Nanostructured Palladium Catalysts On Viral Templates

Biological macro/supramolecules ranging from DNA, proteins and viruses have gained substantial attention as inorganic materials synthesis templates over the past two decades. A large array of nanometer scale materials from particles to wires have been synthesized for a variety of applications in nanoelectronics, biomedical imaging, catalysis and energy. Of particular interest are viruses, which offer attractive templating platforms due to their precise dimensions and robust structures combined with genetic manipulation to confer additional functionalities and material-specific adsorption sites.

We present facile routes to synthesize nanostructured palladium catalysts by exploiting unique structural, chemical and biological properties of genetically modified Tobacco Mosaic Virus (TMV) as nanotemplates. Specifically, TMV is a biologically derived nanotube with 18nm diameter, 300nm length and 4nm inner channel, and consists of 2130 identical coat proteins helically wrapped around a 6.4kb single strand genomic mRNA. Due to its safety, well-controlled dimensions and extraordinary stability, TMV has been extensively enlisted for nanowire and inorganic nanoparticle synthesis in a number of studies. Particularly, we harness precisely spaced thiol functionality displayed on the outer surface of each coat protein via small genetic modification that provides enhanced biosorption for readily controllable palladium nanoparticle synthesis. Through in-depth characterization studies via Atomic Force Microscopy (AFM) and Grazing Incidence Small Angle X-ray Scattering (GISAXS), we envision to address critical challenges in nanocatalysis and to gain fundamental understanding of nanoparticle growth kinetics. In this presentation, our recent progress on the fabrication of nanostructured palladium catalysts and catalytic reaction studies on two model reactions, namely dichromate reduction and Suzuki coupling reaction, will be highlighted.