Water-Mediated Selectivity Control of CH₃ OH versus CO/CH₄ in CO₂ Photoreduction on Single-Atom Implanted Nanotube...

Controllable methanol production in artificial photosynthesis is highly desirable due to its high energy density and ease of storage. Herein, single atom Fe is implanted into TiO₂ /SrTiO₃ (TSr) nanotube arrays by two-step anodization and Sr-induced crystallization. The resulting Fe-TSr with both single Fe reduction centers and dominant oxidation facets (001) contributes to efficient CO₂ photoreduction and water oxidation for controlled production of CH₃ OH and CO/CH₄ . The methanol yield can reach to 154.20 µmol g_cat ^-1 h^-1 with 98.90% selectivity by immersing all the catalyst in pure water, and the yield of CO/CH₄ is 147.48 µmol g_cat ^-1 h^-1 with >99.99% selectivity when the catalyst completely outside water. This CH₃ OH yield is 50 and 3 times higher than that of TiO₂ and TSr and stands among all the state-of-the-art catalysts. The facile gas-solid and gas-liquid-solid phase switch can selectively control CH₃ OH production from ≈0% (above H₂ O) to 98.90% (in H₂ O) via slowly immersing the catalyst into water, where abundant •OH and H₂ O around Fe sites play important role in selective CH₃ OH production. This work highlights a new insight for water-mediated CO₂ photoreduction to controllably produce CH₃ OH.