Combinatorial Discovery of New Photocatalysts for Water Purification with Visible Light

Abstract

Doped with up to 70 different metal salts, three semiconductor oxides (TiO2, SnO2, and WO3) formed the basis of three libraries of mixed oxides. From a high‐throughput method, over 30 oxides were found to have activities similar to the well‐studied Pt‐doped TiO2 towards the catalyzed decomposition of a model pollutant 4‐chlorophenol in water on irradiation with visible light. Two of the new materials (Ir‐doped WO3 and Ce‐doped SnO2) have been reproduced by conventional synthesis, and their catalytic activity was confirmed.

How the Dyes Are Degraded/Mineralized in a Photocatalytic System? The Possible Role of Auxochromes

“…Oxidation technologies that lead to either complete mineralization or transformation to less toxic oxygenate have gathered considerable attention for the elimination of dyes in the recent years (Chong et al 2010;Ligrini et al 1993;Rauf and Ashraf 2009). Photocatalysis, being the part of oxidation technologies, is considered as s solution provider for the cost-effective removal of dyes from an industrial effluent (Hernández-Alonso et al 2009;Fujishima et al 2000;Jiuhui 2008;Bhatkhande et al 2002;Lettmann et al 2001;Lazar et al 2012;Mills et al 1993) where the conversion of light energy into chemical energy by the semiconductor nontoxic materials, with the in situ generation of oxidizing species, leads to the complete mineralization of dyes (Sotto et al 2010;Ahmed et al 2010). Since carried out at ambient conditions, photocatalytic processes do not require extreme operational conditions of pressure and temperature or addition of expensive oxidizing agents for the generation of oxidizing species (Chatterjee and Dasgupta 2005;Lam et al 2012;Hameed et al 2011;Neppolian et al 2003).…”

Visible-light photoconductivity of Zn1−xCoxO and its dependence onCoJohnson1, Cohn2, Kaspar3 et al. 2011Phys. Rev. B385391View full textAdd to dashboardCite

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Mid-gap photoactivity is usually associated with donor-or acceptor-type photoionization (or charge-transfer) transitions of the added impurity ions. Such transitions can generate one band-like charge carrier (either a conduction-band electron or a valence-band hole) by formal charge transfer from or to the impurity.…”

Photocatalytic behavior of silver vanadates: Microemulsion synthesis and post-reaction characterization

“…Thus, its potential as a sustainable technology cannot be entirely fulfilled, limiting its industrial applications. However, in the last years, many researches are looking for other semiconductors susceptible to undergo photoinduction in the visible region, such as other oxides (Fe 2 O 3 , SnO, WO 3 ), mixed oxides, metalates, nitrides and chalcogenides, or even cation interchanged zeolites and pillared clays [1][2][3]. The design of visible-driven photocatalysts involves the band gap reduction of the well-known semiconductors that are active using UV light.…”

“…In this sense, different metallates have been evaluated as promising photocatalysts for visible light absorption [1]. These materials are metal oxides with d 0 transition metals and ns 2 cations, and with lower band gap values capable of generating charge carriers to be involved in redox reactions [2,3,5]. However, these semiconductors have some disadvantages, such as poor textural properties, structural heterogeneity and high particle size, mainly caused by the synthesis procedures conventionally employed.…”