Developing highly active and durable Pd-based electrocatalysts for the ethanol oxidation reaction (EOR) in alkaline media remains a key challenge for the advancement of direct ethanol fuel cells (DEFCs). Herein, we report a facile one-pot solvent-regulated strategy for the direct synthesis of hollow spherical PdPb alloy nanoparticles (NPs), in which the nanoscale morphology and architecture can be precisely tuned by adjusting the ratio of oleylamine (OAm) to N,N-dimethylformamide (DMF). Systematic structural characterization reveals a solvent-driven morphological evolution from spiky spheres to hollow nanospheres, governed by anisotropic growth kinetics and the Kirkendall cavitation process. The hollow PdPb nanospheres exhibit an upshifted Pd d-band center and a high electrochemically active surface area, enabling the optimized adsorption of reaction intermediates. As a result, the optimized PdPb-S1 catalyst delivers significantly enhanced mass activity, favorable charge-transfer kinetics, and superior resistance toward intermediate poisoning during alkaline ethanol oxidation. Kinetic analyses based on Tafel plots, electrochemical impedance spectroscopy, concentration-dependent reaction orders, and Arrhenius behavior collectively demonstrate that the hollow nanoscale architecture and electronic modulation synergistically promote the intrinsic reaction kinetics. Moreover, PdPb-S1 maintains remarkable cycling stability and long-term durability under prolonged electrochemical operation. This work elucidates the critical roles of solvent-controlled morphology engineering and electronic structure modulation in Pd-based alloy catalysts, providing a rational design strategy for high-performance electrocatalysts in alkaline fuel cell applications.
Liu et al. (Mon,) studied this question.