Room temperature syntheses of surfactant-free colloidal gold nanoparticles: The benefits of mono-alcohols over polyols as reducing agents for electrocatalysis

Abstract

Developing sustainable strategies for energy conversion and chemical production remains a general challenge that can be addressed by the development of sustainable syntheses of nanocatalysts. Here, we explore colloidal syntheses of gold nanoparticles obtained at room temperature by a simple route that requires only an alcohol as reducing agent, water, a base and a gold precursor, without the need for extra reducing agents or stabilizers. To date, polyols-based syntheses were preferred but they suffer from multiple drawbacks related to the high viscosity and high boiling point of the solvents. We recently reported on the opportunities to use methanol and ethanol as alternative reducing agents. We illustrate further the benefits of using methanol and ethanol as reducing agents to prepare ca. 10–20 nm gold nanoparticles. We characterize the nanoparticles by UV–vis absorption, transmission electron microscopy and X-ray diffraction. The nanoparticles prepared in alkaline mono-alcohols lead to nanocatalysts up to three times more active for the ethanol and ethylene glycol electro-oxidation than nanoparticles prepared using polyols.