Carbon Nanofiber-Integrated CuCo-MOF as a Conductive Bifunctional Electrocatalyst for Overall Water Splitting

Abstract The CuCo-MOF/CNF electrocatalyst, with a well-defined microstructure and efficient charge transfer was successfully synthesized through a simple solvothermal method. In the CuCo-MOF/CNF composite, the introduction of CNF can effectively improve the conductivity and provide sufficient active sites for the electrochemical reaction. The CuCo-MOF/CNF composite has excellent bifunctional electrocatalytic activity for the HER and OER reactions. The catalyst really stands out with its great performance, requiring overpotentials of 50 mV for HER and 70 mV for OER at a current density of 10 mA cm–2. The CuCo-MOF/CNF electrocatalyst has low Tafel slope values of 98 mV dec–1 for OER and 131 mV dec–1 for HER, along with low charge transfer resistance, exhibiting excellent operational stability for up to 40 h for both OER and HER. Moreover, the catalyst has relatively large double-layer capacitance values of 8.95 mF cm–2 for OER and 3.47 mF cm–2 for HER, implying that the electrochemically active surface areas are quite large (223.8 cm2 for OER and 86.8 cm2 for HER). Overall, these structural and electrochemical advantages contribute to the superior catalytic performance of the electrocatalyst, providing a novel framework for the development of highly efficient and scalable bifunctional electrocatalysts for overall water splitting.