Efficient Degradation of 4-Nitrophenol by Using Functionalized Porphyrin TiO2 Photocatalysts Under Visible Irradiation
01 Jan 2007-
TL;DR: In this article, the photocatalytic activity of polycrystalline TiO2 samples impregnated with H2Pp(a), H2pp(b), CuPp (a), and CuPm(b) as sensitizers has been investigated by carrying out the photo-degradation of 4-nitrophenol (4-NP) as a probe reaction in aqueous suspension and under visible light.
Abstract: The novel porphyrins 5,10,15,20-tetra-[4-(3-phenoxy)-propoxy]phenyl porphyrin, H2Pp(a) and 5,10,15,20-tetra-[2-(3-phenoxy)-propoxy]phenyl porphyrin, H2Pp(b) and their corresponding copper(II) complexes CuPp(a), CuPp(b) were synthesized and characterized by using various spectroscopic techniques. The photocatalytic activity of polycrystalline TiO2 samples impregnated with H2Pp(a), H2Pp(b), CuPp(a) and CuPp(b) as sensitizers have been investigated by carrying out the photo-degradation of 4-nitrophenol (4-NP) as a probe reaction in aqueous suspension and under visible light. The maximum photocatalytic activity was obtained using TiO2 loaded with a monolayer of the copper porphyrin CuPp(b) in the amount of 18 μmol per gram of TiO2. The photocatalytic efficiency decreased in the following order: TiO2-CuPp(b), TiO2-CuPp(a), TiO2-H2Pp(b), TiO2-H2Pp(a). A possible mechanism of the photocatalytic degradation is also proposed.
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TL;DR: In this article, the degradation capacity and mechanism of Fe/Cu bimetallic system with different theoretical copper mass loadings were characterized by SEM, EDS, XRD and laser particle size analyzer.
Abstract: In this study, in order to further investigate the degradation capacity and mechanism of Fe/Cu bimetallic system, the prepared Fe/Cu bimetallic particles with different theoretical copper mass loadings (0.05, 0.11, 0.24, 0.41, 0.62, 0.89, 1.26 and 1.81 g Cu/g Fe) were characterized by SEM, EDS, XRD and laser particle size analyzer. Also, the effect of theoretical Cu mass loading and five key operating parameters on the PNP removal efficiency was investigated thoroughly. Furthermore, the mineralization process of PNP was studied by using COD, TOC, UV–vis spectra, FTIR spectra and GC/MS. The results show that a large number of fine Cu particles were produced from the excessive theoretical Cu mass loading, and they facilitated the catalytic reactivity of the Fe/Cu bimetallic particles at Cu loading
202 citations
TL;DR: In this article, a review of the use of dye-sensitized nanoparticles (NPs) for heterogeneous photocatalysis related to water purification is considered, which covers the impact of several parameters on the photodegradation performances of various pollutants.
175 citations
TL;DR: In this article, the photocatalytic activity of tetra(4-carboxyphenyl)porphyrin with different metal centers (Fe(III), Cu(II), Zn(II) and metal-free), adsorbed on TiO 2 surface has been investigated by carrying out the photodegradation of atrazine in aqueous solution and under visible light irradiation.
Abstract: The photocatalytic activity of tetra(4-carboxyphenyl)porphyrin with different metal centers (Fe(III), Cu(II), Zn(II) and metal-free), adsorbed on TiO 2 surface has been investigated by carrying out the photodegradation of atrazine in aqueous solution and under visible light irradiation Under this condition, no photocatalytic activity was found meaning that anion superoxide (which was evidenced by photodegradation of luminol) is not sufficiently oxidant to degrade atrazine However by adding hydrogen peroxide in the solution, a degradation of atrazine was observed Under this condition, the maximum photocatalytic activity was obtained using Cu(II) porphyrin as photosensitizer (82% of degradation after 1 h of irradiation) The influence of H 2 O 2 concentration has been studied It has been found that in the range 0015–005 mol L −1 the higher the concentration the higher the rate of degradation, whereas for higher H 2 O 2 concentrations, the rate of degradation leveled off Intermediate products were identified using high performance liquid chromatography-Diode Array Detector (HPLC-DAD) and GC–MS and a mechanism of degradation was proposed
146 citations
TL;DR: In this paper, the photooxidation of oxalic acid, catalyzed by nanosized TiO2 or WO3 and composite photocatalysts, was studied under irradiation with UV, visible and combined UV-visible light.
Abstract: The photooxidation of oxalic acid, catalyzed by nanosized TiO2 or WO3 and composite photocatalysts: Au/TiO2, Au/WO3, WO3/TiO2, Au/WO3/TiO2 was studied under irradiation with UV, visible and combined UV–visible light. The catalysts were characterized by the XRD, XPS, SEM and TEM methods. The photocatalytic mineralization of oxalic acid, catalyzed by WO3/TiO2 or Au/WO3/TiO2, proceeded at a significantly higher rate under UV-A irradiation than that under visible light. This is due to the lower specific surface area of the WO3 and its small amount in the composite catalyst. Doping of the semiconductor materials with gold nanoparticles more than doubles the rates of mineralization of oxalic acid, compared to the un-doped samples, and more significantly in the case of Au/WO3/TiO2. The higher rate constants of oxalic acid decomposition under UV, visible or UV–visible light irradiation with the WO3/TiO2 and Au/WO3/TiO2 catalysts, compared with those measured with the individual oxide photocatalysts, are due to the more efficient separation of the electron–hole charges generated upon irradiation. Especially efficient is the charge separation in the case of the Au/WO3/TiO2 photocatalyst under irradiation with UV or combined UV–visible light, when the rate constants of oxalic acid destruction are approximately 1.7 times higher than that of the process catalyzed by Au/TiO2 and 3 times higher than that catalyzed by pure TiO2.
143 citations
TL;DR: Thin films of meso-tetra(4-carboxyphenyl)porphyrinato copper(II) (CuTCPP) in conjunction with anatase TiO2 have been formed on cotton fabric and showed superior self-cleaning performance when compared to bareTiO2-coated cotton.
Abstract: Thin films of meso-tetra(4-carboxyphenyl)porphyrinato copper(II) (CuTCPP) in conjunction with anatase TiO2 have been formed on cotton fabric. Their self-cleaning properties have been investigated by conducting photocatalytic degradation of methylene blue, coffee and wine stains under visible-light irradiation. CuTCPP/TiO2-coated cotton fabrics showed superior self-cleaning performance when compared to bare TiO2-coated cotton. Furthermore, CuTCPP/TiO2-coated fabrics showed significant photostability under visible-light as compared to free base TCPP/TiO2-coated fabrics. The fabrics were characterized by FESEM, XRD and UV–vis spectroscopy. An insight into the mechanistic aspects of the CuTCPP/TiO2 photocatalysis is also discussed. Visible-light driven self-cleaning cotton based on copper(II) porphyrin/TiO2 catalyst exhibits significant potential in terms of stability and reproducibility for self-cleaning applications.
135 citations
References
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01 Jan 2002
TL;DR: In this article, the Iron and Cobalt Pigments: Biosynthesis, Structure and Degradation Volume 11: Bioinorganic and Bioorganic Chemistry Volume 12: The iron and cobalt pigments and chlorophylls and Bilins: Bioinorganic, bioorganic, and bioorganic chemistry Volume 14: Medical Aspects of Porphyrins Volume 15: Phthalocyanines: Synthesis Volume 16: PHTHC: Spectroscopic and Electrochemical Characterization Volume 17: PhTHCINE Properties and Materials Volume 18: Multiporph
Abstract: Volume 11: Bioinorganic and Bioorganic Chemistry Volume 12: The Iron and Cobalt Pigments: Biosynthesis, Structure and Degradation Volume 13: Chlorophylls and Bilins: Biosynthesis, Synthesis and Degradation Volume 14: Medical Aspects of Porphyrins Volume 15: Phthalocyanines: Synthesis Volume 16: Phthalocyanines: Spectroscopic and Electrochemical Characterization Volume 17: Phthalocyanines Properties and Materials Volume 18: Multiporphyrins, Multiphthalocyanines and Arrays Volume 19: Applications of Phthalocyanines Volume 20: Phthalocyanines: Structural Characterization
3,018 citations
TL;DR: In this paper, the preparation of highly reactive titanium oxide photocatalysts and the clarification of the active sites as well as the detection of the reaction intermediates at the molecular level are discussed.
1,554 citations
TL;DR: In this article, a new synthetic strategy for preparing tetraphenylporphyrins is presented, which should greatly expand synthetic entries into porphyrin-containing model systems, and is complementary to the Adler-Longo procedure.
Abstract: We present a new synthetic strategy for preparing tetraphenylporphyrins that should greatly expand synthetic entries into porphyrin containing model systems. Pyrrole and the desired benzaldehyde react reversibly at room temperature with trace acid catalysis to form the cyclic tetraphenylporphyrinogen at thermodynamic equilibrium. An oxidant is then added to irreversibly convert the porphyrinogen to the porphyrin. The greater stability of the cyclic porphyrinogen over the open-chain polypyrrylmethanes occurs when the reaction is performed at moderate dilution (10-2 M). The reaction at high dilution or high concentration affords a negligible yield of the cyclic porphyrinogen. Porphyrinogen exchange reactions provide proof of equilibrium. This methodology is complementary to the Adler-Longo procedure, allowing small quantities of porphyrins to be prepared from sensitive aldehydes in 30-40% yield without difficult purification problems. This methodology is also extended to the preparation of meso-tetraalkylporphyrins and one hybrid porphyrin containing both aryl and alkyl substituents. The mild reaction conditions and convenience of this method permit consideration of new design strategies in preparing complex porphyrins.
1,298 citations
TL;DR: The study demonstrates that the modification of TiO2 both to extend its spectral response to the visible region and to improve its catalytic efficiency can be achieved by doping with boron, a nonmetal, and Ni2O3, a metal oxide.
Abstract: To promote efficient use of solar energy, many studies have focused on the modification of TiO2 to extend its spectral response to visible region. Here we report a combined modification of TiO2 by two components: the nonmetal element boron and the metal oxide Ni2O3. The photocatalyst presents high photocatalytic activity in the visible region, which can efficiently degrade and mineralize toxic organic pollutants such as trichlorophenol (TCP), 2,4-dichlorophenol (2,4-DCP), and sodium benzoate. The dechlorination and mineralization results indicate the photocatalytic pathway via visible light excitation. The study demonstrates that the modification of TiO2 both to extend its spectral response to the visible region and to improve its catalytic efficiency can be achieved by doping with boron, a nonmetal, and Ni2O3, a metal oxide.
1,097 citations
TL;DR: In this paper, the photocatalytic water splitting on Cu2O powder proceeds without any noticeable decrease in the activity for more than 1900 h. The authors investigated the decomposition of water into H2 and O2 under visible light irradiation.
792 citations