Tuning Coordination Chemistry and Composition of Metal–Organic Frameworks for Efficient Hydrogen Production

ABSTRACT Improving the cost and efficiency of hydrogen production via water splitting is a long‐standing research challenge in support of carbon neutrality goals. Optimising the structural composition and coordination chemistry of metal−organic frameworks (MOFs) can yield suitable catalysts or supports that enhance hydrogen production efficiency. MOFs offer precise control over porosity, metal nodes and linker chemistry that is unattainable with conventional catalysts. This review provides a critical, cross‐cutting assessment of MOF‐based catalysis across electrochemical (EC) and photo(electro)chemical (PC and PEC) water‐splitting technologies. We systematically analyse how key structural features (ultrahigh porosity, surface area and compositional changes) and coordination chemistry (tunable metal active sites and functionalised linkers) govern catalytic activity and stability. For electrochemical systems, we critically examine the multifunctionality of pristine MOFs, their conductive carbon‐based derivatives and the synergistic performance of MOF/carbon and MOF/metal hybrids. For MOF‐driven PC and PEC water splitting, we examine MOF selectivity and the mechanisms of light absorption, charge separation and interfacial electron transfer that enable MOFs to serve as integrated platforms bridging light harvesting and redox catalysis. Notably, we devote dedicated sections to limitations in charge‐carrier dynamics and defect engineering, significant bottlenecks that are often overlooked yet key to future performance breakthroughs. A machine‐learning perspective is briefly included, with case studies presented as an emerging design tool for predicting hydrogen adsorption capacity and optimising hydrogen production activity via MOF‐based catalysts. Finally, the review concludes with targeted future directions aimed at accelerating the transition from laboratory discovery to practical, sustainable hydrogen production.