Ce³⁺ structures selectively promoted the rapid decomposition and desorption of the HCOO^* intermediate into CO, ensuring efficient active site cycling to achieve superior activity and stability in the photothermal DRM process. This work offers a generalized electronic structure engineering strategy for solar-driven greenhouse gases utilization.