Water-soluble Peroxotitanium Complex: A Novel Strategy to Prepare Fe2O3/Fe2TiO5 Photoanode with Enhanced Water Oxidation

ABSTRACT The construction of Fe2O3/Fe2TiO5 heterostructure has been proven as an effective strategy to improve the photoconversion efficiency of hematite, however its controllable synthesis is still a great challenge. In this study, by performing a comparative investigation on two distinct Ti precursors, a novel, convenient, and low-cost approach for fabricating efficient Fe2O3/Fe2TiO5 photoanodes is developed. It clearly demonstrates that the adoption of typical TiCl4 precursor leads to a Fe2O3/TiO2 composite with a lower PEC activity, while a core-shell Fe2O3/Fe2TiO5 heterostructure is built via using the stable and water-soluble peroxo-titanium complex (PTC) precursor. The as-fabricated photoanode exhibits a comparable photocurrent density of 2.51 mA/cm2 at 1.23 V vs. RHE to most of Fe2O3/Fe2TiO5 photoanodes in literatures. Based on various characterizations, the significant enhancement in PEC performance can be attributed to the largely increased donor density and the formation of Fe2O3/Fe2TiO5 core-shell heterostructure, which effectively facilitate the charge separation and transport in the bulk and surface of photoanode. This work provides a new idea for fabricating high-efficient Fe2O3/Fe2TiO5 photoanodes.