Preparation Technology And Mechanism Of Carbide-derived Carbon By HCl-assisted Cl₂ Etching SiC And WC

Carbide-derived carbon?CDC? is a porous carbon materials synthesized by selective etching of non-carbon atoms form different carbide crystal lattice. Due to its features of simple preparation process, controllable pore size structure and high specific surface area?SSA?, CDC has broad application prospect as electrode materials of supercapacitor, At present, the pure Cl₂ or HCl are common etching gases.CDC mainly contains micropores which prepared by Cl₂. CDC with structure of microporou-mesoporou or mesoporou-macroporou can be prepared by HCl. It is difficult to prepare CDC with micropore-mesopore-macropore structure which is suitable for the electrode materials of supercapacitor. In this work, carbide-derived carbon materials with high specific surface area and high gravimetric capacitance was synthesized by HCl-assisted Cl₂ etching of silicon carbide and tungsten carbide powders. It is found that:During the series of CDC-Si C, the samples were mainly composed of compact amorphous carbon. A little curly ordered graphite occurred in the CDC-Si C synthesized at 1000 ?. With the increase of temperature, the amount of ordered graphite in CDC-Si C increased and the structure of CDC-Si C tended to be more ordered. All samples kept the bulk morphology of precursor. The composite structure of micropore-mesopore-macropore can be found in CDC-Si C. The pore size distribution was broad but the pore size distribution curves of CDC-Si C were similar which was synthesized by at different temperature. The products mainly contained mesoporous. The CDC-Si C-1000 obtained the highest specific surface area?2675m2/g? and the biggest pore volume?3.41 cm3/g?, and the specific surface area of the rest were similar, which were all above 1940 m2/g. CDC-Si C-1000 exhibited excellent reversibility and outstanding stability with the highest gravimetric capacitances?209.5 F/g?.During the series of CDC-WC, the samples were mainly composed of compact amorphous carbon. The curly ordered graphite structure at CDC-WC which prepared at 600-700 ? was noted, and curly stripe of graphene sheet occurred at CDC-WC-800 with 2-3 layers. With the temperature increased to 900 ?, the layers of graphite were not significantly increased, but increased in length of graphite,and the obvious graphite banded structure appeared. All samples kept the bulk morphology of precursor. The composite structure of micropore-mesopore-macropore can be found in CDC-WC. The pore size distribution was broad but the pore size distribution curves of CDC-WC were similar which was synthesized by at different temperature. The pore size of 1 nm can not appeared at CDC-WC-700. The CDC-WC-900 obtained the highest specific surface area? 2247 m2/g?, and the specific surface area of the rest were 2144 m2/g? CDC-WC-800?, 1917 m2/g? CDC-WC-600?, 1716 m2/g? CDC-WC-700?. CDC-WC-800 exhibited excellent reversibility and outstanding stability with the highest gravimetric capacitances? 148.2 F/g?.