Improving the electrocatalytic activity of Pd nanoparticles through electronic coupling interaction with a Ni2P–MoS2 hybrid support for ethanol electro-oxidation in an alkaline medium†

Abstract

To improve the performance of direct ethanol fuel cells (DEFCs), which are hindered by traditional catalysts, having matters pertaining to stability, activity, and selectivity in reaction environments, various electrocatalysts such as Pd/Ni₂P, Pd/MoS₂, and Pd/Ni₂P–MoS₂ were synthesized using the microwave-assisted NaBH₄–ethylene glycol reduction method. The research findings suggest that the Pd/Ni₂P–MoS₂ catalyst we developed had the highest activity (1579 mA mg_Pd⁻¹), approximately 21 times greater than that of commercial Pd/C. The stability of the electrocatalysts were examined using chronoamperometry (CA) and cyclic voltammetry (CV) measurements, which indicated that the Pd/Ni₂P–MoS₂ electrocatalyst had good stability towards the ethanol oxidation reaction (EOR) in alkaline electrolyte. Electrochemical impedance spectroscopy (EIS) analysis showed that the Pd/Ni₂P–MoS₂ electrocatalyst had lower charge transfer resistance, indicating better electrochemical kinetics. According to XRD, HR-TEM, XPS, and electrochemical analysis, the enhanced electrocatalytic activity, long-term stability of the Pd/Ni₂P–MoS₂ electrocatalyst were attributable to the interface synergism as well as electronic and strain effects between the Pd, Ni₂P, and MoS₂ interactions. This resulted in a downshift in the d-band center of the Pd/Ni₂P–MoS₂ electrocatalyst, weakening intermediate adsorption and the adsorbate metal interaction.