Water Splitting and Sustainable NaOCl Generation Using MXene-Supported Ag/Co ₃ O ₄ Nanocomposite

Water splitting technology enables the generation of green hydrogen, simultaneously offering a route for sustainable brine electrolysis to produce sodium hypochlorite (NaOCl). Herein, we report a multifunctional Ag/Co3O4/MXene nanocomposite catalyst active for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) while also facilitating NaOCl production from brine water oxidation. XRD results showed that Ag incorporation reduced the crystallite size of Co3O4, and FTIR analysis confirmed the improved hydrophilicity of the Ag/Co3O4 catalyst resulting from MXene integration. Strong interfacial interactions between MXene and Ag/Co3O4 were established by XPS, leading to oxygen-mediated interfacial bonding and associated charge redistribution, thereby enhancing the catalytic behavior. Electrochemical evaluation demonstrated bifunctional performance, with OER and HER activities comparable to those of RuO2 and Pt/C benchmark catalysts, respectively. Additionally, the catalyst remained stable during extended OER (25 h) and HER (20 h) testing as well as overall water splitting for 30 h at 100 mA cm–2. Importantly, the catalyst achieved the highest reported value of electrochemically synthesized NaOCl yield, 12 g L–1, under optimized conditions, including current density, temperature, electrolysis time, and NaCl concentration (40 mA cm–2, 20 °C, 3–21 h, and 40 g L–1, respectively). These results highlight Ag/Co3O4/MXene as a versatile electrocatalyst for sustainable energy conversion and chemical production.