Scalable synthesis of Co₂C-covered NiTe (Co₂C-NiTe) nanosheets as an efficient electrocatalyst for HER & OER in an alkaline medium

To tackle global carbon conditions, renewable energy-powered electrochemical water splitting is a promising energy conversion device that can enhance the sustainable hydrogen output of the next generation. Regarding large-scale water splitting, novel non-noble metal-based heterostructures focus on constructing highly efficient electrocatalysts with unique interfaces toward hydrogen and oxygen evolution reactions. In this work, to facilitate the limited number of defects in the pure Co₂C and NiTe electrocatalysts, we report that NiTe nanoflakes are coupled with a dispersed nanosheet network of the Co₂C to develop a Co₂C-NiTe composite by interface engineering strategy using a hydrothermal approach. XRD, IV, BET, TEM, XPS, and EDX mapping technologies investigated the 3D structure of as-grown Co₂C-NiTe/SS. Electrochemical test results revealed that our best-performing electrocatalyst delivers a 10 mAcm⁻² with low overpotentials of 279 mV and 227 mV for oxidation and reduction reactions, respectively. Remarkably, this catalyst achieves good stability, reaching up to 90 h in one mol alkaline medium. We showed that this excellent activity of Co₂C-NiTe is primarily due to the abundant interfacial area and stable anchoring sites, which improve the adsorption–desorption energy for hydroxide/oxyhydroxide species and thereby provide a fast electron transfer rate for OER/HER. In addition, a synergistic effect of Co₂C with NiTe presents high electrical conductivity over counterpart electrocatalysts.