Iridium-infused Cu-MOF Coupled with S-HfO2 nanoflakes: A Synergistic Heterostructure for Enhanced Photocatalytic Hydrogen Evolution and Pollutant Degradation

Photocatalytic H 2 production and pollutant degradation using solar-driven processes are promising approaches for sustainable energy conversion. However, the reaction efficiency is inadequate due to rapid carrier (e -/ h + ) recombination and poor catalyst stability. In this work, we report a novel heterostructure comprising iridium-modified Cu-MOF coupled with sulfur-doped HfO 2 (S-HfO 2 ), termed as Ir-Cu-MOF/S-HfO 2 composite, to investigate photocatalytic H 2 production and bisphenol-A (BPA) degradation. Advanced characterization studies, such as X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM & TEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and electron spin resonance (ESR), were used to explicate the structural, morphological, electronic, and charge transfer performances of the Ir-Cu-MOF/S-HfO 2 composite. Under LED-light irradiation, the Ir-Cu-MOF/S-HfO 2 photocatalyst displays a H 2 evolution rate of 12.98   mmol   g -1 h -1 using triethanolamine (TEOA) as a sacrificial agent. Simultaneously, it achieves 96% degradation of bisphenol-A (BPA) within 120   min, with a rate constant of 0.018   min -1 , representing superior bifunctional photocatalytic activities. Characteristics studies suggest that the synergistic interaction between Ir-infused Cu-MOF active centres and defect-rich S-HfO 2 facilitates the efficient separation and migration of photogenerated charge carriers. Moreover, the Ir-Cu-MOF/S-HfO 2 photocatalyst exhibits good stability and reusability over prolonged cycles. This study provides valuable insights into the clear design of noble metal-modified MOF-based heterostructures and highlights their potential for integrated solar-driven hydrogen production and environmental pollutant abatement.