Synthesis of host‐guest hematite photoelectrodes for solar water splitting

Abstract

Hematite (α-Fe2O3) is a promising semiconductor for photoelectrochemical (PEC) water splitting, due to its abundance, low-cost and excellent stability. However, the efficiency of α-Fe2O3 photoelectrodes has been limited by its low hole mobility and fast electron-hole recombination. Host-guest architectures have emerged as a suitable design, which involves the use of a nanostructured collector for high solar absorption while maintaining an ultrathin absorber layer for better charge transport. In this study, a thin mesoporous SiO2 host template coated with a conductive thin layer of TiO2 was optimized to support the α-Fe2O3 film. The α-Fe2O3 thin layer was deposited by spray pyrolysis and then coated with a FeNiOOH co-catalyst. A photocurrent improvement of ca. 85% over planar α-Fe2O3 thin film reference was registered demonstrating the potential of this host-guest approach. (c) 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim