Unlocking high-efficiency oxygen evolution reaction through Co-N coordination engineering in Co@N-doped porous carbon core–shell nanoparticles

Modulation of metal sites coordination can significantly refine the electronic architecture of catalysts, thereby improving their catalytic performance. This work successfully developed a core–shell Co@N-doped porous carbon (Co@NC) catalyst by pyrolyzing the COF/MOF (IISERP-COF3/ZIF-67) composite in an inert atmosphere. The Co@NC catalyst exhibited impressive oxygen evolution reaction (OER) performance, with a small overpotential of 304 mV and a modest Tafel slope of 88.6 mV·dec⁻¹ in a 1 M KOH, alongside remarkable stability, maintaining 98.5% of its activity over 13 h. The role of IISERP-COF3 was pivotal in preventing Co atom aggregation during the ZIF-67 pyrolysis, which facilitated the creation of mesopores for enhanced mass transport and conductivity. Moreover, it effectively modulated the Co-N coordination to fine-tune the electronic structure, thereby optimizing the catalyst's capacity for adsorption of intermediates and boosting its intrinsic activity. Density functional theory (DFT) studies corroborate that the exceptional OER efficiency of Co@NC can be linked to the enhanced Co-N coordination, optimizing the localized electronic structure at the Co active sites. This study not only proposes an innovative approach for optimizing COF/MOF as effective electrocatalysts but also clears the path for the emergence of affordable, high-performance alternatives to precious metal-based catalysts, marking a significant advancement in sustainable energy technologies.