Enhanced oxygen evolution reaction performance of flower-like CoHS @NCDs through in-situ coupling of Nitrogen-Doped carbon dots and cobalt hydroxide nanosheets

Abstract

Efficient electrocatalytic materials are crucial for enhancing the efficiency of the oxygen evolution reaction (OER) in hydrolysis applications. In this study, we synthesized nitrogen-doped carbon dots (NCDs) via a straightforward one-step hydrothermal method. Subsequently, 3D flower-shaped CoHS@NCDs electrocatalysts were prepared by the integration of NCDs and cobalt hydroxide nanosheets (CoHS) using a solvothermal method. The resulting CoHS@NCDs electrocatalysts demonstrated outstanding catalytic performance for OER under alkaline conditions. Specifically, the CoHS@NCDs-3 electrocatalyst exhibited an overpotential of 280 mV at 10 mA cm⁻²(314 mV at 50 mA cm⁻²), representing an 80 mV improvement compared to CoHS, along with remarkable durability. Through comprehensive characterization, we revealed that the incorporation of NCDs facilitated the creation of numerous exposed active sites on CoHS, forming a unique electron transfer pathway (Co-N), thereby optimizing the kinetics of the OER reaction. This study underscored the significant potential of constructing electrocatalysts with exceptional OER activity based on transition metal hydroxides.