Boosted Charge Transfer via Coordinate Bond Construction in Porphyrin Metal–Organic Framework/ZnIn₂S₄ Core–Shell Heterostructures

Intimate interface design at the molecular level in heterojunctions deserves significant attention since the charge transfer efficiency at the interfaces can greatly affect the catalytic performance. Herein, an efficient interface engineering strategy was reported to design a titanium porphyrin metal–organic framework–ZnIn2S4 (TMF–ZIS) core–shell heterojunction which is tightly connected via coordination bonds (−N–Zn−). Such interfacial chemical bonds as the directional carrier transfer channels afforded improved charge separation efficiency compared to the physical composite of TMF and ZIS without chemical bonding. As a result, the optimized TMF–ZIS composite showed a 13.37 mmol·g–1·h–1 H2 production which is 47.7, 3.3, and 2.4 times that of TMF, ZIS, and mechanical mixing samples, respectively. Moreover, the composite also exhibited high photocatalytic tetracycline hydrochloride (TCH) degradation efficiency. Profiting from the core–shell structures, the ZIS shell efficiently prevented the aggregation and photocorrosion of TMF core particles which afforded enhanced chemical stability. Such an interface engineering strategy will be a versatile method to obtain highly effective organic–inorganic heterojunctions and offer new ideas for modulating the interfaces in the heterojunctions at the molecular level.