Bridging the g-C₃N₄ Nanosheets and Robust CuS Cocatalysts by Metallic Acetylene Black Interface Mediators for Active and Durable Photocatalytic H₂ Production

It is still a grand challenge to effectively increase both the active sites and charge separation of earth-abundant semiconductors for efficient and durable photocatalytic hydrogen evolution. To achieve these aims, we design acetylene black (AB) as the electron bridge that links the g-C3N4 (CN) nanosheeets and robust copper sulfide (CuS) cocatalysts for photocatalytic hydrogen evolution though sonochemical loading and followed chemical precipitation methods. It was revealed that AB nanoparticles as the oriented electron-transfer pathways could effectively improve the separation/collection of photoexcited electrons and the stability of CuS, whereas the CuS cocatalysts as active sites could dominantly boost the surface H2 evolution. Both of the CuS and AB could enhance the light absorption of the pure CN, which is favorable for improving the photocatalytic H2 production of CN. As a result, the ternary CN-0.5%AB-2%CuS photocatalyst displays a robust hydrogen evolution rate of 348 μmol h–1 g–1, which is 348 and 1.5 times as high as those of pure CN (1 μmol h–1 g–1) and CN-1%Pt (230 μmol h–1 g–1), respectively. More importantly, compared with the binary CN-CuS sample, the ternary robust CN-AB-CuS photocatalyst showed remarkable stability, which could be applied repeatedly with little loss of photocatalytic performance after 15 cycles. It is anticipated that this study could inspire some new ideas for rational design and construction of the highly stable and active photocatalytic H2-evolution systems through earth-abundant nanocarbons and cocatalysts.