Effect of platinum on the photocatalytic degradation of chlorinated organic compound

doi:10.1016/S1001-0742(10)60480-9

Journal of Environmental Sciences

Volume 23, Issue 4, April 2011, Pages 687-692

https://doi.org/10.1016/S1001-0742(10)60480-9 Get rights and content

Abstract

TiO₂ nanoparticles, doped with different Pt contents, were prepared by a modified photodeposition method using Degussa P-25 TiO₂, H₂PtCl₆·6H₂O and methanol as the solvents. The physicochemical properties of Pt/TiO₂ were investigated by the nitrogen adsorption and desorption isotherm measurement technique, X-ray diffraction analysis and photoluminescence spectra, respectively. Reaction rates from photocatalytic removal of dichloromethane over Degussa P-25 TiO₂ and Pt/TiO₂ were evaluated. The average diameter and BET surface area of the TiO₂ catalyst particles were 300 nm and 50 m²/g, respectively. The degradation efficiency was 99.0%, 82.7%, 55.2%, and 57.9% with TiO₂ at inlet concentrations of 50, 100, 200, and 300 ppm, respectively. And the degradation efficiency was 99.3%, 79.7%, 76.5%, and 73.4% with a 0.005 wt.% Pt/TiO₂ at inlet concentrations of 50, 100, 200, and 300 ppm, respectively. In addition, we found that the photoluminescence emission peak intensities decreased with increases in the doping amount of Pt, which indicates that the irradiative recombination was weakened. Furthermore, the results showed that the UV/0.005 wt.% Pt/TiO₂ process was capable of efficiently decomposing gaseous DCM in air.

References (22)

HW Chen et al.
Effect of Pt/TiO₂ characteristics on temporal behavior of o-cresol decomposition by visible light-induced photocatalysis
Water Research
(2007)
Y Ishibai et al.
Synthesis of visible-light active TiO₂ photocatalyst with Ptmodification: Role of TiO₂ substrate for high photocatalytic activity
Applied Catalysis B: Environmental
(2008)
XZ Li et al.
Photoelectrocatalytic degradation of humic acid in aqueous solution using a Ti/TiO₂ mesh photoelectrode
Water Research
(2002)
Y Ku et al.
Decomposition of gaseous trichloroethylene in a photoreactor with TiO₂-coated non-woven fiber textile
Applied Catalysis B: Environmental
(2001)
Y Luo et al.
Heterogeneous photocatalytic oxidation of trichloroethylene and toluene mixtures in air: kinetic promotion and inhibition, time-dependent catalyst activity
Journal catalyts
(1996)
J Mo et al.
Photocatalytic purification of volatile organic compounds in indoor air: A literature review
Atmospheric Environment
(2009)
MM Rahman et al.
Optical properties and X-ray photoelectron spectroscopic study of pure and Pb-doped TiO₂ thin films
Journal of Physics and Chemistry of Solids
(1999)
S Sakthivel et al.
Enhancement of photocatalytic activity by metal deposition: characterisation and photonic efficiency of Pt, Au and Pd deposited on TiO₂ catalyst
Water Research
(2004)
T Sreethawong et al.
Synthesis, characterization, and photocatalytic activity for hydrogen evolution of nanocrystalline mesoporous titania prepared by surfactant-assisted templating sol-gel process
Journal of Solid State Chemistry
(2005)
WY Teoh et al.
Inter-relationship between Pt oxidation states on TiO₂ and the photocatalytic mineralization of organic matters
Journal of Catalysis
(2007)

CG Wu et al.

Enhancement of the photo catalytic performance of TiO₂ catalysts via transition metal modification

Catalysis Today

(2004)

Cited by (11)

Synergistic effect of nano-floret CeO<inf>2</inf>/ZnO nanocomposite as an efficient photocatalyst for environmental remediation
2024, Ceramics International
In this study, pure CeO₂, ZnO, and CeO₂/ZnO nanocomposite (CZ-NC) were synthesized using solution combustion method using urea as a fuel. The physical properties of the as-prepared samples were investigated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, photoluminescence (PL) spectroscopy, Raman spectroscopy, and Brunauer-Emmett-Teller (BET) analysis. X-ray diffraction peak confirmed the successful fabrication and structural parameters of the nanomaterials. FTIR and Raman analyses confirmed the presence of Ce–O and Zn–O vibrational modes, respectively. The energy band gap (E_g) of CZ-NC estimated from the UV–vis spectra has narrowed to 1.88 eV, which enhanced the photocatalytic activity. The weak PL intensity peaks implied a lower charge recombination rate with maximum charge separation, facilitating more radical generation. BET analysis has confirmed the nanomaterial's large surface area and mesoporous nature. FESEM was used to investigate the surface morphologies of the nanomaterials, which displayed beautiful florets and sheet morphologies for CZ-NC. The internal structure of the nanomaterials was analyzed using HRTEM. EDAX further confirmed the purity of the nanomaterials, and homogeneous dispersion of elements was observed by EDX mapping. Antibacterial and dye-degradation experiments were conducted to understand the photocatalytic activities of the samples. The antibacterial activity of CZ-NC against both gram-positive and gram-negative bacteria was superior to that of pure nanoparticles. Methylene blue (MB) dye was used to evaluate the degradation efficiency. The maximum degradation efficiency of 97.10 % was achieved for CZ-NC under a visible light source for 120 min. This enhanced activity can be attributed to the Advanced Oxidation Process (AOP).
Visible light induced photodegradation of chlorinated organic pollutants using highly efficient magnetic Fe<inf>3</inf>O<inf>4</inf>/TiO<inf>2</inf> nanocomposite
2021, Optik
Citation Excerpt :
Degussa P-25 TiO2 (anatase 80%, rutile 20% and particle size 25 ± 5) presents high photocatalytic ability to degrade adsorbed pollutants. But the easy separation of photocatalysts after treatment, complete recovery and efficient reusability is infeasible with this process [18,21,22]. To overcome this limitation and to further enhance the performance of TiO2 the doping of metal/ metalloids or mixing with metal oxides of different bandgaps is an effective approach.
Herein, iron oxide/titanium oxide nanocomposite (Fe₃O₄/TiO₂) has been synthesized via an ultrasonic-assisted co-precipitation method. The synthesized nanocomposite has been characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), vibrating sample magnetometer (VSM), Fourier-transform infrared spectroscopy (FTIR), photoluminescence spectra, photocurrent response, and UV-Visible spectroscopy. The nanocomposite exhibited magnetic property with a saturation magnetization of 16.02 emu/g. The synergetic effect of magnetite and titanium oxide makes the nanocomposite highly efficient, stable and reusable for water remediation applications. The higher photocurrent response confirms more charge separation, which is responsible for the enhanced photocatalytic activity. Nanocomposite showed superior photocatalytic ability (~100%) than P-25 TiO₂ (20% and 22%) to degrade the chlorinated organic pollutants like 2,4-dichlorophenol (2,4-DCP) and chlorobenzene (CB) respectively under visible irradiation within 50 min. The optimum performance has been achieved at pH 5 using 100 mg/L Fe₃O₄/TiO₂ nanocomposite with 98% of reusability. The kinetics of photodegradation of 2,4-DCP and CB under visible irradiation of magnetic Fe₃O₄/TiO₂ nanocomposite is well fitted with first-order reaction. A facile synthesis method, outstanding photocatalytic activity under visible as well as sunlight, synergistic effect between Fe₃O₄ and TiO₂ and easy separation for reusability makes the nanocomposite a prospective material towards environmental remediation and solar energy harvesting.
Enhanced photocatalytic activity of Pt-doped TiO<inf>2</inf> for NO<inf>x</inf> oxidation both under UV and visible light irradiation: A synergistic effect of lattice Pt<sup>4+</sup> and surface PtO
2015, Chemical Engineering Journal
Citation Excerpt :
Lin et al. [22] reported that platinum (Pt) modified TiO2 exhibited higher photocatalytic activity than TiO2 for NOx oxidation and the Pt modification enhanced the further oxidation of NO2 to NO3−. However, nearly all the reported noble metal modifications to TiO2 are surface modification, such as impregnation and ultraviolet (UV) deposition, which only improves the UV light driven photocatalytic activity or only improves the visible light driven activity while the UV light driven activity remains the same or even decreases [23–26]. In the present work, we prepared a Pt doped TiO2 with Pt4+ species in the lattice and PtO species on the surface of TiO2 simultaneously synthesized by a sol–gel method.
Various platinum doped TiO₂ with different doping ratios was successfully synthesized by a facile sol–gel method. The structural and optical properties of as-synthesized samples were characterized by the X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and UV–vis diffuse reflectance spectroscopy (DRS). The results showed that all samples were anatase crystals and showed extended absorption into visible light region. The Pt states in the samples were investigated by energy dispersive spectrometer (EDS) and X-ray photoelectron spectra (XPS) analyses. The results revealed that Pt⁴⁺ ions were doped into TiO₂ crystal lattice with a part of PtO deposited on the TiO₂ surface. Pt doped TiO₂ exhibited a significantly enhanced activity than pure TiO₂ and P25 for the photocatalytic oxidation of NO_x under irradiation of UV light, simulate sunlight and visible light. An obviously suppressed recombination rate of photo-generated carriers in the Pt doped TiO₂ was demonstrated by photoluminescence (PL) spectroscopy measurements. These results suggested that the synergistic effect of two Pt species coexisted in the catalysts played an important role in the improvement of photocatalytic performance. The photocatalytic reaction mechanisms of NO_x oxidation on the catalyst under UV and visible light irradiation were discussed in detail.
Influence of supports on photocatalytic degradation of phenol and 4-chlorophenol in aqueous suspensions of titanium dioxide
2013, Journal of Environmental Sciences (China)
The photocatalytic degradation of phenol and 4-chlorophenol (4-CP) in aqueous suspensions with the use of titanium dioxide (TiO₂) under UV irradiation was examined. The effects of different supporting materials mixed physically with TiO₂ were studied to achieve maximum degradation efficiency. Among the three supports, namely activated carbon (AC), silica (SiO₂) and zeolite (ZSM-5), all exhibited paramount efficiency for degradation of phenol and 4-CP and was better than TiO₂ alone. The optimum concentration was found to be 50 mg for all supporting materials. The efficiency order of the three supports was as follows: AC > ZSM-5 > SiO₂, respectively. Whilst, the degradation of phenol and 4-CP was improved from 70.6% to 87.6% and 80.6% to 89.7%, respectively, within 120 min photocatalysis in the presence of optimal amount of AC. The degradation was also comparatively enhanced in the presence of cheaper rice husk and the activity was closed to ZSM-5 and lower than AC.
Insights towards the influence of Pt features on the photocatalytic activity improvement of TiO <inf>2</inf> by platinisation
2012, Applied Catalysis B: Environmental
Citation Excerpt :
Even though photodeposition is a widely used method for Pt addition on TiO2, apart from pH or kind of sacrificial agent [3,22,23], the influence of the different experimental parameters during the photo-deposition, such as light intensity and deposition time, has been little studied [24]. Studies on TiO2 platinised by photodeposition often report long irradiation times and high intensity illumination conditions [1,2,5,18,23,25] which probably guarantee total reduction of the metal precursor but cost metal particle growth and agglomeration [26,27]. Thus, the development of preparation methods providing a close control over deposit size, dispersion and chemical state is clearly needed to obtained materials with optimised catalytic properties.
The influence of Pt features, such as particle size, dispersion, oxidation state and amount of metal, on the improvement of the photoactivity of TiO₂ for phenol and methyl orange degradation was studied.
The size of Pt deposits was precisely controlled by changing deposition time under medium light intensity during the photodeposition, with sizes ranging from 3 to 6 nm. Pt oxidation state was also strongly dependent on the photodeposition time.
Photocatalytic activity results showed that the fraction of metallic platinum (Pt⁰) was the crucial factor for the improvement of the activity. When the fraction of Pt⁰ was similar, metal deposit size became the dominant parameter influencing the activity.
The influence of the substrate to be degraded (phenol or methyl orange) was also studied.
Photocatalytic Degradation, Anticancer, and Antibacterial Studies of Lysinibacillus sphaericus Biosynthesized Hybrid Metal/Semiconductor Nanocomposites
2023, Microorganisms

View all citing articles on Scopus

View full text

Effect of platinum on the photocatalytic degradation of chlorinated organic compound

Abstract

Water Research

Applied Catalysis B: Environmental

Water Research

Applied Catalysis B: Environmental

Journal catalyts

Atmospheric Environment

Journal of Physics and Chemistry of Solids

Water Research

Journal of Solid State Chemistry

Journal of Catalysis

Catalysis Today