Nanoparticles. Nanomaterials and nanoparticles (NPs), e.g. gold (Au) NPs, express unique properties that are relevant for applications in multiple areas of research and development, e.g. in catalysis, sensing, optics, electronics or medicine . Regardless of the application considered, the full exploitation of NP properties require their controlled syntheses . The synthesis would ideally be simple, safe, widely implementable and scalable. Various recipes have been reported for the preparation of Au NPs . Typically, Au NPs are obtained using wide range of chemicals playing multiple roles . The rational selection of the chemicals can therefore be tedious. There is also an increasing awareness and need for the NPs to be produced by greener and more sustainable methods . Sustainable syntheses. Towards the development of more sustainable syntheses, so-called surfactant-free (SF) colloidal syntheses are promising strategies. In those approaches, no additives with a molar mass higher than 100 g mol -1 apart from the metal precursor is required, as per a definition proposed and detailed elsewhere . Since in those approaches size and/or shape control cannot be achieved by the typical use of common additives such as citrates or thiols , new strategies need to be developed.