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

Although much effort has been devoted to improving photoelectrochemical water splitting of hematite (α-Fe(2)O(3)) 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(2)O(3) nanoflakes photoanodes (SAs Pt:Fe(2)O(3)-Ov). The single-atom Pt doping of α-Fe(2)O(3) 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(2)O(3)-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.