Recent advances on MOF ligand engineering for CO2 hydrogenation

Catalytic hydrogenation of CO 2 to value-added chemicals, including carbon monoxide (CO), methane (CH 4 ), methanol (CH 3 OH), and C 2+ hydrocarbons/oxygenates, represents a pivotal strategy for mitigating carbon emissions and advancing a circular carbon economy. Metal-organic frameworks (MOFs) have emerged as highly promising platforms for CO 2 hydrogenation because ligand engineering enables precise control over active sites, electronic structure and nanoconfined environments. Strategically modifying ligands permit atom-level modulation of the electronic structure of metal nodes, precise tuning of pore geometry and functionality, and the fabrication of synergistic, multifunctional active sites, thereby directing the activation of CO 2 and H 2 , stabilization of key intermediates ( e.g. , ⁎ HCOO, ⁎ CO, ⁎ CH x ), and ultimately steering of reaction pathways toward target products. This review provides a comprehensive and in-depth analysis of ligand-engineering strategies for MOF-based CO 2 hydrogenation. We systematically summarize the synthetic methodologies for ligand-modified MOFs, delve into the fundamental mechanisms by which ligand engineering modulates catalytic properties ( e.g. , electronic effects, confinement, and cooperativity), and detail its application in controlling selectivity toward CO ( via reverse water gas shift), CH 4 ( via methanation), CH 3 OH ( via the formate pathway), and more complex C 2+ products. Our analysis highlights the unique advantages and structure-performance relationships conferred by MOF architecture and ligand engineering while addressing prevailing research bottlenecks, such as stability under process conditions and scalability. Finally, we outline persistent challenges and propose forward-looking research perspectives, including the development of dynamic ligands, machine-learning-assisted rational design, and process intensification strategies. This review aims to elucidate the transformative impact of ligand engineering in advancing MOF-based CO 2 hydrogenation catalysis. It serves as a comprehensive framework for understanding how precise ligand modulation can dictate reaction pathways. By establishing structure-performance relationships and identifying key frontiers such as dynamic stimuli-responsive systems and rational stability engineering, this review aims to inspire the design of next generation catalysts.