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

Abstract

Abstract:Highly crystallized C-doped mesoporous anatase TiO 2 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 TiO 2 nanocrystals with an average diameter about 10 nm, and pores are derived from spaces occupied by MWCNTs before removal. XRD characterization shows that TiO 2 is crystallized with a pure anatase phase. XPS characterization reveals that the relative carbon content in the TiO 2 is related to the duration of TiO 2 /MWCNT composite annealing before removal of MWCNT template. Three 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 TiO 2 .

Synthesis of NaOH-Modified TiOF2 and Its Enhanced Visible Light Photocatalytic Performance on RhB

“…The NaOH-modified TiOF2 has a raised adsorption plateau from 400 to 600 nm, which indicates stronger visible light absorption than that of TiOF2 (Figure 4a). Band gap estimation can be seen in Figure 4b showing that the band gap of NaOH-modified TiOF2 is 2.62 eV, which is lower than that of TiOF2 (2.80 eV) and lower than anatase TiO2 (3.2 eV) [1][2][3][4], NiO (4.0 eV) [6], and other oxides, indicating easier excitation by visible light. This can be explained in that NaOH treatment causes certain facet exposure and network morphologies of TiOF2, changing its light absorption properties.…”

“…In the past, TiO 2 has been widely used as a photocatalyst in the photo-degradation of organic pollutants. However, it has a wide energy band gap (3.1-3.2 eV) which only permit its UV light response and can easily cause electron-hole recombination [1][2][3][4]. Thus, studies on changing morphology [1][2][3], modification [1,4,5], and other methods were conducted to decrease its band gap or inhibit its electron-hole recombination.…”

“…However, it has a wide energy band gap (3.1-3.2 eV) which only permit its UV light response and can easily cause electron-hole recombination [1][2][3][4]. Thus, studies on changing morphology [1][2][3], modification [1,4,5], and other methods were conducted to decrease its band gap or inhibit its electron-hole recombination. The discovery of non-titanium semiconductor photocatalysts with a narrow intrinsic energy band gap, efficiently driven by visible light, may also attract much attention [5][6][7][8][9][10][11][12][13].…”

Effective Electron Transfer Pathway of the Ternary TiO2/RGO/Ag Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

“…However, there are still some defects mainly concentrated in the high recombination rate of photogenerated carriers and only absorbing UV light. The usual way for overcoming these shortcomings is coupling with sensitizing agents, narrow-bandgap semiconductor and non-metal-doping or with noble metal materials [9][10][11][12][13][14][15].…”

Effective Electrons Transfer Pathway of the Ternary TiO₂/RGO/Ag Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

“…The usual way for overcoming these shortcomings is coupling with sensitizing agents, narrow-bandgap semiconductor, and non-metal-doping or with noble metal materials. [7][8][9][10][11][12][13] Graphene, a promising material with the traits of large surface area, high conductivity, good transparency and high stability, has attracted great recent attention in various fields. [14][15][16] Combining TiO2 with graphene could enhance the photocatalytic capacity, which facilitates the charge separation and transportation and suppresses the recombination of photogenerated electrons and holes.…”