Low-cost reflux condensation-synthesized nickel cobalt phosphate as an ultra-low overpotential electrode for HER and OER

Recently, there has been a growing focus on creating affordable nanostructured electrode materials with outstanding water-splitting capabilities as a promising replacement for precious metal-based materials. Consequently, designing effective bifunctional electrodes for water splitting presents a significant challenge for researchers working in the energy sector around the globe. With this motivation, in this study, we report a facile and efficient synthesis of nickel cobalt phosphate on flexible stainless steel mesh (NCP@FSSM), employing a reflux condensation deposition technique. The as-synthesized electrode delivers ultra-low overpotentials of 230 mV and 101 mV at 10 mA cm⁻² for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively, positioning it as a high-performance candidate for overall water splitting. Moreover, long-term durability tests reveal robust operational stability with the NCP@FSSM electrode maintaining performance over 80 h for OER and 50 h for HER, meeting a key requirement for commercial viability. The superior electrochemical characteristics of the NCP@FSSM electrode are attributed to its low overpotential, high electrochemical surface area (ECSA), high turnover frequency (TOF) number, good faradic efficiency, and elevated mass activity, which drives efficient electrocatalysis. Additionally, the unique binder-free nanorod architecture ensures a dense distribution of active sites and a synergistic interaction among nickel, cobalt, and phosphorus, optimizing both HER and OER performance. The abovementioned results designate that the NCP@FSSM electrode is a promising bifunctional electrode for the water-splitting application.