Coupling effects of indium oxide layer on hematite enabling efficient photoelectrochemical water splitting

Hematite (α-Fe2O3) based nanomaterials are considered as the most promising photoelectrodes for solar water splitting. However, some inherent shortcomings like high density of surface states is still the critically challengeable issue. This paper reports the integration of In2O3 nanolayers (NLs) on the surface of worm-like Fe2O3 films to significantly improve the photoelectrochemical (PEC) water oxidation activity. The In2O3 NLs on the modified α-Fe2O3 photoelectrodes exhibit dual positive effects on PEC performance: i) acting as the passivation material to decrease surface electron-hole recombination losses; ii) constructing heterojunctions with Fe2O3 to facilitate efficient separation of surface charges and spatial transfer with extended lifetimes. The resulting treated Fe2O3 photoanode yields a current density of 3.4 mA cm―2 at 1.23 V vs. reversible hydrogen electrode and high incident photon-to-current efficiency of 80 % at 400 nm. These results may bring inspiration to introduce multifunctional modifiers on photoelectrodes that offer practically high-performance PEC applications.