Single phase of perovskite YTaON2 synthesized for photocatalytic water reduction and oxidation under visible-light irradiation

Abstract

The development of visible-light-responsive perovskite-type oxynitrides has inspired extensive interest in promising water splitting to produce hydrogen due to their suitable band structures and wide visible-light response, but it is still challenging to synthesize the single-phase perovskite structure YTaON₂. Here, we synthesized the pure perovskite YTaON₂ by a Mg-powder-assisted nitridation strategy, and its physical/chemical properties were investigated in detail. It was interesting to note that the homogenous nitrogen element dispersion together with the high content of nitrogen contributed to its narrow band gap of 2.1 eV with an absorption edge of ca. 600 nm, while experimental measurements revealed its bifunctionalities for water reduction and oxidation under visible-light irradiation in the presence of a corresponding electron donor and acceptor. On this basis, a Z-scheme overall water splitting system was successfully constructed by employing the Pt/YTaON₂ as the H₂-evolution photocatalyst together with PtO_x/WO₃ and IO₃⁻/I⁻ as the O₂-evolution photocatalyst and shuttle ions, respectively. Our results enrich the database of photocatalytic materials and extend the application of the Mg-powder-assisted nitridation strategy.