Comparison of oxygen evolution reaction performance for Ni and Co using isostructural trans-cinnamate complexes

Efforts are underway to develop highly active catalysts to reduce the high overpotential of the oxygen evolution reaction (OER). Metal–organic frameworks or coordination polymers are promising candidates because of their tunable structures and high surface areas. In this study, Nickel and Cobalt trans-cinnamate (t-ca) were synthesized via a hydrothermal method. Their structures were analyzed and found to be isostructural. Both complexes exhibited superior electrocatalytic properties in the OER compared to those of IrO₂, with overpotentials of 373 and 390 mV and Tafel slopes of 58 and 66 mV/dec. These excellent characteristics were attributed to the electron delocalization of the metal centers via interactions with π-π delocalized organic ligands. Ni t-ca, with stronger ligand interactions, displayed an enhanced OER catalytic performance, emphasizing the importance of metal–ligand interactions and suggesting that further exploration of diverse π–π delocalized organic ligands and metal centers may lead to further advancements in electrocatalytic activity.