Homojunction photocatalysts for water splitting

Charge-carrier separation is regarded as one of the critical issues of photocatalytic water splitting and could be accelerated by constructing microscopic junctions in photocatalysts. Homojunction photocatalysts consisting of different forms of semiconductor with identical compositions could inherit the advantages of heterojunction-based photocatalysts in charge separation due to the built-in electric field, while omitting the potential drawbacks of interfacial lattice distortion by providing continuous band bonding. Therefore, homojunction-based photocatalysts have recently drawn growing attention in water splitting. In this review, the synthetic approaches to preparing photocatalysts with various homojunction structures including p-n junction, phase junction, and facet junction were introduced, together with a comprehensive analysis and discussion on the latest progress in the application of photocatalytic water splitting. This review work is expected to inspire more related work with promoted research on designing efficient homojunction-based photocatalytic systems for water splitting.