Innovative Photocatalyst Design: Advancing ZnO/MIL‐100(Fe) through Atomic Layer Deposition in Hydrogen Evolution

Abstract

This study investigates the integration of ZnO nanoparticles into the MIL‐100(Fe) framework using atomic layer deposition (ALD) at atmospheric pressure, varying ALD cycles from 0.5 to 2. The goal is to enhance the photocatalytic efficiency of MIL‐100(Fe) in water splitting under ultraviolet light. Among the composites, the ZnO/MIL‐100(Fe) synthesized with a 1‐cycle ALD process stands out, demonstrating superior hydrogen evolution rates (8465 μmol·g⁻¹·h⁻¹) and improved durability, surpassing the base MIL‐100(Fe) in repeated PWS trials. Comprehensive characterization using various analytical techniques, including BET analysis, DRS, EDS, SEM, TEM, XRD, FT‐IR, Raman, and PL, sheds light on the structural, chemical, and optical properties of the MIL‐100(Fe)/ZnO materials, confirming successful ZnO deposition within the MIL‐100(Fe) structure. Furthermore, the enhancement in photocatalytic activity is associated with increased absorption intensity and reduced trap sites, implying improved charge carrier dynamics and separation. The inclusion of ZnO not only reduced the bandgap of composites, but also influences the photoluminescence characteristics significantly, leading to a reduction in non‐radiative recombination and enhancing the availability of photogenerated electrons for photocatalytic reactions. Specifically, the increased photoluminescence intensity observed with ZnO/MIL‐100(Fe) composites indicates a higher defect density, which corresponds to more active sites for photocatalysis.