Single-atomic-site platinum steers photogenerated charge carrier lifetime of hematite nanoflakes for photoelectrochemical water splitting

Rui-Ting Gao; Jiangwei Zhang; Tomohiko Nakajima; Jinlu He; Xianhu Liu; Xueyuan Zhang; Lei Wang; Limin Wu

doi:10.1038/s41467-023-38343-6

Single-atomic-site platinum steers photogenerated charge carrier lifetime of hematite nanoflakes for photoelectrochemical water splitting

Nat Commun. 2023 May 8;14(1):2640. doi: 10.1038/s41467-023-38343-6.

Authors

Rui-Ting Gao¹, Jiangwei Zhang¹, Tomohiko Nakajima², Jinlu He³, Xianhu Liu⁴, Xueyuan Zhang⁵, Lei Wang⁶, Limin Wu^{7

8}

Affiliations

¹ College of Chemistry and Chemical Engineering, College of Energy Material and Chemistry, Inner Mongolia University, Hohhot, 010021, China.
² Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan.
³ College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot, 010021, China. hejinlu@imu.edu.cn.
⁴ Key Laboratory of Materials Processing and Mold, Ministry of Education, Zhengzhou University, Zhengzhou, 450002, China.
⁵ State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China.
⁶ College of Chemistry and Chemical Engineering, College of Energy Material and Chemistry, Inner Mongolia University, Hohhot, 010021, China. wanglei@imu.edu.cn.
⁷ College of Chemistry and Chemical Engineering, College of Energy Material and Chemistry, Inner Mongolia University, Hohhot, 010021, China. wlm@imu.edu.cn.
⁸ Department of Materials Science and State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai, 200433, China. wlm@imu.edu.cn.

Abstract

Although much effort has been devoted to improving photoelectrochemical water splitting of hematite (α-Fe₂O₃) 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-Fe₂O₃ nanoflakes photoanodes (SAs Pt:Fe₂O₃-Ov). The single-atom Pt doping of α-Fe₂O₃ 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:Fe₂O₃-Ov photoanode exhibits the photoelectrochemical performance of 3.65 and 5.30 mA cm^-2 at 1.23 and 1.5 V_RHE, 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.