Enhanced electrocatalytic oxidation of methanol and ethanol using PdNi alloys supported on nitrogen-phosphorus co-doped carbon

Herein, a series of PdNi alloy electrocatalysts supported on N, P-codoped carbon (denoted as PdNi/NPC) with controlled Pd:Ni mass ratios (Pd 1 Ni 2 /NPC, Pd 1 Ni 1 /NPC, and Pd 2 Ni 1 /NPC) were synthesized. Among them, Pd 1 Ni 1 /NPC demonstrated superior mass activity and stability for both the methanol and ethanol oxidation reactions. For the ethanol oxidation reaction (EOR) in 1.0 M KOH containing 1.0 M CH 3 CH 2 OH, the mass activity of Pd 1 Ni 1 /NPC reached 2.77 A mg Pd -1 , which is about 12-fold higher than that of commercial Pd/C. Moreover, after a 10,000 s chronoamperometry (CA) stability test, it retained a mass activity of 2.61 A mg Pd -1 . Under alkaline conditions (1.0 M KOH + 1.0 M CH 3 OH) for the methanol oxidation reaction (MOR), Pd 1 Ni 1 /NPC exhibits a mass activity of 1.24 A mg Pd -1 , surpassing that of commercial Pd/C by a factor of six. Following 10,000 s of stability testing, the catalyst maintained a mass activity of 1.17 A mg Pd -1 . These improvements are ascribed to the electronic interaction between Pd and Ni, involving electron transfer from Pd to Ni. This interaction weakens the adsorption of reaction intermediates (e.g., CO ad ), promotes CO desorption and oxidation, and thereby enhances the durability of PdNi/NPC. The optimal catalytic performance observed at a Pd:Ni mass ratio of 1:1 indicates that an appropriate stoichiometry is crucial for enhancing electrocatalytic activity.