Abstract
Photocatalytic oxidation using semiconductors is one of the advanced oxidation processes for degradation of organic pollutants in water and air. TiO2 is an excellent photocatalyst that can mineralize a large range of organic pollutants such as pesticides and dyes. The main challenge is to improve the efficiency of the TiO2 photocatalyst and to extend TiO2 light absorption spectra to the visible region. A potential solution is to couple TiO2 with a narrow band gap semiconductor possessing a higher conduction band such as bismuth oxide. Therefore, here we prepared Bi2O3/TiO2 heterojunctions by the impregnation method with different Bi/Ti ratio. The prepared composites have been characterized by UV–Vis diffused reflectance spectra and X-ray diffraction. The photocatalytic activity of the heterojunction has been determined from the degradation of orange II under visible and UV light. Results show that Bi2O3/TiO2 heterojunctions are more effective than pure TiO2-anatase under UV-A irradiation, with an optimum for the Bi/Ti ratio of 5 %, for the photocatalytic degradation of Orange II. However, the photocatalytic activity under irradiation at λ higher than 420 nm is not much improved. Under UV–visible radiation, the two semiconductors are activated. We propose a mechanism explaining why our products are more effective under UV–visible irradiation. In this case the charge separation is enhanced because a part of photogenerated electrons from the conduction band of TiO2 will go to the conduction band of bismuth oxide. In this composite, titanium dioxide is the main photocatalyst, while bismuth oxide acts as adsorbent photosensitizer under visible light.
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References
Abe R, Takami H, Murakami N, Othani B (2008) Pristine simple oxides as visible light driven photocatalysts: highly efficient decomposition of organic compounds over platinum-loaded tungsten oxide. JACS 130:7780–7781
Ayekoe PY, Robert D, Gone DL (2015) TiO2/Bi2O3 photocatalysts for elimination of water contaminants. Part 1: synthesis of α- and β-Bi2O3 nanoparticles. Env Chem Lett 13:327–332
Bessekhouad Y, Robert D, Weber JV (2005) Photocatalytic activity of Cu2O/TiO2, Bi2O3/TiO2 and ZnMn2O4/TiO2 heterojunctions. Catal Today 101:315–321
Beydoun D, Amal R, Low G, McEvoy S (2002) Occurrence and prevention of photodissolution at the phase junction of magnetite and titanium dioxide. J Mol Catal A Chem 180:193–200
Bian ZF, Zhu J, Wang S, Cao Y, Qian X, Li H (2008) Self-assembly of active Bi2O3/TiO2 visible photocatalyst with ordered mesoporous structure and highly crystallized anatase. J Phys Chem C 111:6258–6262
Li D, Zhang Y, Zhang Y, Zhou X, Guo S (2013) Fabrication of bidirectionally doped Bi2O3/TiO2-NTs with enhanced photocatalysis under visible light irradiation. J Hazard Mater 258–259:42–49
Liu G, Wang L, Sun C, Yan X, Wang X, Chen Z, Smith SC, Cheng HM, Lu GQ (2009) Band-to-band visible-light photon excitation and photoactivity induced by homogeneous nitrogen doping in layered titanates. Chem Mater 21:1266–1274
LiuY XF, Wang F, Luo S, Yin X (2010) Synthesis, characterization, and activities of visible light-driven Bi2O3–TiO2 composite photocatalysts. J Alloys Compd 498:179–184
Malato S, Fernandez-Ibanez P, Maldonato MI, Blanco M, Gernjak W (2009) Decontamination and disinfection of water by solar photocatalysis: recent overview and trends. Catal Today 147:1–59
Mills A, Le Hunte S (1997) An overview of semiconductor photocatalysis. J Photochem Photobiol A Chem 108:1–35
Robert D (2007) Photosensitization of TiO2 by MxOy and MxSy nanoparticles for heterogeneous photocatalysis applications. Catal Today 122:20–26
Sammes NM, Tompsett GA, Näfe H, Aldinger F (1999) Bismuth based oxide electrolytes—structure and ionic conductivity. J Eur Ceram Soc 19:1801–1826
Serpone N, Borgarello E, Grâtzel M (1984) Visible light induced generation of hydrogen from H2S in mixed semiconductor dispersions: improved efficiency through inter-particle electron transfer. J Chem Soc Chem Commun (6):342–344
Serpone N, Marathamuthu P, Pichat P, Pelizzetti E, Hidaka H (1995) Exploiting the interparticle electron transfer process in the photocatalysed oxidation of phenol, 2-chlorophenol and pentachlorophenol: chemical evidence for electron and hole transfer between coupled semiconductors. J Photochem Photobiol A Chem 85:247
Vinodgopal K, Kamat PV (1995) Enhanced rates of photocatalytic degradation of an azo dye using SnO2/TiO2 coupled semiconductor thin films Environ. Sci Technol 29:841–845
Xiao X, Hu R, Liu C, Xing C, Qian C, Zuo X, Nan J, Wang L (2013) Facile large-scale synthesis of b-Bi2O3 nanosphere as a highly efficient photocatalyst for the degradation of acetaminophen under visible light irradiation 140–141, 433–443
Xu JJ, Ao YH, Fu DG, Yuan CW (2008) Synthesis of Bi2O3–TiO2 composite film with high photocatalytic activity under sunlight irradiation. Appl Surf Sci 255:2365–2369
Yang J, Li JT, Miao J (2011) Visible light photocatalytic performance of Bi2O3/TiO2 nanocomposite particles. Chin J Inorg Chem 27(3):547–555
Yang X, Lian X, Liu S, Jiang C, Tian J, Wang G, Chen J, Wang R (2013) Visible light photoelectrochemical properties of β-Bi2O3 nanoporous films: a study of the dependence on thermal treatment and film thickness. Appl Surf Sci 282:538–543
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The authors wish to thank the French Ministry of Foreign affairs and the Embassy of France in Ivory Coast (Campus France Program) for the PhD research Grant of Prisca AYEKOE.
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Ayekoe, P.Y., Robert, D. & Goné, D.L. Preparation of effective TiO2/Bi2O3 photocatalysts for water treatment. Environ Chem Lett 14, 387–393 (2016). https://doi.org/10.1007/s10311-016-0565-3
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DOI: https://doi.org/10.1007/s10311-016-0565-3