Capping agents (organic ligands, polymers, surfactants, etc.) are a basic component in the synthesis of metal nanoparticles with controlled size and well-defined shape. However, their influence on the performances of nanoparticle-based catalysts is multifaceted and controversial. Indeed, capping agent can act as a “poison”, limiting the accessibility of active sites, as well as a “promoter”, producing improved yields and unpredicted selectivity control. These effects can be ascribed to the creation of a metal-ligand interphase, whose unique properties are responsible for the catalytic behavior. Therefore, understanding the structure of this interphase is of prime interest for the optimization of tailored nanocatalyst design. This review provides an overview of the interfacial key features affecting the catalytic performances and details a selection of related literature examples. Furthermore, we highlight critical points necessary for the design of highly selective and active catalysts with surface and interphase control.

Au-based catalysts have established a new important field of catalysis, revealing specific properties in terms of both high activity and selectivity for many reactions.

The conversion of biomass to useful chemical products requires precise catalytic properties to achieve the required activity, selectivity, and durability. Here we show, through optimized colloidal synthesis, the tandem control of Pd size and site availability for the directed hydrogenation of the bioderived intermediate furfural. Adjusting the temperature of colloidal reduction dictates the size of Pd nanoparticles; in some instances ultrasmall clusters of <20 atoms are achieved. However, changing the solvent system affects the PVA–Pd interaction and relative proportion of available surface sites (corners, edges, planes), allowing us to control the selectivity to the valuable hydrogenation products furfuryl alcohol and tetrahydrofurfuryl alcohol. We demonstrate, through combined experimental and computational studies, that Pd nanoparticle planes are more prone to deactivation through the formation of Pd carbide, resulting in the reduced efficacy of furfural binding. This approach to nanoparticle optimization is an important strategy for producing long-lasting, high-performance catalysts for emerging sustainable technologies.