Results and discussion
X-ray diffraction analysis was performed to study the effect of thermal treatment temperature and metal phase the concentration on the electroactivity. XRD pattern of the as-synthesized systems is typical for all gel products after air-drying (Figures 1, 2 and 3) and shows predominantly only amorphous structure. The XRD diffractogram measured for Pt/SnO2 samples presents reflections becoming more defined from the tetragonal crystallographic phase (cassiterite) of SnO2 after heating (temperatures from 373 K to 773 K). For higher temperatures, the diffraction peaks become progressively more intense and sharp. Miller indexes are indicated on each diffraction peak. The reflection peaks at ~26 (2theta)/{110}, ~33 (2theta)/{101} at ~51 (2theta)/{211}, at ~65 (2theta)/{301}, can be readily indexed to a tetragonal rutile structure of SnO2 (PDF 4+ Card File No. 04-003-5853).