Synthesis of Co0·52Cu0·48/Cu@S–C arrays for the enhanced performance of hydrazine-assisted hydrogen production

The development of efficient bifunctional catalysts is the key technology to replace oxygen evolution reaction (OER) with hydrazine oxidation reaction (HzOR) with lower theoretical potential to achieve high efficiency and energy-saving hydrogen production . In this work, the Co 0·52 Cu 0·48 /Cu@S–C (−1.3 V) composite with flower-like array was prepared by two-step electrodeposition coupled pyrolysis method. The electrochemical measurements showed that the driving voltages of the optimal composite for HzOR and hydrogen evolution reaction (HER) are respectively −118 mV and 47 mV at a current density (j) of 10 mA cm −2 . The excellent performance of Co 0·52 Cu 0·48 /Cu@S–C (−1.3 V) composite is attributed to the fact that the flower-like structure exposes more active areas and facilitates the diffusion of electrolyte, the strong electron interaction between Co 0·52 Cu 0·48 /Cu and S –C substrate, which can be verified by X-ray photoelectron spectroscopy (XPS), enhances the electrical conductivity , the Co 0·52 Cu 0·48 /Cu heterogeneous interface reduces the water dissociation barrier and facilitates the dehydrogenation kinetics of N 2 H 4 determined by density functional theory (DFT) calculations. Due to the excellent performance of Co 0·52 Cu 0·48 /Cu@S–C (−1.3 V), the overall hydrazine splitting (OHzS) electrolytic cell was constructed with Co 0·52 Cu 0·48 /Cu@S–C (−1.3 V) as electrodes. The results showed the voltages required by the cell are 36, 210 and 282 mV at the current density values of 10, 100 and 200 mA cm −2 respectively, showing that Co 0·52 Cu 0·48 /Cu@S–C (−1.3 V) can be used for energy-saving hydrogen production by hydrazine assisted water electrolysis.