Tungsten Carbide and Cobalt Modified Nickel Nanoparticles Supported on Multiwall Carbon Nanotubes as Highly Efficient Electrocatalysts for Urea Oxidation in Alkaline Electrolyte.

The tungsten carbide and cobalt-modified Ni-based catalyst [Ni-Co-WC/multiwall carbon nanotubes (MWCNTs)], synthesized through a sequential impregnation method, was evaluated for the urea electrooxidation in alkaline electrolyte to reduce the overpotential and increase the current density simultaneously. The as-prepared Ni-Co-WC/MWCNTs catalyst was characterized using scanning electron microscopy-EDX, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Characterization results indicate that Ni, Co, and WC nanoparticles are uniformly distributed on the MWCNTs. For the Ni-Co-WC/MWCNT electrode, the maximum current density for urea electrooxidation is more than 4 times higher than that of the Ni/C catalyst, with a reduction of 120 mV in the onset overpotential. In addition, the Ni-Co-WC/MWCNTs catalyst also shows an enhanced catalytic stability with a continuous higher current density under steady-state conditions.