The local coordination structure plays a critical role in determining the catalytic behavior of platinum (Pt)-based alloy nanomaterials, yet its influence on bifunctional electrocatalysis remains insufficiently understood. Herein, PtNi nanocrystals with a locally asymmetric, Pt-dominant coordination structure were developed as efficient bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and the ethylene glycol oxidation reaction (EGOR). Synchrotron X-ray absorption spectroscopy reveals unequal Pt–Ni/Ni–Pt coordination numbers together with reconstructed local bond distances, demonstrating that the PtNi nanocrystals deviate from a random alloy structure and possess pronounced heteronuclear coupling. Benefiting from this unique local coordination environment, the PtNi nanocrystals exhibit mass activity (MA) of 0.74 and 3.13 A mg Pt –1 for ORR and EGOR, respectively, corresponding to 6.73- and 3.86-fold enhancements over commercial Pt/C, together with excellent durability. Combining with density functional theory (DFT) calculations and in situ electrochemical infrared spectroscopy results confirms that unique PtNi nanocrystals show an upshifted d-band center (−2.03 eV), leading to stronger adsorption of O 2 and EG on PtNi than on monometallic Pt, thus promoting activation of reactant and formation of key oxygenated intermediates during both ORR and EGOR. This work provides mechanistic insight into the role of local coordination engineering in regulating bifunctional electrocatalysis for the design of advanced Pt-based alloy catalysts.
Liao et al. (Thu,) studied this question.