A band-to-band transition visible-light-responsive anatase titania photocatalyst by N,F-codoping for water splitting and CO2 reduction

Abstract

To efficiently utilize solar energy and catalyze the water splitting reaction under visible-light, a novel strategy of first nitridation and subsequent calcination post-treatment methods is developed to prepare N,F-codoped TiO₂ (TNOF) photocatalysts in this work. The prepared sample exhibits obvious band-to-band absorption with an edge up to ca. 580 nm. After calcinating the nitrided sample at low temperature in air, the Ti³⁺ defects, which could trap photo-generated electrons during photocatalysis, would be significantly reduced. Under visible-light irradiation, the TNOF photocatalyst presents excellent water oxidation performance in AgNO₃ aqueous solution or Fe³⁺ reversible electron acceptor. Based on the obtained TNOF sample, an efficient Z-scheme water overall splitting system is successfully constructed combining with a known Ru/SrTiO₃:Rh H₂-evolution photocatalyst. Moreover, the TNOF photocatalysts also show good visible-light-driven water reduction and CO₂ reduction activities. This work presents a novel strategy to prepare nitrogen-incorporated oxide photocatalysts with low defect concentrations for photocatalytic applications.