Tailoring 2D metal-organic frameworks for enhanced CO2 reduction efficiency through modulating conjugated ligands

The technology of electrocatalytic reduction of CO2 to produce hydrocarbon fuels not only alleviates energy shortages but also suppresses the greenhouse effect, demonstrating enormous potential applications. In this context, we aim to explore new reliable materials for reducing CO2 (CO2RR) through electrocatalysis. Hence, we investigated the performance of Cu3(C12X)2, where X signifies organic-ligands (N₁₂H₆, N₉H₃O₃, N₉H₃S₃, N₆O₆, N₆S₆) for the CO2RR using density functional theory (DFT). The 2D Cu3(C12X)2 monolayers show metallic characteristics because of the presence of adequate π electron conjugation network as-well-as a constructive interaction between the metal atom, organic-ligands, and benzene-rings, with the exception of Cu3(C12N9H3O3)2, which displayed semiconducting characteristic. The catalytic activity of Cu3(C12X)2 can be tuned by adjusting the organic-ligands' ability to facilitate interaction between the CO2RR intermediates and the metal complex (Cu-X4). Among all MOFs, Cu3(C12N6S6)2 have excellent CO2RR activity towards CO and formic acid. All other Cu3(C12X)2 monolayers demonstrated dynamic CO2RR catalytic activity as well as superior selectivity over hydrogen evolution (HER) suggesting that these materials have the potential to be useful as CO2RR electrocatalysts. This study introduces the concept of building MOFs with favorable features to meet the specific needs of a number of research domains including catalysis, energy conversion and storage. [Display omitted] •The 2D Cu3(C12X)2 MOFs monolayers showed metallic behavior with good conductivity for electron transfer.•The optimized lattice parameters and the pore size of Cu3(C12X)2 fluctuate via changing the organic ligands.•Cu3(C12X)2 monolayers exhibit single-atom catalyst features with a metal atom distance ≥10.65 Å.•Cu3(C12X)2's CO2 reduction performance is contingent on robust Cu-X4 complex interactions with intermediates.•Cu3(C12N6S6)2 demonstrates remarkable CO2RR to CO and formic acid activity.