Recent advances on three-dimensional ordered macroporous metal oxide-based photoelectrodes for photoelectrochemical water splitting

Abstract

Photoelectrochemical (PEC) water splitting, using semiconductor photoelectrodes to convert solar energy into clean hydrogen energy, is a promising solution to simultaneously address the problems of traditional fossil energy shortage and environmental pollution. In the past decades, substantial research development has been made on metal oxide-based photoelectrodes with ordered structures. Specifically, three-dimensional ordered macroporous (3DOM) structures are advantageous in improving light absorption efficiency through a slow photon effect, multiple-light scattering and anti-reflection, as well as enhancing the charge transport, separation and collection efficiency through a 3D ordered interconnection porous structure. In this review, we first provide a brief introduction to the mechanism and technique for promoting PEC water splitting. Then the benefits of 3DOM photoelectrodes, and effective strategies to improve the overall performances of PEC water splitting are discussed. Subsequently, recent advances in 3DOM metal oxide-based photoelectrodes including TiO₂, ZnO, WO₃, Fe₂O₃, BiVO₄, and Cu₂O are summarized. Insights are also provided on the challenges and future development of ordered macroporous photoelectrodes for PEC water splitting.