High-crystalline/amorphous g-C3N4 S-scheme homojunction for boosted photocatalytic H2 production in water/simulated seawater: Interfacial charge transfer and mechanism insight

Photocatalytic water and seawater splitting into H2 is a promising strategy to attract the attention of researchers due to unique advantages including environment-friendly, cost-effectiveness and strong applicability. In this work, the high-crystalline/amorphous g-C3N4 (HCCN/ACN) S-scheme homojunctions are fabricated by solvothermal method and applied in photocatalytic H2 production no matter in water or seawater environments. The results of characterizations and experiments confirm that HCCN/ACN-6:4 S-scheme homojunction possesses optimal photocatalytic H2 evolution rate in water (5.534 mmol h−1 g−1) and seawater (3.147 mmol h−1 g−1) respectively, which is ascribed to the following reasons: (i) the accelerated interface charge transfer in distinctive S-scheme homojunction could produce more active groups to participate in photocatalytic reaction; (ii) the improved specific surface area in HCCN/ACN-6:4 can provide more active sites on the surface to promote photocatalytic H2 production; (iii) enhanced hydrophilic in HCCN with abundant photo-reaction reduced sites is beneficial to photocatalytic H2 evolution reaction between electrons and water molecules. This work provides a novel prospect for designing S-scheme homojunction photocatalyst with outstanding photocatalytic performance.