Dependence of the adsorption and catalytic properties of a copper-platinum catalyst on the structure of metal particles and the composition of the catalyst surface

The kinetics of H2 desorption from the surface of a copper-platinum catalyst deposited on silica gel ([1 wt % Pt + 0.15 wt % Cu]/SiO2) and the kinetics of C6H12 dehydrogenation were studied. The effects of copper introduction in a platinum catalyst on the structural characteristics of platinum particles, the com- position of their surface, and the effects of plasmochemical treatments on these parameters were studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The metal-H atom bond energies (EPt-H) and the catalytic activity were found to increase in the presence of Cu. This was explained by the for- mation of new hydrogen adsorption centers (due to the Cu+δ adatoms) and catalytic centers composed of Cu +δ adatoms and carbon atoms. The mean diameter of Pt particles (D) increased twofold. The microstresses (ε) in the particles increased after the catalyst was treated with glow discharge plasma in Ar and O 2 and with high-frequency plasma in H2 (HF-H2). The observed changes in the bond energy EPt-H and kinetic param- eters were explained by the increase in microstresses in Pt particles. © 2011 Pleiades Publishing, Ltd.