RESUMO
Nanoparticles are key components in the advancement of future energy technologies, thus, strategies for preparing nanoparticles in large volume by techniques that are cost-effective are required. In the substitution of fossil-fuels by renewable energy resources, nanometer-sized particles play a key role for synthesizing energy vectors from varying and heterogeneous biomass feedstocks. They are extensively used in reformers for the production of hydrogen from solid, liquid, or gaseous energy carriers. Catalyst activities depend critically on their size-dependent properties. Nanoparticles are further indispensable as electrocatalysts in fuel cells and other electrochemical converters. The desire to increase the activity per unit area, and decrease the necessary amount of the expensive catalytic standard, platinum, has spurred innovative approaches for the synthesis of platinum-alloy nanoparticles by wet chemistry, colloidal routes, or physical techniques such as sputtering.
RESUMO
Self-assembled monolayers have evolved into one of the best established self-assembly systems with high relevance in a scientific and applied context. So far, however, virtually exclusively thiol functional groups have been used for the investigation of fundamental processes on metal surfaces. In this paper, an alternative binding group, the dithiocarbamate (DTC) group, is re-visited. Complete SAM formation with new layer properties characteristically different from thiol SAMs is demonstrated for mono-functional acyclic and bifunctional cyclic dithiocarbamates on Au111 by X-ray photoelectron spectroscopy, cyclic voltammetry, and scanning tunneling microscopy. Furthermore, the chemical adsorption and voltammetric desorption reactions are quantitatively determined. The resonant bi-dentate structure of the DTC provides a characteristically different molecule-metal coupling compared to the thiols and makes the DTC an interesting system for molecular electronics.