Benefits of Surfactant-Free Nanomaterials for Catalysis: Size Effects of Gold Nanoparticles for Alcohol Electro-Oxidations

Nanocatalysts are at the forefront to study and exploit several chemical processes. Simple preparation methods of nanomaterials greatly benefit to various fundamental studies and facilitate the development of nanocatalysts towards real-life applications. Here, an easily implementable surfactant-free colloidal synthesis, simply achieved in alkaline mixtures of water and mono-alcohol (e.g. ethanol), performed at room temperature in the case of gold nanoparticles, and compatible with the principles of Green Chemistry, is exploited and further developed to easily perform size-effects studies in catalysis. Gold nanoparticles in the size range of 5 to 22 nm are easily prepared from a solution of 0.5 mM HAuCl4, 2 mM NaOH and 20 v.% ethanol or methanol, and by initiating the synthesis in different simple ways: sonochemistry, stirring, manual shaking, using different grades of precursors, using different solvents. The nanomaterials are shown to be ideal model systems to study size effects in catalysis with the example of alcohol electrocatalytic oxidations performed in alkaline media.