Synthesis of carbon–PtAu nanoparticle hybrids originating from triethoxysilane-derivatized ionic liquids for methanol electrooxidation and the catalytic reduction of 4-nitrophenol

Abstract

A facile and effective procedure for the synthesis of PtAu nanoparticles–carbon (PtAu–C) via the carbonization of triethoxysilane-derivatized ionic liquids is reported. A triethoxysilyl-functionalized ionic liquid, 1-methyl-3-[3-(triethoxysilyl)propyl]imidazolium chloride ([Si-pim][Cl]) was synthesized and anion-exchanged with a Pt precursor (H₂PtCl₆) and a Au precursor (HAuCl₄) to form [Si-pim][PtCl₆]_x[AuCl₄]_y (the suffixes x and y represent the relative molar ratios of Pt and Au in the feed, respectively). The carbonization of [Si-pim][PtCl₆]_x[AuCl₄]_y, followed by hydrofluoric acid (HF) etching, produced Pt_xAu_y–C hybrids. The composition of the Pt_xAu_y alloy NPs can be controlled simply by adjusting the feed ratio in the metal precursor solution. The electrocatalytic properties of the prepared Pt_xAu_y–C hybrids were determined by the composition of the alloy NPs. The resultant Pt–C hybrids show high electroactivity towards methanol oxidation in an acidic medium, while Pt₄Au₁–C shows high activity towards the reduction of 4-nitrophenol. The present study provides a highly efficient approach for the development of high-performance noble metals and their alloy-based catalysts.