Rational design of a low-cost, simple technology and high-performance CoNi/Co3O4 as a catalyst in sodium borohydride electro-oxidation reaction

Abstract

To improve the complexity and low catalytic performance and reduce the high cost of the traditional electrode preparation process for the sodium borohydride electro-oxidation reaction (BOR), in this work, a self-supported and efficient electrode material grown on nickel foam (CoNi/Co₃O₄/NF) was successfully designed using a simple hydrothermal synthesis method accompanied by the electrodeposition process. Benefiting from the three-dimensional nanoarray structure of CoNi/Co₃O₄/NF and the uniform distribution of Co and Ni modulating active sites by electrodeposition, the catalytic activity towards NaBH₄ exhibits high efficiency. CoNi/Co₃O₄ exhibits excellent catalytic performance (up to 2157 mA cm⁻² in 2 mol L⁻¹ NaOH and 0.3 mol L⁻¹ NaBH₄), a high electrochemically active surface area (62.5 cm⁻²), and a low activation energy (15.56 kJ mol⁻¹). The CoNi/Co₃O₄/NF electrode was further investigated on a direct sodium borohydride–hydrogen peroxide fuel cell (DBHPFC), which exhibited a maximum power density of 108.5 mW cm⁻² and excellent stability. The excellent performance is mainly due to its unique nanoarray structure and electrodeposition distribution of Co and Ni active sites, which increases the electrochemical surface area and enhances the contact between the electrode and the electrolyte.