High-temperature modification of sibunit for its application as a support for ruthenium catalysts in ammonia synthesis

Abstract

The effect of high-temperature (1400-2200°C) treatment of the carbon material Sibunit on its structural properties was studied. High-temperature treatment leads to structural ordering of the initial Sibunit. As a result of preliminary graphitization, specific surface area decreases by a factor of 10, but thermal stability increases. A good correlation between XRD, Raman spectroscopy and TGA data is observed. For the Sibunit sample treated at 2200 °С, the interplanar distance d(002) estimated by XRD decreases by 0.05 Å in comparison with the initial Sibunit, ID/IG decreases from 1.59 to 1.18, and the 2D line substantially increases, which testify to the structural ordering. According to TGA, the temperatures corresponding to the onset of oxidation, 50% oxidation and the end of oxidation of Sibunit calcined at 2200 °С are synchronously shifted by 100 °С with respect to the initial Sibunit.