The Pd-on-Au NPs currently investigated for the catalytic reduction of organic halides dissolved in water are highly useful as a model catalytic material to study in greater detail (i) the effects of mass transfer on reaction kinetics, (ii) the bi-metal distribution of the core/shell nanostructure, (iii) the nature of the catalytically active sites, and (iv) the details of the surface reaction pathway. We have successfully addressed these questions through the development of new spectroscopic techniques (gold nanoshell-based surface enhanced Raman spectroscopy and in situ x-ray absorption spectroscopy), careful synthesis methods, and the application of classical reaction kinetics analysis (e.g., experimental identification of mass transfer resistances and Langmuir-Hinshelwood mechanistic studies). Our research team and collaborators continue to deepen our understanding of bimetallic catalysts.
Y. L. Fang, K. N. Heck, P. Alvarez, and M. S. Wong, "Kinetics Analysis of Palladium/Gold Nanoparticles as Colloidal Hydrodechlorination Catalysts," ACS Catal., 1 (2), 128-138 (2011). DOI: 10.1021/cs100067k (Abstract)
L. A. Pretzer, Q. X. Nguyen, and M. S. Wong, "Controlled Growth of Sub-10 nm Gold Nanoparticles Using Carbon Monoxide Reductant," J. Phys. Chem. C, 114 (49), 21226-21233 (2010). DOI: 10.1021/jp107945d (Abstract)
Y. L. Fang, J. T. Miller, N. Guo, K. N. Heck, Pedro. J. J. Alvarez, and M. S. Wong, "Structural Analysis of Palladium-decorated Gold Nanoparticles as Colloidal Bimetallic Catalysts," Catal. Today, 160 (1), 96-102 (2011). DOI: 10.1016/j.cattod.2010.08.010 (Abstract)
K. N. Heck, M. O. Nutt, P. Alvarez, and M. S. Wong, "Deactivation Resistance of Pd/Au Nanoparticle Catalysts for Water-phase Hydrodechlorination",J. Catal. 267, 97-104 (2009)DOI: 10.1016/j.jcat.2009.07.015 (Abstract)
K.N. Heck, B.G. Janesko, G.E. Scuseria, N.J. Halas and M.S.Wong, "Observing Metal-Catalyzed Chemical Reactions in Situ Using Surface-Enhanced Raman Spectroscopy on Pd-Au Nanoshells" J. Am. Chem. Soc. , 130 (49), 1659216600 (2008). DOI:10.1021/ja803556k (Abstract)