1. Single-atomic-site platinum steers photogenerated charge carrier lifetime of hematite nanoflakes for photoelectrochemical water splitting.
- Author
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Gao, Rui-Ting, Zhang, Jiangwei, Nakajima, Tomohiko, He, Jinlu, Liu, Xianhu, Zhang, Xueyuan, Wang, Lei, and Wu, Limin
- Subjects
PHOTOELECTROCHEMISTRY ,CHARGE carriers ,CHARGE carrier lifetime ,PHOTOCATHODES ,HEMATITE ,SEMICONDUCTORS ,CHARGE transfer ,PLATINUM - Abstract
Although much effort has been devoted to improving photoelectrochemical water splitting of hematite (α-Fe
2 O3 ) 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-Fe2 O3 nanoflakes photoanodes (SAs Pt:Fe2 O3 -Ov). The single-atom Pt doping of α-Fe2 O3 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:Fe2 O3 -Ov photoanode exhibits the photoelectrochemical performance of 3.65 and 5.30 mA cm−2 at 1.23 and 1.5 VRHE , 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. The achievable photocurrent of hematite, α-Fe2 O3 , is typically limited far below its theoretical limit. Here, the authors engineer single Pt atomic sites with surface oxygen vacancies into hematite photoanodes, which leads to enhanced photoelectrochemical water splitting. [ABSTRACT FROM AUTHOR]- Published
- 2023
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