Light-driven restructuring generates nanoisland NiIr alloy for efficient methane dry reforming.

The simultaneous utilization of methane and carbon dioxide via dry reforming holds promise for sustainable syngas production, yet conventional thermocatalytic processes suffer from energy-intensive operation and catalyst deactivation. Here, we report a light-driven methane dry reforming strategy utilizing sinter-resistant nano-island alloys catalyst, which are dynamically evolved from partially oxidized NiIr nanoclusters anchored on TiO2 under photoexcitation. In situ characterization reveals interfacial charge oscillations on the catalyst induce a support-Ni-Ir electron transfer pathway, stabilizing oxidized Ni linkages while electronically modulating surface Ir sites. This dual functionality promotes CHxO* intermediate formation, suppressing coking during 100-h operation under intermittent illumination. By decoupling photoelectric and photothermal contributions, we demonstrate that localized photogenerated electrons dominate balanced syngas production, whereas photothermal effects enhance molecular vibrations. The optimized catalyst achieves a syngas rate of 10841 mmol gcat-1 h-1 with 25.0% light-to-fuel efficiency, establishing a design paradigm for solar-driven alloy catalysts in greenhouse gas valorization.