Accelerating the Energy-Saving Electrochemical Hydrogen Production by Electrodeposited Ultrathin 3-D Ni-Co-S Nanosheets on Ni-Co-Cu Nano-Micro-dendrites

Substituting the OER process with a more thermodynamically favorable process, like the urea oxidation reaction (UOR), leads to energy-saving hydrogen production. Here, the three-dimensional and hierarchical Ni-Co-S@NiCo-Cu nanostructure was successfully synthesized and its electrocatalytic behavior was investigated. Investigations of the electrocatalytic behavior showed the unique performance of the Ni-Co-S@Ni-Co-Cu electrode, where in optimized conditions, in the HER process, to achieve 10 mA.cm 2 current density, the overpotential value was 68 mV. Also, when the Ni-Co-S@Ni-Co-Cu electrode was employed in both in HER and UOR processes simultaneously, to achieve the 10 mA.cm 2 current density, 1.38 V was needed. Also, the results of electrocatalytic stability represented insignificant changes in voltage over long periods (100 mA.cm 2, 50 h). The reason for such outstanding electrochemical performance in activity and stability point of view, was the synergistic effect between elements, large active surface area, using a binder-free method, and the regular hierarchical structure.