Single-atomic-site platinum steers photogenerated charge carrier lifetime of hematite nanoflakes for photoelectrochemical water splitting.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37156781.
- Also identified by DOI 10.1038/s41467-023-38343-6 and PMC identifier 10167323.
- 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
Although much effort has been devoted to improving photoelectrochemical water splitting of hematite (α-Fe<sub>2</sub>O<sub>3</sub>) due to its high theoretical solar-to-hydrogen conversion efficiency of 15.5%, the low applied bias photon-to-current efficiency remains a huge challenge for practical applications. Herein, we introduce single platinum atom sites coordination with oxygen atom (Pt-O/Pt-O-Fe) sites into single crystalline α-Fe<sub>2</sub>O<sub>3</sub> nanoflakes photoanodes (SAs Pt:Fe<sub>2</sub>O<sub>3</sub>-Ov). The single-atom Pt doping of α-Fe<sub>2</sub>O<sub>3</sub> can induce few electron trapping sites, enhance carrier separation capability, and boost charge transfer lifetime in the bulk structure as well as improve charge carrier injection efficiency at the semiconductor/electrolyte interface. Further introduction of surface oxygen vacancies can suppress charge carrier recombination and promote surface reaction kinetics, especially at low potential. Accordingly, the optimum SAs Pt:Fe<sub>2</sub>O<sub>3</sub>-Ov photoanode exhibits the photoelectrochemical performance of 3.65 and 5.30 mA cm<sup>-2</sup> at 1.23 and 1.5 V<sub>RHE</sub>, respectively, with an applied bias photon-to-current efficiency of 0.68% for the hematite-based photoanodes. This study opens an avenue for designing highly efficient atomic-level engineering on single crystalline semiconductors for feasible photoelectrochemical applications.