Surface modification of platinum with copper and by plasma-chemical treatment and the effect on H-Pt bond energy

Kinetics of H-2 desorption from the surface of a platinum catalyst applied to silica gel, as well as from the surface of the same catalyst modified with a copper additive, is studied. Desorption of hydrogen was studied both before and after the treatment of the catalyst in the electric glow discharge of argon or oxygen or in the high-frequency H-2 plasma. The H-Pt bond energy was found to increase upon the introduction of copper additive and decrease upon the plasma-chemical treatment of copper-platinum specimens. In the latter case, the size of metal particles increases and the microstrain in them decreases. The observed changes in H-Pt bond energy are explained by the change in the electronic state of the surface and the increase in the number of metal structure defects.