Adsorption of CO on Thin Layers of Pt on Sn - ICS82 Abstract Submission Form

Fuel cells are electrochemical devices which convert chemical energy to electrical energy in a much more efficient and clean manner compared combustion engines. Typically, these devices utilize pure hydrogen and air that reacts on Pt based catalyst in the anode and the cathode respectively. Never the less the cost of Pt and its poisoning by CO in the ppm level in hydrogen prevents their commercialization market. Highly dispersed very thin layers of Pt on metallic Sn is being studied in our group. This approach may provide high utilization of Pt as well co-catalysis of adsorbed CO removal from Pt surface via a well-known Pt-Sn bi-functionality mechanism1,2.

PtSn alloys and their CO adsorption have been reported before. However, this research deals with tin coated by Pt and not with an alloy. The effect of various number of Pt(111) slabs on a well-defined core of Sn was studied. The effect of Pt layer number on the adsorption energy of CO was studied in comparison to the adsorption energy of CO over pure Pt.

The approach in this research was mainly computational. The calculations have been carried out using the Vienna Ab initio Simulation Program (VASP) using periodic boundaries, PAW PBE pseudopotentials and default cut off energies were used. According to the computational result, the coated Pt on a tin core changes the adsorption energy of CO on selected sites and geometrical configurations. Correlation between the number of Pt slabs and the adsorb CO adoption energy was found. Reducing the adsorption energy was demonstrated on a single atomic layer slab.

Reference

(1) Wang, K.; Gasteiger, H. a.; Markovic, N. M.; Ross, P. N. On the Reaction Pathway for Methanol and Carbon Monoxide Electrooxidation on Pt-Sn Alloy versus Pt-Ru Alloy Surfaces. Electrochim. Acta 1996, 41 (16), 2587–2593.

(2) Mukerjee, S.; Urian, R. C. Bifunctionality in Pt Alloy Nanocluster Electrocatalysts for Enhanced Methanol Oxidation and CO Tolerance in PEM Fuel Cells: Electrochemical and in Situ Synchrotron Spectroscopy.