Nanocolumnar titania thin films uniquely incorporated with carbon for visible light photocatalysis

Characterization of N,C-codoped TiO2 films prepared by reactive DC magnetron sputtering

“…The peak at 284.6 eV came from an adventitious elemental carbon. The peak intensity of carbonaceous species (C-C) decreased abruptly and a peak at 282 eV appeared after in situ Ar + etching of 10 s. However, no noticeable decrease in the peak intensity of the (C-C) component was observed until after a further etching of 180 s. This implied that some free carbons were present in the TiO 2 grain boundaries [13] acting as a photo sensitizer [46]. The C 1s peaks at 282.1 and 285.9 eV were obtained by deconvoluting the C 1s spectrum.…”

“…The preferential orientation shift has only been observed in TiO 2 films prepared by C-doping [13], and not in those prepared by anionic N-doping, S-doping [38] or N,S-codoping [22], nor in pure TiO 2 films that were prepared under similar deposition conditions [39,40]. For instance, the N-doped film had a typical (2 1 1)/(1 0 1) intensity ratio of 0.9, as presented in Table 1, indicating that Cdoping may have been the driving force of the nucleation of the preferential orientation shift.…”

“…Recently, Wong et al obtained a similar result, when they prepared C-covered and -doped TiO 2 films on 250 8C-heated Si and quartz substrates by reactive magnetron sputtering. They conclude that the sputtered carbons both substitutes the lattice oxygen atoms to form the Ti-C bond associated with a C 1s XPS peak at $281.8 eV [19] and are free graphitic nature (C-C), as revealed by the peak at 284.6 eV [13]. The former is regarded as Titanium dioxide film Hardness Sputtering Photocatalytic activity A B S T R A C T Titanium dioxide (TiO 2 ) films are deposited by codoping nitrogen and carbon on indium tin oxide-coated substrates as visible light (Vis)-enabled catalysts.…”

“…The practical applications of TiO 2 catalyst, however, are limited by its wide band gap of $3.2 eV, such that only the ultraviolet (UV) component (3-5%) of solar energy can be utilized. Among other potential modifications, such as RF plasma treatment [2], transition metal doping [3] and metal ionimplantation [4][5][6], in making visible light (Vis)-enabled catalysts, anionic dopants including nitrogen (N) [7][8][9][10][11], carbon (C) [12,13] or sulfur [14,15] as substitutes for oxygen in the TiO 2 lattice, are considered to be one of the most potentially effective methods. Asahi et al prepared TiO 2Àx N x films by sputtering TiO 2 targets for many hours in a 40% N 2 /Ar gas mixture and then annealing in nitrogen gas at 550 8C for 4 h to produce Vis (l = 436 nm) responsive catalysts [7].…”

Synthesis of TiO2 hollow spheres with tunable pore structure and enhanced photocatalytic activity

“…Doping and morphology control are considered as two very promising strategies. On one hand, it has been extensively demonstrated that anion-doping (such as nitrogen, sulfur and carbon) was an effective approach to improve the visible light photocatalytic activity of titania [5][6][7][8][9][10], and the same effect can also be obtained by doping of Ag [11], ZnO [12], and Ce [13], etc. On the other hand, it is well known that morphology and microstructures are very important to the photocatalytic activity of titania.…”