AVS 58th Annual International Symposium and Exhibition
    Surface Science Division Wednesday Sessions
       Session SS2-WeM

Paper SS2-WeM6
Spatially Resolved Measurements of Catalytic Activity on Variable-Composition Pd-Cu and Pd-Cu-Au Thin Films using a Microfluidic Reactor Array

Wednesday, November 2, 2011, 9:40 am, Room 109

Session: Chemisorption on Metal & Oxide Nanoparticles
Presenter: Petro Kondratyuk, Carnegie Mellon University
Authors: P. Kondratyuk, Carnegie Mellon University
G. Gumuslu, Carnegie Mellon University
B.D. Morreale, National Energy Technology Laboratory
J.B. Miller, Carnegie Mellon University
A.J. Gellman, Carnegie Mellon University
Correspondent: Click to Email
A new experimental approach to mapping the relationship between composition and catalytic activity in metal alloy catalysts is presented. We apply this methodology to study H2-D2 exchange reaction on Pd-Cu and Pd-Cu-Au alloys. The activity measurements were performed on thin alloy films deposited in such a way that the elemental composition varied continuously across the film. We refer to these films as composition spread alloy films (CSAFs). CSAFs were prepared by co-deposition of Pd, Cu and Au onto a molybdenum substrate under UHV conditions. The top-layer and near-surface composition of the CSAFs were determined by low-energy ion scattering (LEIS) and X-ray photoemission spectroscopy (XPS) respectively. The activity of the alloy films in the H2-D2 exchange reaction was analyzed at atmospheric pressure using a 100-channel glass microfluidic device. During the spatially-resolved activity measurements, the microfluidic device delivers reactant gases to a 10x10 array of measurement points on the CSAF surface covering an area of 1 cm2, each measurement point corresponding to a different catalyst composition. After coming in contact with the catalyst, the gases are withdrawn for mass-spectrometric analysis through a separate set of channels. The activity-composition relationship can then be established by correlating the XPS (or LEIS) data with the product concentration in each channel of the microfluidic device.