Realization of the dehydrogenation pathway of formic acid oxidation by ultra-small core–shell Au–Pt nanoparticles with discrete Pt shells†
Abstract
In this work, ultra-small core–shell Au–Pt nanoparticles with discrete Pt shells (denoted as USCSD Au–Pt NPs) were successfully prepared by Fe(II)-assisted one-pot co-reduction of Au(III) ions and an ultra-low concentration of Pt(II) ions in citrate solution. In the as-prepared USCSD Au–Pt NPs, the Pt atoms on their outer surfaces are effectively isolated by Au atoms (denoted as a discrete shell, CSD). Furthermore, the as-prepared USCSD Au–Pt NPs are determined to be USCSD Au61.2@Au27.3Pt11.5 NPs with an average size of 2.3 nm using a number of characterization techniques, including transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), cyclic voltammetry (CV), CO stripping voltammetry and X-ray photoelectron spectroscopy (XPS). Moreover, the as-prepared USCSD Au61.2@Au27.3Pt11.5-NP/C catalysts towards the formic acid oxidation reaction (FAOR) proceed through the direct pathway (dehydrogenation). In addition, their mass activity and specific activity towards the FAOR are 6.91 A mgPt−1 and 4.88 mA cm−2, which are about 16.8 and 7.33 times higher than those (0.4 A mgPt−1 and 0.67 mA cm−2) of commercial Pt/C catalysts, respectively.