Mesostructured hollow spheres of graphitic N-doped carbon nanocast from spherica

2020-02-15 01:04:59

carbon materials silica Hollow spheres

责任者: Xia, Y.;Yang, Z.;Mokaya, R. 单位: Sch. of Chem., Nottingham Univ., UK 来源出处: Journal of Physical Chemistry B(J. Phys. Chem. B (USA)),2004/12/16,108(50):19293-8 摘要: Mesostructured hollow spheres of graphitic N-doped carbon (CNx) materials may be nanocast from solid core mesoporous silica SBA-15 spheres via a chemical vapor deposition (CVD) route. The hollow spheres are generated when the SBA-15 silica/carbon composite obtained after CVD is subjected to silica etching in hydrofluoric (HF) acid. Hollow spheres are only obtained for CVD temperatures above 900° C; here we present data on materials prepared at 1000° C. The use of acetonitrile as carbon precursor results in N-doped (CNx) materials with nitrogen content of ca. 6.5 wt %. The CNx hollow spheres prepared at 1000° C exhibit a high level of graphitization as evidenced by powder X-ray diffraction analysis and Raman spectroscopic studies. The CNx hollow spheres also exhibit good mesostructural ordering and have high surface area (779 m2/g) and pore volume (0.66 cm3/g). We propose a mechanism for the formation of the hollow spheres and clarify the importance of the CVD temperature in their formation 关键词: chemical vapour deposition;doping;etching;graphite;graphitisation;materials preparation;nitrogen;porous materials;powder technology;Raman spectra;silicon compounds;X-ray diffraction;mesostructured hollow spheres;graphitic nitrogen-doped carbon nanocast;solid core mesoporous silica SBA-15 spheres;chemical vapor deposition;SBA-15 silica-carbon composite;silica etching;hydrofluoric acid;HF;CVD temperatures;materials preparation;acetonitrile;graphitization;powder X-ray diffraction analysis;Raman spectroscopic studies;surface area;pore volume;1000 C;C:N;SiO2