Ni-doped Pd nanoparticles dispersed on coarse polypyrrole granules for achieving performance synergistic optimization toward alcohol electrooxidation

Catalysts with high-efficient performance, high durability and low cost are still urgently needed to promote the wide application of direct alcohol fuel cells (DAFCs). This work prepared a PdNi/PPy composite by dispersing Ni-doped Pd nanoparticles on coarse polypyrrole (PPy) granules via facile interfacial redox and polymerization. The optimized PdNi/PPy composite possesses a porous morphology and uniform dispersion, which are key for achieving performance synergistic optimization in alcohol oxidation reactions (AORs). Specifically, for ethylene glycol oxidation (EGOR), the PdNi/PPy achieves mass activity (MA, 5577.2 mA mg Pd −1 ), specific activity (SA, 32.3 mA cm −2 ), and intrinsic activity (TOF, 6.8 s −1 ), which are 7.9, 3.0 and 2.7 times those of commercial Pd/C, respectively. It also exhibits higher activity for ethanol and methanol oxidation compared to other catalysts. Characterizations demonstrate that the synergy between Ni-doped Pd and conductive PPy significantly enhances catalytic properties. The electronic structure of Pd is optimized via Ni-doping induced d-band center modulation and efficient interfacial charge transfer through heterojunction formation. Additionally, the PPy support facilitates uniform dispersion and maximizes active site exposure. This work can offer meaningful insights for the development of advanced anode catalysts by effective doping of active metals and further strengthening of the carrier effects for DAFCs.