Carbon nitride-based Z-scheme photocatalysts for non-sacrificial overall water splitting

Visible-light-driven overall water splitting (OWS) for hydrogen production is a promising strategy for converting solar energy into clean chemical energy. Graphite carbon nitride (GCN) is a promising photocatalyst to drive OWS reaction owing to its suitable band structure, variable structural modulation, visible-light absorption, and chemical stability. Evolving from sacrificial-agent-assisted OWS half-reaction to the non-sacrificial OWS in the past decades, GCN-based Z-scheme structure serves as one of the critical milestones in recent advances of OWS. Through reviewing critical specific examples, this mini-review discusses the configuration, construction approaches, and characteristics of various GCN-based indirect and direct Z-schemes and explains how they regulate the interfacial charge transfer and redox kinetics of GCN to achieve OWS without sacrificing agents. Finally, we propose some existing problems and challenges in the GCN-based Z-scheme system, which may provide some inspirations for future development of efficient photocatalysts for OWS.