Platinum particles of 50 nm diameter and 15 MI height at 200 nm spacing have been prepared on an oxidized silicon wafer using electron beam lithography. These particles were cleaned of surface carbon with low energy (400 eV) neon ion sputtering. The rate of ethylene hydrogenation over this new model catalyst was measured in a UHV chamber equipped with a high pressure cell for catalytic reaction. Measured turnover numbers are on good agreement with previous work. Atomic force microscopy (AFM) and temperature programmed desorption (TPD) indicate the sample structure remains unaltered by the cleaning and the catalytic reaction.