Self-reduced CuₓO multichannels at TiO₂/porphyrin metal-organic frameworks interface for enhanced photocatalytic...

The construction of efficient interfacial charge transfer channels is crucial for enhancing the photocatalytic performance of hybrid materials but remains challenging. Herein, a novel TiO₂/metalloporphyrin indium-based metal-organic framework (CuInMOF) nanohybrid (denoted as TiO₂-Cu-CuInMOF) was easily constructed via a one-pot solvothermal method. Innovatively, self-reduced copper species (primarily Cu₂O) were generated in situ and served as multichannel bridges between TiO₂ and CuInMOF, utilizing the intrinsic reducing groups of the TiO₂ precursor without the need for external reductants. The optimized TiO₂-Cu-CuInMOF nanohybrid exhibited a remarkable photocatalytic H₂ evolution rate of 35.06 mmol·g^-1, which is 39, 34.7, and 2.6 times higher than those of pristine TiO₂, CuInMOF, and the controlled without copper bridges (TiO₂-CuInMOF), respectively. A combination of in situ X-ray photoelectron spectroscopy (XPS), surface photovoltage spectroscopy, photoelectrochemical tests, and finite-difference time-domain simulations (FDTD) confirmed that the copper bridges significantly accelerated interfacial charge separation and transfer. Furthermore, in situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations revealed that the N sites of the porphyrin macrocycle and the In sites acted as active centers for H₂ evolution. This work provides a novel strategy for designing highly efficient photocatalysts by engineering internal electron transfer pathways based on the intrinsic properties of the components.