Vis-Responsive Copper-Modified Titania for Decomposition of Organic Compounds and Microorganisms

Seven commercial titania (titanium(IV) oxide; TiO2) powders with different structural properties and crystalline compositions (anatase/rutile) were modified with copper by two variants of a photodeposition method, i.e., methanol dehydrogenation and water oxidation. The samples were characterized by diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Although zero-valent copper was deposited on the surface of titania, oxidized forms of copper, post-formed in ambient conditions, were also detected in dried samples. All samples could absorb visible light (vis), due to localized surface plasmon resonance (LSPR) of zero-valent copper and by other copper species, including Cu2O, CuO and CuxO (x:1-2). The photocatalytic activities of samples were investigated under both ultraviolet (UV) and visible light irradiation (>450 nm) for oxidative decomposition of acetic acid. It was found that titania modification with copper significantly enhanced the photocatalytic activity, especially for anatase samples. The prolonged irradiation (from 1 to 5 h) during samples’ preparation resulted in aggregation of copper deposits, thus being detrimental for vis activity. It is proposed that oxidized forms of copper are more active under vis irradiation than plasmonic one. Antimicrobial properties against bacteria (Escherichia coli) and fungi (Aspergillus niger) under vis irradiation and in the dark confirmed that Cu/TiO2 exhibits a high antibacterial effect, mainly due to the intrinsic activity of copper species.

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Noble metal-modified titania with visible-light activity for the decomposition of microorganisms

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.9.77 ◽

2018 ◽

Vol 9 ◽

pp. 829-841 ◽

Cited By ~ 11

Author(s):

Maya Endo ◽

Zhishun Wei ◽

Kunlei Wang ◽

Baris Karabiyik ◽

Kenta Yoshiiri ◽

...

Keyword(s):

Antibacterial Activity ◽

Visible Light ◽

Noble Metal ◽

Visible Light Irradiation ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Light Irradiation ◽

Localized Surface Plasmon ◽

Mycelium Growth ◽

X Ray

Commercial titania photocatalysts were modified with silver and gold by photodeposition, and characterized by diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM). It was found that silver co-existed in zero valent (core) and oxidized (shell) forms, whereas gold was mainly zero valent. The obtained noble metal-modified samples were examined with regard to antibacterial (Escherichia coli(E. coli)) and antifungal (Aspergillus niger(A. niger),Aspergillus melleus(A. melleus),Penicillium chrysogenum(P. chrysogenum),Candida albicans(C. albicans)) activity under visible-light irradiation and in the dark using disk diffusion, suspension, colony growth (“poisoned food”) and sporulation methods. It was found that silver-modified titania, besides remarkably high antibacterial activity (inhibition of bacterial proliferation), could also decompose bacterial cells under visible-light irradiation, possibly due to an enhanced generation of reactive oxygen species and the intrinsic properties of silver. Gold-modified samples were almost inactive against bacteria in the dark, whereas significant bactericidal effect under visible-light irradiation suggested that the mechanism of bacteria inactivation was initiated by plasmonic excitation of titania by localized surface plasmon resonance of gold. The antifungal activity tests showed efficient suppression of mycelium growth by bare titania, and suppression of mycotoxin generation and sporulation by gold-modified titania. Although, the growth of fungi was hardly inhibited through disc diffusion (inhibition zones around discs), it indicates that gold does not penetrate into the media, and thus, a good stability of plasmonic photocatalysts has been confirmed. In summary, it was found that silver-modified titania showed superior antibacterial activity, whereas gold-modified samples were very active against fungi, suggesting that bimetallic photocatalysts containing both gold and silver should exhibit excellent antimicrobial properties.

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Preparation of C, N and P co-doped TiO2 and its photocatalytic activity under visible light

Functional Materials Letters ◽

10.1142/s1793604719500450 ◽

2019 ◽

Vol 12 (04) ◽

pp. 1950045 ◽

Cited By ~ 3

Author(s):

Lin Zhao ◽

Yanzhao Xie ◽

Qiuyu Lin ◽

Rongze Zheng ◽

Yong Diao

Keyword(s):

Visible Light ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Soluble Starch ◽

Doping Amount ◽

X Ray ◽

Composite Catalysts ◽

One Step ◽

Co Doped

A series of composite catalysts of C, N and P co-doped TiO2 were prepared by sol-gel method, using a biomass (soluble starch) dopant. The samples were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), fourier transform infrared (FTIR) spectroscopy. The results show that TiO2 is co-doped with C, N and P by one step. The resulting composite exhibited higher specific surface area, wider visible-light absorption band with respect to the pure TiO2. The sample calcined at 400∘C for 2[Formula: see text]h with a doping amount of 6[Formula: see text]g soluble starch showed the best electrochemical performance. The C, N and P co-doped TiO2 was also used for the degradation of methylene blue (MB) and degradation ratio was up to 98% in 80[Formula: see text]min under visible light irradiation.

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Preparation and Characterization of Defective TiO2. The Effect of the Reaction Environment on Titanium Vacancies Formation

Materials ◽

10.3390/ma13122763 ◽

2020 ◽

Vol 13 (12) ◽

pp. 2763

Author(s):

Zuzanna Bielan ◽

Szymon Dudziak ◽

Agnieszka Sulowska ◽

Daniel Pelczarski ◽

Jacek Ryl ◽

...

Keyword(s):

Photocatalytic Activity ◽

Visible Light ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Hydrothermal Reaction ◽

High Photocatalytic Activity ◽

Paramagnetic Resonance ◽

X Ray ◽

Light Activity ◽

Cheap Alternative

Among various methods of improving visible light activity of titanium(IV) oxide, the formation of defects and vacancies (both oxygen and titanium) in the crystal structure of TiO2 is an easy and relatively cheap alternative to improve the photocatalytic activity. In the presented work, visible light active defective TiO2 was obtained by the hydrothermal reaction in the presence of three different oxidizing agents: HIO3, H2O2, and HNO3. Further study on the effect of used oxidant and calcination temperature on the physicochemical and photocatalytic properties of defective TiO2 was performed. Obtained nanostructures were characterized by X-ray diffractometry (XRD), specific surface area (BET) measurements, UV-Vis diffuse reflectance spectroscopy (DR-UV/Vis), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR) spectroscopy. Degradation of phenol as a model pollutant was measured in the range of UV-Vis and Vis irradiation, demonstrating a significant increase of photocatalytic activity of defective TiO2 samples above 420 nm, comparing to non-defected TiO2. Correlation of EPR, UV-Vis, PL, and photodegradation results revealed that the optimum concentration of HIO3 to achieve high photocatalytic activity was in the range of 20–50 mol%. Above that dosage, titanium vacancies amount is too high, and the obtained materials’ photoactivity was significantly decreased. Studies on the photocatalytic mechanism using defective TiO2 have also shown that •O2− radical is mainly responsible for pollutant degradation.

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Significantly Enhanced Aqueous Cr(VI) Removal Performance of Bi/ZnO Nanocomposites via Synergistic Effect of Adsorption and SPR-Promoted Visible Light Photoreduction

Catalysts ◽

10.3390/catal8100426 ◽

2018 ◽

Vol 8 (10) ◽

pp. 426 ◽

Cited By ~ 9

Author(s):

Xiaoya Yuan ◽

Zijuan Feng ◽

Jianjun Zhao ◽

Jiawei Niu ◽

Jiasen Liu ◽

...

Keyword(s):

Electron Microscopy ◽

Synergistic Effect ◽

Visible Light ◽

Photoelectron Spectroscopy ◽

Electrochemical Impedance ◽

Diffuse Reflectance Spectroscopy ◽

X Ray ◽

Enhanced Absorption ◽

Bismuth Nanoparticles ◽

Effective Transfer

Bismuth nanoparticles (BiNPs) and Zinc Oxide photocatalysts (BiNPs/ZnO) with different Bi loadings were successfully prepared via a facile chemical method. Their morphology and structure were thoroughly characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-Vis (Ultraviolet-Visible) diffuse reflectance spectroscopy (DRS), photoluminescence spectra (PL), and electrochemical impedance spectroscopy (EIS). The results showed that a modification of hexagonal wurtzite-phase ZnO nanoparticles with Bi is achievable with an intimate interfacial interaction within its composites. The performance of the photocatalytic Cr(VI) removal under visible light irradiation indicated that BiNPs/ZnO exhibited a superior removal performance to bare ZnO, Bi, and the counterpart sample prepared using a physical mixing method. The excellent performance of the BiNPs/ZnO photocatalysts could be ascribed to the synergistic effect between the considerable physical Cr (VI) adsorption and enhanced absorption intensity in the visible light region, due to the surface plasmon resonance (SPR) as well as the effective transfer and separation of the photogenerated charge carriers at the interface.

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Enhanced Photocatalytic Performance and Mechanism of Au@CaTiO3 Composites with Au Nanoparticles Assembled on CaTiO3 Nanocuboids

Micromachines ◽

10.3390/mi10040254 ◽

2019 ◽

Vol 10 (4) ◽

pp. 254 ◽

Cited By ~ 32

Author(s):

Yuxiang Yan ◽

Hua Yang ◽

Zao Yi ◽

Ruishan Li ◽

Xiangxian Wang

Keyword(s):

Photoelectron Spectroscopy ◽

Photocatalytic Performance ◽

Au Nanoparticles ◽

Diffuse Reflectance Spectroscopy ◽

Localized Surface Plasmon ◽

Hydrothermal Route ◽

Electron Hole ◽

Photoexcited Electron ◽

Au Nps ◽

X Ray

Using P25 as the titanium source and based on a hydrothermal route, we have synthesized CaTiO3 nanocuboids (NCs) with the width of 0.3–0.5 μm and length of 0.8–1.1 μm, and systematically investigated their growth process. Au nanoparticles (NPs) of 3–7 nm in size were assembled on the surface of CaTiO3 NCs via a photocatalytic reduction method to achieve excellent Au@CaTiO3 composite photocatalysts. Various techniques were used to characterize the as-prepared samples, including X-ray powder diffraction (XRD), scanning/transmission electron microscopy (SEM/TEM), diffuse reflectance spectroscopy (UV-vis DRS), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Rhodamine B (RhB) in aqueous solution was chosen as the model pollutant to assess the photocatalytic performance of the samples separately under simulated-sunlight, ultraviolet (UV) and visible-light irradiation. Under irradiation of all kinds of light sources, the Au@CaTiO3 composites, particularly the 4.3%Au@CaTiO3 composite, exhibit greatly enhanced photocatalytic performance when compared with bare CaTiO3 NCs. The main roles of Au NPs in the enhanced photocatalytic mechanism of the Au@CaTiO3 composites manifest in the following aspects: (1) Au NPs act as excellent electron sinks to capture the photoexcited electrons in CaTiO3, thus leading to an efficient separation of photoexcited electron/hole pairs in CaTiO3; (2) the electromagnetic field caused by localized surface plasmon resonance (LSPR) of Au NPs could facilitate the generation and separation of electron/hole pairs in CaTiO3; and (3) the LSPR-induced electrons in Au NPs could take part in the photocatalytic reactions.

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VISIBLE LIGHT ACTIVE Cu2+/TiO2 NANOCATALYST FOR DEGRADATION OF DICHLORVOS

International Journal of Nanoscience ◽

10.1142/s0219581x12500305 ◽

2012 ◽

Vol 11 (05) ◽

pp. 1250030 ◽

Cited By ~ 3

Author(s):

TESHOME ABDO SEGNE ◽

SIVA RAO TIRUKKOVALLURI ◽

SUBRAHMANYAM CHALLAPALLI

Keyword(s):

Catalytic Activity ◽

Visible Light ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Sol Gel ◽

Light Illumination ◽

X Ray ◽

Photo Catalytic Activity ◽

Visible Light Active ◽

Adsorption Desorption

The advantage of doping of TiO2 with copper has been utilized for enhanced degradation of pesticide under visible light irradiation. The sol–gel method has been undertaken for the synthesis of copper-doped TiO2 by varying the dopant loadings from 0.25 wt.% to 1.0 wt.% of Cu2+ . The doped samples were characterized by UV-Visible Diffuse Reflectance Spectroscopy (DRS), N2 adsorption–desorption (BET), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectrometry (EDS). The photocatalytic activity of the catalyst was tested by degradation of dichlorvos under visible light illumination. The results found that 0.75 wt.% of Cu2+ doped nanocatalysts have better photo catalytic activity than the rest of percentages doped, undoped TiO2 and Degussa P25. The reduction of band gap was estimated and the influence of the process parameters on photo catalytic activity of the catalyst has been explained.

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Visible Light-Driven Mn-MoS2/rGO Composite Photocatalysts for the Photocatalytic Degradation of Rhodamine B

Journal of Chemistry ◽

10.1155/2020/6285484 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Thi Thuy Trang Phan ◽

Thanh Tam Truong ◽

Ha Tran Huu ◽

Le Tuan Nguyen ◽

Van Thang Nguyen ◽

...

Keyword(s):

Electron Microscopy ◽

Visible Light ◽

Rhodamine B ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Electron Paramagnetic Resonance Spectroscopy ◽

Resonance Spectroscopy ◽

Paramagnetic Resonance ◽

X Ray ◽

Composite Photocatalysts

The n%Mn-MoS2/rGO (labeled as n%MMS/rGO, where n% = Mn/(Mn + Mo) in mol) composites were successfully prepared by a facile hydrothermal method from the Mn-MoS2 (MMS) and rGO precursors, in which the MMS was obtained by a facile one-step calcination of (NH4)6Mo7O24·4H2O, (NH2)2CS, and Mn(CH3COO)2·4H2O as precursors in N2 gas at 650°C. The samples were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron paramagnetic resonance spectroscopy (EPR), UV-visible diffuse reflectance spectroscopy (UV-Vis DRS), and X-ray photoelectron spectroscopy (XPS), which indicates the composites containing nanosheets of Mn-MoS2 and rGO components. The photocatalytic activities of the n%MMS/rGO composite photocatalysts were evaluated through the photodegradation of rhodamine B (RhB) under the visible light irradiation. The enhancement in the photocatalytic performance of the achieved composites was attributed to the synergic effect of Mn doping and rGO matrix. The investigation of photocatalytic mechanism was also conducted.

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Synthesis of C-N-S-Tridoped TiO2 from Vietnam Ilmenite Ore and Its Visible Light-Driven-Photocatalytic Activity for Tetracyline Degradation

Journal of Nanomaterials ◽

10.1155/2020/1523164 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14 ◽

Cited By ~ 1

Author(s):

Nguyen Thi Lan ◽

Vo Hoang Anh ◽

Hoang Duc An ◽

Nguyen Phi Hung ◽

Dao Ngoc Nhiem ◽

...

Keyword(s):

Electron Microscopy ◽

Photocatalytic Activity ◽

Visible Light ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Nitrogen Adsorption ◽

Photocatalytic Decomposition ◽

Raman Scattering Spectroscopy ◽

X Ray ◽

Visible Light Driven

In this study, C-N-S-tridoped TiO2 composite was fabricated from TiO2 prepared from ilmenite ore and thiourea by means of hydrothermal method. The obtained material was characterized by X-ray diffraction, Raman scattering spectroscopy, UV-Vis diffuse reflectance spectroscopy, nitrogen adsorption-desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). It was found that C-N-S-tridoped TiO2 material has a large specific surface area, showing good photocatalytic activity on the degradation of antibiotic tetracycline in visible light region. The study on the mechanism of tetracycline photodegradation using the liquid chromatography with mass spectrometry was performed. It was found that tetracycline has been degraded over C-N-S-tridoped TiO2 catalyst into many different intermediates which can eventually be converted into CO2 and H2O. The kinetics of photocatalytic decomposition of tetracycline were investigated. In addition, the obtained material could catalyze well the degradation of other antibiotics (ciprofloxacin and chloramphenicol) and dyes (rhodamine-B, methylene blue, and organe red). The catalyst was stable after five recycles with slight loss of catalytic activity, which indicates great potential for practical application of C-N-S-tridoped TiO2 catalyst in treatment of wastewater containing tetracycline in particular or antibiotics in general.

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Photocatalytic performance of Ag2S/ZnO/ZnS nanocomposites with high visible light response prepared via microwave-assisted hydrothermal two-step method

Water Science & Technology ◽

10.2166/wst.2018.466 ◽

2018 ◽

Vol 78 (8) ◽

pp. 1802-1811 ◽

Cited By ~ 1

Author(s):

Jiwei Huang ◽

Changlong Yang ◽

Qiang Song ◽

Dongxue Liu ◽

Li Li

Keyword(s):

Electron Microscopy ◽

Visible Light ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Light Response ◽

Light Sources ◽

Step Method ◽

X Ray ◽

Microwave Assisted ◽

Visible Light Response

Abstract A series of different ratios of Ag2S/ZnO/ZnS nanocomposites with visible light response were prepared by a microwave-assisted hydrothermal two-step method, whose composition, crystalline structure, morphology and surface physicochemical properties were well-characterized via X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (UV–vis/DRS), photoluminescence spectrum (PL), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and N2 adsorption–desorption measurements. Results showed that as-composites mainly consisted of ZnS crystal phase, whose grain size increased obviously compared with non Ag2S samples. At the same time, due to the introduction of narrow band gap Ag2S, the synthesized composite can effectively increase the visible optical absorption of ZnO/ZnS composites. Among them, 1% Ag2S/ZnO/ZnS showed a mixed structure of nano-line and nano-particle, of which BET value increased significantly, and the morphology was more excellent. Photocatalytic activities of a series of Ag2S/ZnO/ZnS composites under different light sources were studied using methyl orange as a model molecule, and 1% Ag2S/ZnO/ZnS was taken as the best one. Meanwhile, 1% Ag2S/ZnO/ZnS also showed a good degradation effect on other dyes with different structures, and its degradation efficiency did not change significantly after three cycles, showing certain stability. In addition, composites with Ag2S loading of 1% possessed the highest hydrogen production ability of photolysis water, indicating that the introduction of Ag2S had significantly enhanced the catalytic performance.

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Visible Light Driven Photoanodes for Water Oxidation Based on Novel r-GO/β-Cu2V2O7/TiO2 Nanorods Composites

Nanomaterials ◽

10.3390/nano8070544 ◽

2018 ◽

Vol 8 (7) ◽

pp. 544 ◽

Cited By ~ 10

Author(s):

Shuang Shuang ◽

Leonardo Girardi ◽

Gian Rizzi ◽

Andrea Sartorel ◽

Carla Marega ◽

...

Keyword(s):

Electron Microscopy ◽

Visible Light ◽

Photoelectron Spectroscopy ◽

Water Oxidation ◽

Electrochemical Impedance ◽

Photocurrent Density ◽

Tio2 Nanorods ◽

X Ray ◽

Visible Light Driven ◽

Linear Voltammetry

This paper describes the preparation and the photoelectrochemical performances of visible light driven photoanodes based on novel r-GO/β-Cu2V2O7/TiO2 nanorods/composites. β-Cu2V2O7 was deposited on both fluorine doped tin oxide (FTO) and TiO2 nanorods (NRs)/FTO by a fast and convenient Aerosol Assisted Spray Pyrolysis (AASP) procedure. Ethylenediamine (EN), ammonia and citric acid (CA) were tested as ligands for Cu2+ ions in the aerosol precursors solution. The best-performing deposits, in terms of photocurrent density, were obtained when NH3 was used as ligand. When β-Cu2V2O7 was deposited on the TiO2 NRs a good improvement in the durability of the photoanode was obtained, compared with pure β-Cu2V2O7 on FTO. A further remarkable improvement in durability and photocurrent density was obtained upon addition, by electrophoretic deposition, of reduced graphene oxide (r-GO) flakes on the β-Cu2V2O7/TiO2 composite material. The samples were characterized by X-ray Photoelectron Spectroscopy (XPS), Raman, High Resolution Transmission Electron Microscopy (HR-TEM), Scanning Electron Microscopy (SEM), Wide Angle X-ray Diffraction (WAXD) and UV-Vis spectroscopies. The photoelectrochemical (PEC) performances of β-Cu2V2O7 on FTO, β-Cu2V2O7/TiO2 and r-GO/β-Cu2V2O7/TiO2 were tested in visible light by linear voltammetry and Electrochemical Impedance Spectroscopy (EIS) measurements.

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