Multipod Pd-Cucurbit[6]uril as an Efficient Bifunctional Electrocatalyst for Ethanol Oxidation and Oxygen Reduction Reactions

Pd species have been extensively studied as electrocatalysts due to their superior catalytic activities. Especially, it is vital for precisely regulating the nanoscale structure of Pd-based nanomaterials for efficient catalysis. Here, the well-dispersed multipod Pd nanoparticles (NPs) stabilized by cucurbit[6]uril (CB[6]) were successfully prepared by a wet chemical method, denoted as multipod Pd-CB[6]. The resulting multipod Pd-CB[6] was applied as a suitable bifunctional catalyst for direct ethanol fuel cells, with desired electrocatalytic activity and stability toward both anodic ethanol oxidation reaction (EOR) and cathodic oxygen reduction reaction (ORR). Impressively, the interaction between CB[6] and Pd NPs contributes to the good electrocatalytic activity and exceptional stability. The peak current of multipod Pd-CB[6] for EOR was 3.02 times higher than that of commercial Pd/C. Moreover, the improved ORR activity of multipod Pd-CB[6] was comparable to that of Pt/C. The remarkable stability of multipod Pd-CB[6] was also obtained for both ORR and EOR. This work provides a promising strategy to prepare well-stabilized Pd NPs with good electrochemical activity and stability toward EOR and ORR.