Enhanced Photocatalytic Efficiency Through Oxygen Vacancy‐Driven Molecular Epitaxial Growth of Metal–Organic Frameworks on BiVO 4

/MIL-101-Si solar cell system, achieving a solar-to-hydrogen efficiency of 4.33%. The molecular-level integration mitigates surface states and enhances the internal electric field, facilitating the migration of photogenerated holes into the MIL-101 overlayer. This process activates highly efficient Fe catalytic sites, which effectively adsorb water molecules, lowering the energy barrier for water oxidation and improving interfacial kinetics. Further studies confirm the broad applicability of oxygen vacancy-induced molecular epitaxial growth in various MOFs, offering valuable insights into defect engineering for optimizing interfaces and enhancing photocatalytic activity.