Chem. Mater. 2005, 17, 1553-1560
1553
Generalized and Facile Synthesis Approach to N-Doped Highly Graphitic Mesoporous Carbon Materials Yongde Xia and Robert Mokaya* School of Chemistry, UniVersity of Nottingham, UniVersity Park, Nottingham, NG7 2RD, United Kingdom ReceiVed NoVember 5, 2004. ReVised Manuscript ReceiVed January 14, 2005
The synthesis and characterization of porous graphitic carbon materials via chemical vapor deposition (CVD) using various mesoporous silicas including SBA-12, SBA-15, MCM-48, MCM-41, and HMS as solid templates is presented. The use of acetonitrile as carbon precursor generates N-doped carbon (CNx type) materials with nitrogen content of ca. 8 wt %. The N-doped carbon materials exhibit both wellordered mesoporosity and high levels of graphitic character. The mesostructural ordering and extent of graphitization depend on the CVD (i.e., carbonization) temperature and the nature of the silica template. In general, higher CVD temperatures (>900 °C) generated high levels of graphitic character but compromised the mesostructural ordering of the carbon materials. The mesostructural ordering of the CNx materials (and replication of pore channel ordering from the silica template) depends on the nature of the mesoporous silica used as solid template. We achieved structural replication and high surface area (440-1000 m2/g) CNx materials from SBA-12, MCM-48, and SBA-15 silica templates. MCM-41 and HMS silicas did not function effectively as templates and generated low surface area (1000 °C) results in highly graphitic CNx materials but with slightly compromised mesostructural ordering. The mesostructural ordering of the CNx materials (i.e., whether the structural ordering of the silica template is replicated in the carbon) depends on the nature of the mesoporous silica template. We achieved structural replication for SBA-12, MCM-48, and SBA-15 silicas, while MCM41 and HMS silicas did not function effectively as solid templates. The presence of Na ions in the mesoporous silicas was inimical to the formation of mesostructured carbon materials. Acknowledgment. This work was funded by the EPSRC. The authors are grateful to Prof. M. George for assistance with Raman spectroscopy. Supporting Information Available: Representative SEM images of various mesoporous silica templates and corresponding mesoporous carbon materials. Powder XRD patterns of carbon materials (PDF). This material is available free of charge via the Internet at http://pubs.acs.org. CM048057Y
