Enhanced electrocatalytic performance of LCO-NiFe-C₃N₄ composite material for highly efficient overall water splitting

The rising global energy demand & environmental crisis spur exploration of traditional fuel alternatives. Hydrogen, with high energy density & pollution-free potential, is seen as a promising energy carrier. The development of efficient and durable electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is of paramount importance for renewable energy conversion and storage systems. Developing efficient and stable catalysts is crucial for improving OER performance, but the scarcity, high cost, and stability issues of precious metal oxide catalysts hinder their industrial application. Herein, the composite material was synthesized using a combination of sol-gel and one-step hydrothermal methods, followed by an annealing process. The inherent electrocatalytic activity of LaCoO₃, a perovskite oxide, towards both OER and HER was harnessed. In an alkaline electrolyte, the LCO-NiFe-C₃N₄ demonstrated remarkable electrocatalytic performance with overpotentials of 251.4 mV for OER and 186.7 mV for HER at a current density of 10 mA cm-2. The Tafel slopes were 60.8 mV dec-1 for OER and 138.53 mV dec-1 for HER, suggesting that the LCO-NiFe-C₃N₄ composite material is a promising candidate as a bifunctional catalyst. Theoretical calculations also confirm that doped elements can effectively regulate the electronic properties of active sites, thereby reducing the energy barrier of the rate-limiting step in the OER reaction and significantly enhancing the electrocatalytic activity of the catalyst. This study presents the synthesis and electrocatalytic performance evaluation of a novel (LCoO₃-NiFe-C₃N₄) LCO-NiFe-C₃N₄ composite material, showcasing its potential as an effective bifunctional catalyst.