Performance of WO3/g-C3N4 heterojunction composite boosting with NiS for photocatalytic hydrogen evolution

Carbon nitride, which is an intriguing photocatalyst but subjected to low surface area and rapid charge recombination, is used to produce H-2 under the condition of visible-light. Here, we came up with a straightforward efficient approach to boost the hydrogen production performance of g-C3N4 for the first time, namely, the H-2 production performance of the NiS/WO3/g-C3N4 synthetic was greatly enhanced approximately 8.9 multiples higher than that of pristine g-C3N4. The electronic structure and carrier behaviors of g-C3N4 are modified by a strategy of in-situ growth of NiS-WO3 assisted by NiS. The NiS-assisted WO3/g-C3N4 heterojunction system provides more active sites for the formation of heterojunction system which could promote charge separate and transfer efficiently. The photocatalytic hydrogen production rate of NiS which was used as a cocatalyst, was greatly increased in the hydrogen evolution reaction when added photocatalyst into the system, reaching 2929.1 mu mol g(-1) h(-1) below the radiation of optical light. The improvement of photocatalytic performance can be owed to two aspects. First of all, the heterojunction formed by WO3/g-C3N4 can efficiently suppress the recombination of photogenerated electrons and holes. In addition, the presentation of NiS improves the electron mobility rate and provides more active sites for hydrogen evolution, which are proved with a succession of studies like XRD, FT-IR, TEM, SEM, BET, UV-vis DRS, XPS, photoelectric performance test and steady state/transient fluorescence. This work provides a hopeful approach for improving the property of g-C3N4 from the perspective of electronic structure and carrier behavioral regulation. At the same time, it provides new insights for hydrogen evolution of g-C3N4 heterojunction composites.