EFFECT OF Pt, Pd, AND Cs+ ADDITIVES ON THE SURFACE STATE AND CATALYTIC ACTIVITY OF WO3 IN OXIDATION OF HYDROGEN

We have shown that additions of Pt(Pd) and Cs+ to WO3 significantly increase its specific surface area and catalytic activity in H2 oxidation. After reduction, the promoted specimens contain the phases WO3, WO2.9, HxWO3; and in the case of Cs+ additions, CsxWO3. According to X-ray photoelectron spectroscopy (XPS), the Pt and Pd have an oxidation state close to 0, while tungsten has a +5 oxidation state. The W:O ratio indicates the content of oxygen vacancies in the surface layer. The data are explained taking into account hydrogen spillover from Pt(Pd) to the support.