Periodic Macroporous K2Ta2O6 Fabricated for Photocatalytic Hydrogen Production from Pure Water Splitting.

Abstract

Periodic macroporous materials are extensively utilized in photocatalytic hydrogen production from water splitting owing to their smooth mass transfer and abundant active sites. Therefore, it is essential to develop highly stable materials featuring interconnected channels and appropriate surface states to enhance the photocatalytic capability. Periodic macroporous K₂Ta₂O₆ (PM-K₂Ta₂O₆) with a pyrochlore structure emerges as the ideal candidate to fulfill these requirements. Adding oxygen vacancies to PM-K₂Ta₂O₆ also makes it easier for localized energy levels to develop inside the bandgap, which improves light absorption and maximizes surface active sites. In comparison to nonporous K₂Ta₂O₆, PM-K₂Ta₂O₆ exhibits a broad light absorption band, rapid carrier transfer rates, prolonged photogenerated carrier lifetimes, high surface area, and abundant active sites, thus enabling stable photocatalytic hydrogen production from pure water. During surface photochemical reactions, the photogenerated electrons and holes in PM-K₂Ta₂O₆ are more readily trapped and subsequently participate in pure water splitting. The H₂ produced by PM-K₂Ta₂O₆ is 1285.91 μmol g^-1 in the 5 h H₂ production test. Herein, we propose a strategy for developing periodic macropore catalysts capable of efficiently decomposing pure water to produce H₂ without necessitating cocatalysts.