Development of a Durable and Robust Co₃O₄@Carbon Dot Heterostructure Electrocatalyst for Clean Hydrogen Production

The search for clean, sustainable, and highly efficient energy sources is critically important to meet the requirements of the modern world. In this regard, water electrocatalysis is being adopted as one of the cutting-edge technologies. Numerous novel electrocatalysts have been developed to improve the efficiencies of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). In the present work, we report a newly designed electrode based on Co3O4@carbon dots (CDs), which exhibits excellent catalytic activity and long-term stability toward water splitting in an alkaline environment. The fabricated Co3O4@CDs electrode shows a low overpotential of 326 mV for the OER and Tafel slope of 70 mV dec–1 at 10 mA cm–2 compared to IrO2 (overpotential = 350 mV and Tafel slope = 34 mV dec–1). The nanocomposite shows steady growth of the HER, with a Tafel slope of 115 mV dec–1, an overpotential of 165 mV at 10 mA cm–2, and stability for up to 60 h for the HER. This enhanced catalytic activity is attributed to its enlarged electrochemical active surface area (ECSA), which is one of the key elements required for higher efficiency. Moreover, various physical and electrochemical approaches have been used to study the Co3O4@CD materials and investigate the relationship between their characteristics and activity. As a result, our findings not only support the use of carbon dots in electrochemical hydrogen production but are also useful as a practical alternative for future applications.