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.

Automated summary

In this study, a three-dimensional and hierarchical Ni-Co-S@NiCo-Cu nanostructure was successfully synthesized and demonstrated outstanding electrocatalytic performance in both hydrogen evolution reaction and urea oxidation reaction.