Synthesis and characterization of (Ni, Mn)-ZnO/g-C3N4 nanocomposite for efficient electrochemical water splitting: The role of electrocatalyst for OER

Abstract

The scarcity of non-renewable energy sources and rising worldwide temperatures are significant challenges. Electrochemical water splitting using low-cost materials (metals and their oxides) is a highly efficient and cost-effective method of producing both hydrogen and oxygen. Apart from precious metals, carbon-based materials have also shown effectiveness in catalyzing these reactions. To minimize overpotentials and enable practical applications, metal oxide encapsulation in graphite layers has demonstrated significant activity for both HER and OER. Metal oxides are known for their high conductivity and mechanical strength, making them suitable candidates for this task. In the present research, we report the design of a composite (Ni, Mn)-ZnO/g-C3N4 ((Ni, Mn)-CNZ) electrocatalyst with improved electrocatalytic performance. The coprecipitation of (Ni, Mn)-ZnO with graphitic carbon nitride (g-C3N4) produced the composite material. The structure of the electrocatalyst was analyzed using characteristic techniques such as FTIR, EDX, SEM, and XRD. Electrodeposition on FTO glass is employed to facilitate studies of water distribution. The (Ni, Mn)-CNZ composite exhibits excellent electrochemical water-splitting behavior, with low overpotentials, 380 mV (OER) and 288 mV (HER), reaching a current density of 10 mA cm−2 compared to Ni-CNZ and Mn-CNZ. This highlights the potential of (Ni, Mn)-CNZ as a highly effective electrocatalyst for water splitting.