Nickel-cobalt derived nanowires/nanosheets as electrocatalyst for efficient H2 generation via urea oxidation reaction

• The same precursors were used for synthesizing oxides and phosphides, respectively. • Ni 2 Co 1 -P/CC with the morphology of nanosheets exposed more active sites toward HER. • The effects of Ni-Co ratio in Ni x Co 3−x -O/CC toward UOR catalytic performance were invesgated. • 1.47 V to drive 10 mA cm −2 in the electrolytic cell in 1.0 M KOH and 0.33 M urea. Exploring high-efficient catalysts to reduce the voltage of the electrolytic cell is pivotal for large-scale hydrogen production, and using other electrochemical reactions to replace inert oxygen evolution reaction (OER) is also a feasible way. In this paper, a series of Ni Co precursors supported by carbon cloth (CC) were prepared by hydrothermal method and subsequently treated with phosphating and oxidation, respectively. The phosphating products and oxidation products were used for hydrogen evolution reaction (HER) and urea oxidation reaction (UOR), respectively. The materials morphology and electron configuration were also controlled by adjusting relative Ni Co content in the precursors. Furthermore, the effects of different Ni-Co ratios on electrocatalytic activity under the same crystal structure were discussed in detail. Benefited from the optimum electron structure and maximum active sites, Ni 2 Co 1 -P/CC displayed the best HER catalytic performance, with an overpotential of 79 mV to reach 10 mA cm −2 . On account of the comparatively low theoretical oxidation voltage of urea, Ni x Co 3−x -O/CCs displayed a much lower working potential in urea-containing electrolyte than the urea-free electrolyte. Thereinto, Ni 1.5 Co 1.5 -O/CC showed the best UOR catalytic performance, with a potential of 1.362 V at η 10 in 1.0 M KOH and 0.33 M urea. With the combination of the above catalysts, it needed only 1.47 V to drive the current density of 10 mA cm −2 in the electrolytic cell for hydrogen production via UOR.