LAUSR

Abstract The development of high active and durable electrocatalysts is of critical importance for the commercial viability of direct alcohol fuel cells. Here, hollow N-doped carbon spheres (HNCSs) were prepared by using a polydopamine-assisted method for supporting flowerlike PtPd alloy nanoparticles which were synthesized by the reduction of H2PtCl6 and Na2PdCl4 with ascorbic acid. The effect of Pt-to-Pd molar ratios on the catalytic activity was investigated for methanol, ethanol and ethylene glycol electrooxidation (MOR, EOR and EGOR). Electrochemical measurements demonstrated that PtPd/HNCSs (only 2 wt.%) exhibited higher catalytic activity, stability and tolerance to CO poisoning than commercial Pt/C (20 wt.%) catalyst in the alcohols oxidation. It could be attributed to the structural and compositional advantages of the synergistic effect of Pt and Pd besides large specific surface area and mesoporous structure of HNCSs. After 200 scanning cycles, the peak currents density of Pt3Pd1/HNCSs still remained 77.8%, 88.9% and 93.9% of the initial cycle in MOR, EOR and EGOR, respectively. Meanwhile, the kinetic study confirmed that the MOR, EOR and EGOR processes were diffusion-controlled and irreversible.