Surface functionalized silica as a toolkit for studying aqueous phase palladium adsorption and mineralization on thiol moiety in the absence of external reducing agents

Biological templates such as virions or protein assemblies have several surface functional groups that can complicate the elucidation of the fundamental mechanism(s) governing the sorption and mineralization of metals on the surface of the template. Surface functionalized silica nanoclusters with hydroxyl, amine, or thiol groups serve as surrogates for understanding the interaction between individual amino acid functionalities and inorganic precursors. Analysis of palladium ion uptake on the functionalized silica enabled the investigation of a new palladium mineralization strategy using thiol surface moieties in the absence of external reducing agents. This study reveals the nature of the palladium-thiol interaction and the resulting self-reduction mechanism that produces the metal palladium nanolayer on the thiol-terminated silica. This surface functionalized silica approach is thus an effective toolkit for exploring the fundamentals of metal precursor sorption on surface functional groups, and for developing new metal deposition methodologies. (C) 2010 Elsevier Inc. All rights reserved.