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 efficiency of approximately 70 ± 7%. The synthesis temperature yielding the highest activity was lower for photocatalytic O2 evolution than for photoelectrochemical O2 evolution. This work demonstrates the applicability of the flux method to the synthesis of well-crystallized oxysulfides having various particle sizes and intended for different uses.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films