Single-crystalline Ba<sub>x</sub>Sr<sub>1-x</sub>TaO<sub>2</sub>N solid-solution photocatalyst with low defect concentrations for solar-driven water splitting.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41587973.
- Also identified by DOI 10.1038/s41467-026-68848-9 and PMC identifier 12979620.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Perovskite-type tantalum-based oxynitride photocatalysts are promising candidates for water splitting due to their suitable band positions and extended light absorption beyond 600 nm. However, their associated photocatalytic activities and quantum yields remain relatively low. Here, we show that a nano-sized single-crystalline Ba<sub>x</sub>Sr<sub>1-x</sub>TaO<sub>2</sub>N solid-solution perovskite photocatalyst exhibits state-of-the-art activity in separate oxygen and hydrogen evolution half-reactions. The improved performance is attributed to the nanoscale particle sizes, as well as the reduced defect densities achieved by using a mixed precursor comprising TaS<sub>2</sub> and Ta<sub>3</sub>N<sub>5</sub>. The half-reaction activities can be modulated by applying a post-synthetic high-temperature treatment. Assessments of charge carrier dynamics, in conjunction with a mechanistic kinetic model, reveal that exponential-tail trap states are formed during this post-treatment. Such trap states, present on the photocatalyst surface, facilitate participation of holes during the oxygen evolution reaction. The development of such solid-solution photocatalysts broadens the range of potential materials for solar-driven hydrogen production. In addition, the present findings are expected to enable the selective tuning of bifunctional photocatalysts for either the hydrogen or oxygen evolution reaction.