Convenient construction of porous dendritic Cu-doped Ni@PPy/stainless steel mesh electrode for oxidation of methanol and urea

Abstract

In multifunctional catalysts, Ni-based alloys and compounds can be used for methanol oxidation reaction (MOR) and urea oxidation reaction (UOR). Herein, the porous dendritic NiCu@PPy/316L stainless steel mesh (SSM) electrode is prepared by dynamic hydrogen bubble template electrodeposition, followed by cyclic voltammetry electrodeposition of polypyrrole (PPy) conductive polymer on the electrode surface. Among them, dynamic hydrogen bubbles successfully assisted the formation of porous structures in the Ni-based deposition layer. In addition, the morphology of the resulting Ni-based layer further evolves from particle stacking to dendritic with high specific surface area with Cu doping. Eventually, 2-NiCu/SSM achieves current densities of 294.5 mA·cm−2 (MOR) and 278.6 mA·cm−2 (UOR) at 0.8 V, respectively. The PPy coating prevents the agglomeration of NiCu particles in the catalytic layer and further improves the persistence of the electrochemical performance. After 2000 cycles, the current densities of 2-NiCu @PPy/SSM in the new electrolyte are maintained at 89.1% (MOR) and 94.8% (UOR) of the original value, with a 10% increase for MOR and a 7% increase for UOR compared to the sample without PPy coating (2-NiCu /SSM).