Papers by Keyword: Visible-Light Response

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Authors: Tomoko Yoshida, Shunsuke Muto, Jun Wakabayashi
Abstract: Energetic nitrogen ion was injected into a TiO2 photocatalyst in order to investigate the optimal local concentration of doped nitrogen for visible-light response. N+-implanted TiO2 samples promoted the photocatalytic activity under visible-light irradiation. N K-edge XANES of the highest activity sample indicated that N replaces the O sites near the surface, whereas in the samples of higher N+ fluence, N−O and/or N−N species formed. Depth-resolved N K-edge ELNES revealed the two types of N, depending on the concentration, and we found the local N concentration effective for visible-light response was less than ∼1 at%. Further, the spatial distributions of the different chemical states of N by energy-filtering TEM (FETEM) supported these findings.
Authors: Ryo Niishiro, Akihiko Kudo
Abstract: This review paper represents photocatalytic properties of metal cation-doped TiO2 (rutile) and SrTiO3 photocatalysts for O2 evolution from an aqueous silver nitrate solution and H2 evolution from an aqueous methanol solution under visible light irradiation. Photocatalytic activities for the O2 evolution of Cr/Sb and Rh/Sb-codoped TiO2 are strongly dependent on the codoping ratio and the amount of doped chromium and rhodium. The codopant controls the oxidation number of doped chromium and rhodium. Rh-doped SrTiO3 in which the doped Rh species possesses a reversible redox property is active for the H2 evolution reaction under visible light irradiation. Overall water splitting under visible light irradiation proceeds with Z-scheme photocatalyst systems consisting of the Rh-doped SrTiO3 as a H2 evolution photocatalyst combined with BiVO4 as an O2 evolution photocatalyst and an Fe3+/Fe2+ electron mediator.
Authors: Yun Hu, Xia Zhang, Chao Hai Wei
Abstract: Visible-light responsible Mn-N-codoped TiO2 nanocrystal photocatalysts were synthesized for the first time by a simple hydrothermal synthesis method. X-ray powder diffraction (XRD) measurement indicated that all of the photocatalysts have an anatase crystallite structure and the increase of the doping concentration had less effect on the structure and particle size. Comparing to N-doped TiO2, a shift of the absorption edge of Mn-N-codoped TiO2 to a lower energy and a stronger absorption in the visible light region were observed. The Mn-N-codoped TiO2 showed a higher photocatalytic reactivity than undoped TiO2 and N-doped TiO2 for the photodegradation of rhodamine B (RhB) under visible light irradiation. The doping concentration had an optimal value, according to the highest photocatalytic activity. This suggested that Mn and N codoping has important effects on the improvement of visible-light responsible photocatalytic activity.
Authors: Yong Bo Lin, Si Yao Guo, Feng Fei Wang, Cheng Hui Zeng, Na Jiang, Bo Song, Yong Sun
Abstract: In this paper, the degradation of organophosphorus pesticide by nitrogen and sulfur codoped TiO2 photocatalysts under iodine-tungsten lamp irradiation has been investigated. And we adjusted the concentration of nitrogen to see the change of particle size of nitrogen and sulfur codoping TiO2. According to the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), the different concentration of N, S codoping under different calcination temperature was discussed. N, S codoped TiO2 sample has a smaller particle size at a low anneal temperature than the one at high anneal temperature.
Authors: Koichiro Tsujimaru, Masakazu Anpo
Abstract: Advanced ion-beam techniques such as metal ion-implantation and RF magnetron sputtering deposition were successfully applied in the development of titanium oxide photocatalysts capable of absorbing and working under both UV and visible light irradiation. This advanced physical method was found to be one of the most promising approaches to preparation of highly functional second-generation titanium oxide-based photocatalytic materials, TiO2 nano-powders, highly dispersed titanium oxide species within zeolite frameworks, and TiO2 thin film systems with efficient solar beam utilization of up to 20-30 %.
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