Metal and Metal Oxide-Supported Platinum Monolayer Electrocatalysts for Oxygen Reduction
Research is directed towards the synthesis and characterization of Pt
monolayer electrocatalysts supported by metal, metal alloy, non-noble metal
- noble metal core - shell and oxide nanoparticles, or single crystal
extended surfaces. This new approach has the potential to yield
electrocatalysts with the lowest Pt content and improved catalytic activity,
which can reduce the cost of fuel cells. In a parallel effort we are
developing new improved Pd alloy electrocatalysts that can replace Pt in
fuel cell cathodes. The structural, electronic and catalytic properties of
electrocatalysts for O2 reduction, methanol, ethanol and CO
oxidation reactions are studied by in situ and ex situ
synchrotron radiation, surface science, infrared and electrochemical
techniques. The synthesis of Pt monolayer electrocatalysts is based on the
unique method that involves a Pt monolayer deposition by displacement of an
adsorbed Cu monolayer. Understanding the phenomena which determine the
catalytic properties, structure-activity correlations, catalysts’ stability,
segregation, structure and ordering of atomic and molecular monolayers at
electrochemical interfaces is sought by combining the above techniques and
kinetic analyses of the O2 reduction reaction with intensive
density functional theory calculations. Research Activities: Electrocatalysis
2. Pt submonolayer on Ru (PtRu20) Electrocatalysts: H2, CO and reformate H2 oxidation; Pt content is 1/10 of that in commercial catalysts, high CO tolerance; Oxidation of Methanol and Ethanol; Adsorbate-Surface Interactions. Research Activities Surface Electrochemistry: To obtain a true microscopic description of electrochemical interfaces, structural and electronic properties of atomic and molecular monolayers on single-crystal and nanoparticle substrates are investigated using in situ scanning tunneling microscopy, surface x-ray scattering and x-ray absorption spectroscopy.
Recent Publications J. Zhang, K. Sasaki, E. Sutter, R. R. Adzic, Stabilization of Platinum
Oxygen Reduction M. Shao, P. Liu, J. Zhang, R.R. Adzic, Origin of Enhanced Activity in
Palladium Alloy Electrocatalysts for Oxygen Reduction Reaction, J. Phys.
Chem. B.; (Article); 2007; 111(24); 6772-6775. M.H. Shao, T. Huang, P. Liu, J. Zhang, K. Sasaki, V.B. Vukmirovic, R. R. Adzic, Palladium Monolayer- and Palladium Alloy- Electrocatalysts for Oxygen Reduction, Langmuir (Electrochemistry special issue) 22 (2006) 10409. F.H.B. Lima, J. Zhang, M. H. Shao, K. Sasaki, M. B. Vukmirovic, E. A.
Ticianelli, R. R. Adzic, Catalytic Activity - d-band Center Correlation for
the O2 Reduction Reaction on Pt in Alkaline Solutions, J. Phys. Chem. C,
111(2007) 404. J. Zhang, M. B. Vukmirovic, Y. Xu, M. Mavrikakis, R. R. Adzic,
Controlling the Catalytic Activity of Platinum Monolayer Electrocatalysts
for Oxygen Reduction with Different Substrates, Angew. Chem.. Int.
Ed. 117 (2005) 2170. J. X. Wang,; N. M. Markovic,; R. R. Adzic, Simulation of O2
reduction on Pt(111) in Acid Solutions: Intrinsic Kinetic Parameters and
anion adsorption effects. J. Phys. Chem. B, 108 (2004) 4127.
Junliang Zhang, Miomir B. Vukmirovic, Kotaro Sasaki, Anand Udaykumar
Nilekar, Manos Mavrikakis, and Radoslav R. Adzic, Mixed-Metal Pt Monolayer
Electrocatalysts for Enhanced Oxygen Reduction Kinetics, J. Am. Chem.
Soc., 127 (2005) 12480. M.H. Shao, P. Liu, R.R. Adzic, Superoxide is the intermediate in the oxygen reduction reaction on platinum electrode. J. Am. Chem. Soc., 128 (2006) 7408. J. Zhang, F.H.B. Lima, M. H. Shao, K. Sasaki, J.X. Wang, J. Hanson, R. R. Adzic, Platinum monolayer on non-noble metal - noble metal core-shell nanoparticles electrocatalysts for O2 reduction, J. Phys. Chem. B, 109 (2005) 22701-22704. M.H. Shao, K. Sasaki, R.R. Adzic, Pd-Fe nanoparticles as electrocatalysts for oxygen reduction. J. Am. Chem. Soc., 128 (2006) 3526.
Supported by the the Division of Chemical Sciences, Geosciences, and Biosciences of the Office of Basic Energy Sciences of the Office of Science under contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Last Modified: January 31, 2008 |