Intermetallic Pd3Pb nanobranches with low-coordinated surface atoms for highly efficient ethanol oxidation reaction

Abstract

Pd based bimetallic nanocrystals (NCs) with low-coordinated surface atoms endow a tremendous ability to modify electronic properties and have the synergistic effect to improve electrocatalytic performance. Among various bimetallic NCs with different compositions, intermetallic Pd-Pb NCs can improve the poisoning tolerance of surface active sites during electrocatalytic reactions. In addition, Pb can provide abundant oxygen-containing species (OHads) and has the ability to cleavage the C–C bond during electrocatalysis that can hinder the production of COads intermediate species, thereby improving ethanol oxidation reaction (EOR) performance. Herein, we report a wet-chemical method for synthesizing highly uniform Pd3Pb nanobranches (NBs). The growth process of Pd3Pb NBs was controlled using ascorbic acid as a reductant, oleylamine as a solvent, 1-octadecene as a surfactant, and ammonium bromide as a shape-directing agent. Their unique NB morphology makes them suitable as electrocatalysts, attributed to the effective adsorption of ethanol and (OH)ads and enhanced removal capability of intermediates adsorbed on the active site of Pd3Pb NBs due to the intermetallic Pd–Pb composition and high density of low-coordinated surface atoms in Pd3Pb branches that can enhance EOR in alkaline media. The prepared Pd3Pb NBs exhibited significantly higher mass activity than Pd3Pb nanocubes and commercial Pd/C catalysts.