Two-dimensional transition metal-based MOFs for catalytic CO2 reduction and water splitting reactions: Recent insights from first principles calculations

Efficient catalytic CO₂ reduction and water splitting are essential for mitigating greenhouse gas emissions and advancing sustainable energy solutions. However, the design of novel and efficient catalysts faces challenges most of the time due to the inadequate understanding of complex chemical mechanisms and feasible reaction pathways. In several cases, it is hard to construct reasonable catalytic pathways using experimental methods only. Therefore, understanding the detailed mechanisms at the atomistic level requires insights into the fundamental electronic and structural properties, as well as the thermodynamic nature of the catalytic materials used. From quantum mechanical to molecular dynamic scales, theoretical calculations can provide significant and useful information. Recent computational investigations have focused on designing highly efficient catalysts with large surface areas, excellent charge transfer capabilities, high stability, tunable porosity, and a tunable electronic structure. Transition metal-based two-dimensional (2D) organic frameworks (MOFs) can possess these properties and have demonstrated the ability to be used as efficient catalysts for CO₂ reduction reaction (CO₂RR) and water splitting processes. Theoretical calculations play a significant role in promoting our understanding of adsorption mechanisms over MOFs. This review summarizes computational advancements in using transition metal-based 2D MOF materials as novel photocatalysts, focusing on CO₂ reduction and water splitting reactions. The simulation methods, possible structural models, electronic properties, molecular thermodynamics, and reaction mechanisms have been thoroughly discussed. Finally, the challenges and possibilities are highlighted.