Influence of Oxidative Treatment and Platinum Content on the Stability of the Pt/Sibunit System in an Oxidizing Atmosphere at Elevated Temperatures

The effect of elevated temperatures on the textural and structural characteristics of the carbon material Sibunit in an oxygen-containing atmosphere was studied depending on the preliminary treatment of Sibunit with HNO3 and the presence and the amount of an active component (Pt). According to the results of thermogravimetry, the preliminary treatment of Sibunit with HNO3 led to an increase in the temperature range of carbon oxidation, while the introduction of Pt led to a decrease in this temperature range. It was found that an exposure of Pt/Sibunit samples for 4 h in a nitrogen–air mixture at a temperature of 400°C led to an increase in the total volume and average pore diameter with a slight change in the specific surface area, and the average particle size of platinum increased from 2 to 5 nm.