Nanotip-induced local electric field of PdCu nano-sea urchins for selective ethanol electro-oxidation

Electrocatalysis, a form of heterogeneous catalysis, is closely associated with both catalyst properties and the catalyst/electrolyte interfacial microenvironment. Herein, we rationally design and synthesize a unique PdCu nano-sea urchins (PdCu NSUs) featured with high-curvature nanotips, by which the interfacial microenvironment is expected to be tailored to the electrocatalytic reactions. PdCu NSUs exhibit excellent activity for ethanol electrooxidation, with a specific activity of 4.11 mA cm −2 and a mass activity of 2.24 mA μg Pd −1 , and a high Faraday efficiency (FE) of 96.4% toward acetic acid. COMSOL finite element simulations confirm that the unique nanotips could induce a local electric field due to the accumulation of positive charges in the nanotips, resulting in enrichment of OH - at the catalyst surface to promote the formation of Pd−OH ads , a species required by ethanol dehydrogenation. Furthermore, DFT calculations and in-situ electrochemical Fourier transform infrared spectroscopy discover that the d-band center of Pd significantly downshifts in PdCu alloy, which facilitates the desorption of the produced acetic acid. This work provides a new electrocatalytic material with high-curvature nanotips, and also clarifies how the material morphology, by inducing local electric fields, affects the interfacial microenvironment and thus the catalytic activity and selectivity.