Interfacial engineering of S-scheme ZnIn2S4/CoPPc for photoinduced H2 production coupled with benzyl alcohol valorization

Abstract

In response to the inherent problems such as the hysteresis of hole consumption kinetics and the uncontrollable path of oxidation side reactions that are common in the photocatalytic water splitting hydrogen production system, we have innovatively constructed the ZnIn2S4 with Zn vacancy defects/polyphthalocyanine cobalt (VDZIS/CoPPc) stacked S-scheme p-n heterojunction photocatalyst with an interfacial built-in polarization-enhanced electric field through the interface engineering strategy. Remarkably, the synergistic effects of robust interfacial electric field and heterostructure architecture achieve the directional spatial separation and rapid transmission of photogenerated carriers, while retaining the intrinsic strong reduction capacity of CoPPc and the mild oxidation specificity of ZnIn2S4. Additionally, CoPPc contributes photothermal effects and Co-N₄ single-atom active sites, which collectively significantly reduce the activation energy barrier for redox reactions. Consequently, VDZIS/CoPPc enables highly efficient photocatalytic hydrogen production coupled with selective oxidation of benzyl alcohol (BA) to benzaldehyde (BAD). Experiment results demonstrate that the VDZIS/CoPPc exhibits a high hydrogen production rate of 15.22 mmol h-1 g-1, along with 92% BA conversion and 94% BAD selectivity, which surpasses both pristine ZnIn2S4 and previously reported active photocatalysts. This research provides a new strategy for developing integrated photocatalytic system that simultaneously produce hydrogen fuel and enable valuable organic synthesis.