Defect-Rich Co(OH)2 Induced by Carbon Dots for Oxygen Evolution Reaction

Hydrogen production from water electrolysis offers a highly promising and sustainable route to solve the energy crisis. However, it is severely limited by the sluggish kinetics of the oxygen evolution reaction (OER) occurring on the anode. Herein, employing carbon dots functionalized with benzene sulfonate groups (BS-CDs) as a distinctive inductor, a Co(OH)2 catalyst featuring abundant defects was synthesized for an enhanced OER. The highly hydrophilic nature of BS-CDs exerts a significant interfacial induction effect on the growth dynamics of Co(OH)2, fostering the formation of elevated crystal defects and a substantial quantity of oxygen vacancies. The resulting BS-CDs/Co(OH)2 catalyst requires an overpotential of only 340 mV to achieve a current density of 10 mA cm−2 in alkaline media, demonstrating markedly improved OER activity compared to pristine Co(OH)2 and N-CDs/Co(OH)2 induced by amine-modified CDs. Furthermore, the structural integrity of the catalyst is maintained, with a current retention rate of 92% observed following a 20 h stability assessment. This work provides a novel approach for developing cost-effective transition metal catalysts that exhibit exceptional catalytic efficiency and excellent stability for the OER.