Anisotropic gold nanoparticles: Preparation and applications in catalysis

Despite the high amount of scientific work dedicated to the gold nanoparticles in catalysis, most of the research has been performed utilising supported nanoparticles obtained by traditional impregnation of gold salts onto a support, co-precipitation or deposition-precipitation methods which do not benefit from the recent advances in nanotechnologies. Only more recently, gold catalyst scientists have been exploiting the potential of preforming the metal nanoparticles in a colloidal suspension before immobilisation with great results in terms of catalytic activity and the morphology control of mono- and bimetallic catalysts. On the other hand, the last decade has seen the emergence of more advanced control in gold metal nanoparticle synthesis, resulting in a variety of anisotropic gold nanoparticles with easily accessible new morphologies that offer control over the coordination of surface atoms and the optical properties of the nanoparticles (tunable plasmon band) with immense relevance for catalysis. Such morphologies include nanorods, nanostars, nanoflowers, dendritic nanostructures or polyhedral nanoparticles to mention a few. In addition to highlighting newly developed methods and properties of anisotropic gold nanoparticles, in this review we examine the emerging literature that clearly indicates the often superior catalytic performance and amazing potential of these nanoparticles to transform the field of heterogeneous catalysis by gold by offering potentially higher catalytic performance, control over exposed active sites, robustness and tunability for thermal-, electro- and photocatalysis. (C) 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.