Highly Crystallized C-Doped Mesoporous Anatase TiO2 with Visible Light Photocatalytic Activity

Abstract

Highly crystallized C-doped mesoporous anatase TiO2 is prepared using a multi-walled carbon nanotube (MWCNT) mat as both a “rigid” pore template and a carbon doping source. SEM and TEM characterization shows that the MWCNT template imposed a pore structure in reverse of that of the MWCNT mat. The pore walls are formed by chain-like interconnected TiO2 nanocrystals with an average diameter about 10 nm, and pores are derived from spaces occupied by MWCNTs before removal. XRD characterization shows that TiO2 is crystallized with a pure anatase phase. XPS characterization reveals that the relative carbon content in the TiO2 is related to the duration of TiO2/MWCNT composite annealing before removal of MWCNT template. Three samples prepared contain 2.3%, 2.8% and 3.9% carbon; show a ~30 nm red shift and a plateau of adsorption from 450–800 nm in UV–Vis spectra in comparison to that of P25; and display visible light photocatalytic activity for decomposition of methyl orange (MO) in relationship with the carbon content and crystallinity of the anatase TiO2.