Enhanced photocatalytic overall water splitting via non-precious Zn-induced spatial separation of photoexcited excitons in polymeric carbon nitride

• Published in: Fuel (Guildford) 2025-02, Vol.381, p.133473, Article 133473
• Main Authors: Jin, Zhengyuan, Xu, Yangsen, Xue, Bin, Zhang, Luhong, Wang, Xinzhong, Arif, Nayab, Ahsan Iqbal, Muhammad, Qi, Lu, Zeng, Yu-Jia, Ohno, Teruhisa
• Format: Article
• Language: English
• Subjects: Co-catalyst; Overall water splitting; Photocatalysis; Polymeric carbon nitride; Spatial separation
• ISSN: 0016-2361
• DOI: 10.1016/j.fuel.2024.133473

Inserting Zn between TCN and PtO forms a ladder structure co-catalyst, which spatially separates photoexcited electron-hole pairs and inhibits back reaction. After the depositing of a Cr2O3 layer on PtO and the addition of an oxidation co-catalyst, CoOx, this co-catalyst strategy significantly enhances the hydrogen and oxygen evolution rate of CN in OWS. [Display omitted] •Ultra-thin carbon nitride synthesized via a one-step calcination method.•A co-catalyst strategy for enhancing overall water splitting.•Zn between the photocatalyst and PtO spatially separates electron-hole pairs.•Coating of Cr2O3 on PtO to suppress the recombination of H2 and O2. Photocatalytic water splitting has emerged as a vital technology for producing clean hydrogen fuel, addressing global energy needs. However, most research has focused on half-water splitting with sacrificial agents, which limits its practical application in fuel production. In this study, we present an advanced co-catalyst system for polymeric carbon nitride (CN) designed for efficient overall water splitting, a crucial step toward scalable hydrogen fuel generation. The co-catalyst system includes full loading of CoOx, Zn-Pt, and Cr2O3, with Zn strategically inserted between Pt and CN. This configuration enhances the spatial separation of photoexcited carriers, promoting efficient segregation of oxidation and reduction sites while minimizing electron-hole recombination. The optimized system achieves a stoichiometric H2 and O2 ratio of 2:1, with a hydrogen evolution rate that is nine times higher than when Pt alone is used as the co-catalyst. This advancement provides a pathway for efficient solar-driven hydrogen production, addressing the critical challenge of moving beyond half-water splitting and contributing to the development of clean fuel technologies.