Effects of Nitrogen-Doped Carbon Support on the Electrocatalytic Behavior of Co Nanoparticles for Oxygen Evolution Reaction in Neutral Media

Proton exchange membrane-based water electrolysis (PEM-WE) offers significant benefits over traditional alkaline water electrolysis and has become a highly potential approach for generating hydrogen. To enable efficient PEM-WE in neutral media, the activity of cobalt (Co)-based materials for the oxygen evolution reaction (OER) has been considerably improved by tuning the electronic configuration. Nevertheless, electrocatalyst-substrate interactions and the role of supports in OER performance have not been thoroughly investigated. Herein, we looked into how a porous nitrogen-doped carbon (NC) support affected the electrocatalytic performance of small cobalt nanoparticles (Co NPs) for OER in a neutral environment. A series of experiments and density functional theory (DFT) calculations indicated that the strong coupling of Co NPs and NC support contributed to the coordination of Co with graphitic N, which in turn resulted in modulating the local electron structure around the Co atom center and diminishing the energy barriers for intermediates and the change in Gibbs free energy for the rate-limiting step. The OER activity of optimal Co NPs anchored on porous NC support (Co/NC) was significantly elevated, delivering an overpotential of merely 418 mV at 10 mA cm^-2 and a favorable Tafel slope of 136 mV dec^-1 in neutral 1 M phosphate-buffered saline (PBS) containing 0.5 M NaCl, as well as exhibiting long-term stability. This remarkable OER-catalyzing ability outperformed the majority of previously reported transition metal-based electrocatalysts. This study provides a universal and scalable method for adjusting catalyst-support interactions for electrocatalytic reactions and other processes.