Investigation of the anchoring silane coupling reagent effect in porphyrin sensitized mesoporous V-TiO 2 on the photodeg
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ORIGINAL PAPER
Investigation of the anchoring silane coupling reagent effect in porphyrin sensitized mesoporous V-TiO2 on the photodegradation efficiency of methyl orange under visible light irradiation Rahmatollah Rahimi • Masoumeh Mahjoub Moghaddas Solmaz Zargari
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Received: 6 September 2012 / Accepted: 28 December 2012 / Published online: 9 January 2013 Ó Springer Science+Business Media New York 2013
Abstract In order to efficient utilization of visible light in the photodegradation reaction, mesoporous vanadium doped TiO2 (V-TiO2) particles sensitized by tetrakis (4-carboxyphenyl)porphyrin (TCPP) dyes were synthesized, and characterized. For investigation of the anchoring coupling between porphyrin and TiO2 surface, two photocatalyst containing ester-like linkage (TCPP–V-TiO2) and amide-like linkage (TCPP–NH2–V-TiO2) were compared in the photodegradation of methyl orange (MO) aqueous solution. It was found that the photocatalytic activity of the TCPP–V-TiO2 was higher than TCPP–NH2–V-TiO2 (95 % compared to 62 %). Importantly, TCPP–V-TiO2 was particularly stable in the visible light photocatalytic activity after six cycles. Keywords Porphyrin Mesoporous V-TiO2 Silane coupling reagent Visible light photocatalysis
1 Introduction Photocatalysis is a green technology to decrease organic pollutants in wastewater which has considered as a promising approach for pollution abatement and recovering of wastewater [1, 2]. Many studies have been reported that numerous organic pollutants can be decomposed completely through photocatalysis using metal oxide semiconductor nanostructure under UV light irradiation [3–6]. Because only around 4 % of the solar spectrum occupies with the UV region [7], various high performance visible R. Rahimi (&) M. M. Moghaddas S. Zargari Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114, Iran e-mail: [email protected]; [email protected]
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light photocatalysts have been developed [8–10]. Mesoporous TiO2 with ordered pores is among the best candidates as a host matrix constituting composite photocatalysts because of their homogenous nanometer-sized pores and the large surface area [11, 12]. The mesoporous structure of TiO2 forms large pore channels and constructs pore opening more accessible and, then, improves the diffusivity of reactants and products within the system and increases the availability of the internal surface [13]. Recently, it has become a hot question how to increase the visible light photocatalytic activity of TiO2. The metal doped TiO2 and the sensitization of TiO2 with dye molecules are effective approaches used to increase the visible light photocatalytic activity of samples [14–16]. Reforming of TiO2 through vanadium doping is promising method due to visible light region extension and the fast separation efficiency of electron–hole pairs [17, 18]. The sensitization of TiO2 by porphyrin dyes is also considered as an effective approach to improve visible spectral absorption and photocatalytic activity under vi
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