Metal- and Metal Oxide-Supported Platinum Monolayer Electrocatalysts for Oxygen Reduction
Our 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, catalystsí 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.
1. Pt monolayer Electrocatalysts for O2 reduction: atomic-level synthesis, Electronic properties of Pt monolayers on single crystals and nanoparticles, Pt-support interactions; Structure-activity correlations; Pd alloy electrocatalysts; In situ spectroscopic studies of the O2 reduction intermediates; Kinetic analyses of the O2 reduction reaction.
first Pt monolayer-level electrocatalyst. No change in performance during
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.
J. Zhang, K. Sasaki, E. Sutter, R. R. Adzic, Stabilization of Platinum Oxygen Reduction Electrocatalysts Using Gold Clusters, Science, 315 (2007) 220.
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 and Energy Efficiency and Renewable Energy under contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
Last Modified: June 28, 2012