A Ni-O-Ag photothermal catalyst enables 103-m ² artificial photosynthesis with >17% solar-to-chemical energy conversion efficiency

The scalable artificial photosynthesis composed of photovoltaic electrolysis and photothermal catalysis is limited by inefficient photothermal CO₂ hydrogenation under weak sunlight irradiation. Herein, NiO nanosheets supported with Ag single atoms [two-dimensional (2D) Ni₁Ag_0.02O₁] are synthesized for photothermal CO₂ hydrogenation to achieve 1065 mmol g^-1 hour^-1 of CO production rate under 1-sun irradiation. This performance is attributed to the coupling effect of Ag-O-Ni sites to enhance the hydrogenation of CO₂ and weaken the CO adsorption, resulting in 1434 mmol g^-1 hour^-1 of CO yield at 300°C. Furthermore, we integrate the 2D Ni₁Ag_0.02O₁-supported photothermal reverse water-gas shift reaction with commercial photovoltaic electrolytic water splitting to construct a 103-m² scale artificial photosynthesis system (CO₂ + H₂O → CO + H₂ + O₂), which achieves more than 22 m³/day of green syngas with an adjustable H₂/CO ratio (0.4-3) and a photochemical energy conversion efficiency of >17%. This research charts a promising course for designing practical, natural sunlight-driven artificial photosynthesis systems.