Synthesis of nanoporous carbide-derived carbon by chlorination of titanium silicon carbide

Synthesis of nanoporous carbide-derived carbon, CDC, by extraction of titanium and silicon from Ti3SiC2 by chlorine is discussed in this work. Thermodynamic simulations using a Gibbs free energy minimization program provided general guidelines to the experimental design. Raman spectroscopy, X-ray diffraction, and electron microscopy studies showed that the structure of CDC depends on the chlorination temperature. The low temperature synthesis resulted in an amorphous CDC structure. Noticeable graphite formation starts above 800 °C and well ordered graphite ribbons of 1–3 nm in thickness form at 1200 °C. The macroscopic volume and shape of Ti3SiC2 preform were preserved during the transformation. However, the chlorination resulted in the formation of cracks between the former grains of the polycrystalline Ti3SiC2 preform. These cracks are believed to be caused by a contraction in the direction perpendicular to the basal planes of Ti3SiC2. The synthesized nanoporous carbon demonstrated excellent sorption properties. Energy dispersive X-ray spectroscopy studies showed that Ti3SiC2 material chlorinated at 400 °C is capable of trapping over 40 wt.% of Cl2.