Polypyrrole@polyaniline-reduced graphene oxide nanocomposite support material and Cobalt for the enhanced electrocatalytic activity of nickel phosphide microsphere towards alkaline urea oxidation

Efficient and low-cost materials are highly demanded to improve the sluggish kinetics and stability of direct urea fuel cells for large-scale commercialization. In this study, modification of conventional nickel phoaphide (NiP) by cobalt doping via the facile solvothermal method and simultaneously dispersing prepared cobalt nickel phosphide (CoNiP) on poly (aniline-co-pyrrole)/reduced graphene oxide (PPy@PANI/rGO) as efficient and low-cost support material via simple ultrasonic/heat mediated dispersion process. The synthesized catalysts were characterized by scanning electron microscopy and an x-ray diffractometer. Furthermore, Cyclic Voltammetry tests were conducted to evaluate the performance of synthesized catalysis towards alkaline urea oxidation. The physical characterization depicts the successful formation of NiP and Co-doped NiP microsphere with a particle size of 4.306 mu m and 2.04 mu m, respectively. In addition, homogeneous distribution of the CoNiP microsphere in the structure of PPy@PANI/rGO support material was achieved. Based on the CV test, the superior electrocatalytic performance of CoNiP@PPy@PANI/rGO electrode material with a potential of 0.414V versus SCE to drive a high current density of 26.92 mAcm(-2), lower onset potential of 0.204 V versus SCE, and higher electrochemically active surface area of 2.08 x 10(-1) cm(2)mg(-1) were achieved. Furthermore, the electrochemical activities, kinetics, and stability of CoNiP@PPy@PANI/rGO remarkably outperformed the commercial NiP and CoNiP towards alkaline urea electro-oxidation. Therefore, a novel material, CoNiP@PPy@PANI/rGO, is an excellent candidate for anode electrode material in direct urea fuel cells.

Automated summary

The study focused on modifying conventional nickel phosphide by cobalt doping and dispersing the prepared cobalt nickel phosphide on poly (aniline-co-pyrrole)/reduced graphene oxide to improve the kinetics and stability of direct urea fuel cells. The synthesized catalysts showed superior electrocatalytic performance, indicating potential commercial applications.