Abstract
The direction of renewable energy sources is a natural way to meet the world’s growing energy needs. Converting solar energy into hydrogen through photoelectrochemical (PEC) water splitting is a promising solution. Solar hydrogen production and harvesting require enormous research and practical implementation. In this context, transition metal oxides (TMOs) are of specific interest as photoelectrode materials in addressing these problems. In this perspective, the achieved photocurrent densities and solar-to-hydrogen efficiencies, as well as the suitability of these materials for solar hydrogen evolution, are considered. The main factors limiting the PEC performance and the prospects for the materials are discussed. Based on the state-of-the-art and collected experience, a roadmap for improving performance is proposed.