Nickel porphyrin/ZnIn2S4 heterojunction with Ni-S highway for boosting charge separation and visible-light-driven H2 production

Due to the exceptional potential to retard the charge recombination, semiconductor-based heterojunctions as photocatalysts have attracted extensive attention. Herein, nickel(II) 5,10,15,20-tetraphenyl-21H,23H-porphyrin (NiTPP) and ZnIn2S4 (ZIS) floriated microspheres are used to construct a novel inorganic-organic heterojunction (NiTPP/ZIS). Compared with the NiTPP and ZIS, the resultant NiTPP/ZIS exhibits enhanced optical absorption, charge separation and photoelectrochemical behavior. Further investigations demonstrate that a type II heterojunction mechanism proceeds in the NiTPP/ZIS heterojunction to boost the charge separation via the Ni-S highway formed between the NiTPP and ZIS components. No need of additional cocatalyst, the NiTPP/ZIS heterojunction with an optimal mass ratio delivers a superior apparent quantum yield of 64.0% at 400 nm and a remarkable H2 evolution activity of 2305 μmol h-1 under visible light (λ ≥ 400 nm) irradiation, 10 and 256 times higher than that of the ZIS and NiTPP alone, respectively. This work presents a new concept for constructing inorganic-organic heterojunctions for high-performance artificial photosynthesis systems.