Comparative Study of the Catalytic Activities of Ni, NiCo, and PtNiCo in Ethanol Electrooxidation: Contributions of Individual Metals

Abstract

This study compares the catalytic activity of Ni, NiCo, and PtNiCo in the ethanol electrooxidation reaction to elucidate the role of each metal. The catalysts were synthesized via electrodeposition at room temperature and characterized using energy-dispersive X-ray spectroscopy and X-ray diffractometry techniques. Catalytic activity was evaluated through various electrochemical tests, including electrochemical impedance spectroscopy, linear sweep voltammetry, and chronoamperometry. Ethanol electrooxidation tests conducted via cyclic voltammetry over 1000 cycles revealed a progressive increase in catalytic activity among the three catalysts, with PtNiCo exhibiting the highest performance. The synergistic effect of the three metals resulted in a low charge transfer resistance (3.46 Ω), a small Tafel slope (156 mV/decade), a high peak current density (32.06 mA/cm²), a low I_f/I_b ratio, and an enhanced reactant diffusion coefficient. These findings provide valuable insights for designing efficient and high-performance tri-metallic catalysts.