Plate-like Sm2Ti2S2O5 Particles Prepared by a Flux-Assisted One-Step Synthesis for the Evolution of O2 from Aqueous Solutions by Both Photocatalytic and Photoelectrochemical Reactions

Abstract

Sm2Ti2S2O5 (STSO) is a visible-light-responsive oxysulfide semiconductor photocatalyst with applications to water splitting. In this work, plate-like STSO particles were synthesized through a flux-assisted one-step method at various temperatures. The activities of these materials during photocatalytic and photoelectrochemical O2 evolution from aqueous solutions were investigated. Single-phase STSO with a single crystal habit was produced at 923 K, which is approximately 200 K lower than the temperatures required for previously reported methods, such as solid-state reactions and thermal sulfurization under a H2S flow. The STSO sample synthesized at the optimal temperature exhibited an AQE of 1.3 ± 0.2% at 420 nm during photocatalytic sacrificial O2 evolution. This efficiency is twice the values reported for specimens prepared using conventional methods. An STSO/Ti/Sn electrode fabricated by the particle transfer method generated a photoanodic current and evolved O2 by water oxidation with a Faradaic effici...