Photocatalytic decomposition of halogenated organics over nanocrystalline titania

Wang, Chen‐Chi; Zhang, Zhibo; Ying, Jackie Y.

doi:10.1016/s0965-9773(97)00130-x

Cited by 184 publications

(82 citation statements)

References 3 publications

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“…If so, then it is possible that they may be sufficiently small to exhibit the quantum confinement size effect, which could be expected to increase their photocatalytic performance significantly [76][77][78][79]. For photocatalytic TiO 2 , this has been suggested to result in a fourfold increase in performance [76,[80][81][82][83].…”

Section: Discussionmentioning

confidence: 99%

Aqueous and Surface Chemistries of Photocatalytic Fe-Doped CeO2 Nanoparticles

et al. 2017

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Abstract:The present work describes the effects of water on Fe-doped nanoparticulate CeO 2 , produced by flame spray pyrolysis, which represent a critical environmental issue because CeO 2 is not stable in typical atmospheric conditions. It is hygroscopic and absorbs~29 wt % water in the bulk when exposed to water vapor but, more importantly, it forms a hydrated and passivating surface layer when immersed in liquid water. In the latter case, CeO 2 initially undergoes direct and/or reductive dissolution, followed by the establishment of a passivating layer calculated to consist of~69 mol % solid CeO 2 ·2H 2 O and~30 mol % gelled Ce(OH) 4 . Under static flow conditions, a saturated boundary layer also forms but, under turbulent flow conditions, this is removed. While the passivating hydrated surface layer, which is coherent probably owing to the continuous Ce(OH) 4 gel, would be expected to eliminate the photoactivity, this does not occur. This apparent anomaly is explained by the calculation of (a) the thermodynamic stability diagrams for Ce and Fe; (b) the speciation diagrams for the Ce 4+ -H 2 O, Ce 3+ -H 2 O, Fe 3+ -H 2 O, and Fe 2+ -H 2 O systems; and (c) the Pourbaix diagrams for the Ce-H 2 O and Fe-H 2 O systems. Furthermore, consideration of the probable effects of the localized chemical and redox equilibria owing to the establishment of a very low pH (<0) at the liquid-solid interface also is important to the interpretation of the phenomena. These factors highlight the critical importance of the establishment of the passivating surface layer and its role in photocatalysis. A model for the mechanism of photocatalysis by the CeO 2 component of the hydrated phase CeO 2 ·2H 2 O is proposed, explaining the observation of the retention of photocatalysis following the apparent alteration of the surface of CeO 2 upon hydration. The model involves the generation of charge carriers at the outer surface of the hydrated surface layer, followed by the formation of radicals, which decompose organic species that have diffused through the boundary layer, if present.

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Section: Discussionmentioning

confidence: 99%

Aqueous and Surface Chemistries of Photocatalytic Fe-Doped CeO2 Nanoparticles

et al. 2017

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“…However, since the photo-oxidation of aromatic compounds on P25 TiO 2 is not sufficiently fast, a more active catalyst must be formulated. It has been shown that the size of TiO 2 particles affects its catalytic activity [10][11][12][13][14][15][16]. The structural and electronic properties of the TiO 2 catalyst can undergo significant changes as the particle size decreases, as the proportions of planar, edge and corner sites changes as the size of catalyst become smaller.…”

Section: Introductionmentioning

confidence: 99%

Gas-phase photo-oxidation of toluene using nanometer-size TiO2 catalysts

Maira

Yeung

Soria

et al. 2001

Applied Catalysis B: Environmental

223

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“…Synthesis of TiO 2 anatase nanocrystals has been achieved by several methods including impregnation (4), coprecipitation (5), sol-gel (6)(7)(8), hydrothermal method (9-11), and chemical vapor deposition (CVD) (12,13). In our study, a metallorganic CVD (MOCVD) process was used to prepare TiO 2 nanoparticles.…”

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confidence: 99%