Hematite-based photoanodes for photoelectrochemical water splitting: Performance, understanding, and possibilities

Photoelectrochemical (PEC) water splitting is considered a prospective and attractive way to transforming solar energy to hydrogen (H2). Hematite (α-Fe2O3) is an n-type semiconductor material, having the strength of suitable bandgap, relatively wide light absorption range, high chemical stability, and abundant reserve, which makes it a promising alternative as photoanode material for PEC water splitting. Ever since the earliest research of α-Fe2O3 for PEC water splitting, numerous efforts have been dedicated to developing different strategies for synthesizing and modifying α-Fe2O3 to boost its performance, which has resulted in notable progress in recent years. In this paper, various synthesis methods and modification strategies of α-Fe2O3 in PEC applications are reviewed, principally concentrating on nanostructure design, element doping, co-catalyst modification, heterostructure construction and modification and so forth. In the end, a personal perspective on the challenges and opportunities of this promising material is put forward.