Activating Co sites activity in Co(OH)₂ via VN coupling to facilitate highly efficient oxygen evolution reaction

The quest for efficient electrocatalysts to drive the oxygen evolution reaction (OER) is paramount for renewable energy technologies such as water electrolysis. This study focuses on augmenting the catalytic activity of cobalt hydroxide (Co(OH)2) electrocatalysts by strategically coupling them with vanadium nitride (VN) heterostructures (Co(OH)2/VN@C). The synergistic effect between Co(OH)2 and VN is explored to achieve a remarkable improvement in the OER performance that the hybrid Co(OH)2/VN@C exhibits a low overpotential of 319 mV at a current density of 10 mA cm-2 and a small Tafel slope of 65 mV dec- 1. Through characterization techniques and electrochemical measurements, we unveil the intricate interplay at the atomic level that triggers the activation of Co sites by V element, leading to an exceptional enhancement in catalytic activity and excellent stability. This work not only sheds light on the fundamental mechanisms involved in the Co(OH)2/VN heterostructure interaction but also presents a promising strategy for designing highly efficient OER electrocatalysts.