scholarly journals Synthesis and Photochemical Properties of Monolithic TiO2 Nanowires Diode

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3636
Author(s):  
Massimo Zimbone ◽  
Maria Cantarella ◽  
Giuliana Impellizzeri ◽  
Sergio Battiato ◽  
Lucia Calcagno
Keyword(s):  
Degradation Rate ◽  
Uv Light ◽  
Pt Nanoparticles ◽  
Rear Side ◽  
Tio2 Nanowires ◽  
Photo Degradation ◽  
Rutile Structure ◽  
Scavenging Effect ◽  
Photochemical Properties ◽  
Structural Characterizations

In this paper, the structural and photochemical properties of a monolithic photochemical diode are discussed. The present structure is composed, from the top to the bottom, of a TiO2 nanowire layer, a TiO2 film, a Ti foil, and a porous layer made of Pt nanoparticles. The synthesis of the nanowires was simply carried out by Au-catalysed-assisted process; the effects of the annealing temperature and time were deeply investigated. Morphological and structural characterizations were performed by scanning electron microscopy and Raman spectroscopy. The analyses showed the rutile structure of the TiO2 nanowires. The photocatalytic properties were studied through the degradation of methylene blue (MB) dye under UV light irradiation. The nanowires induced an enhancement of the photo-degradation rate, compared to TiO2 in a bulk form, due to an increase in the surface area. Moreover, the presence of a nano-porous Pt layer deposited on the rear side of the samples provided a further increase in the MB degradation rate, related to the scavenging effect of Pt nanoparticles. The overall increment of the photo-activity, due to the nano-structuration of the TiO2 and to the presence of the Pt layer, resulted a factor 7, compared to the bulk reference. In addition, photovoltage measurements allowed to assess the effects of TiO2 nano-structuration and Pt nanoparticles on the electron accumulation.

Electronic Spectral Investigations upon the Photochemical Transformations of Some Substituted 1-(N,N-bisacyl)amino-4,5-diphenyl-l,2,3-triazoles

2001 ◽  
Vol 56 (6-7) ◽  
pp. 452-458
Author(s):  
Irina Petkova ◽  
Apostolos J. Maroulis ◽  
Constantina Hadjiantoniou-Maroulis ◽  
Peter Nikolov
Keyword(s):  
Steady State ◽  
Room Temperature ◽  
Uv Light ◽  
Uv Absorption ◽  
Luminescence Spectra ◽  
Model Compounds ◽  
Photochemical Transformations ◽  
Absorption And Luminescence Spectra ◽  
Photochemical Properties ◽  
Substituted 1

Abstract The objective of this report is to investigate the steady state and dynamic photophysical and photochemical properties of 1-(N,N-bisacyl)amino-4,5-diphenyl-1,2,3-triazoles in solvents of dif­ferent polarity at room temperature and in frozen matrix at 77 K. On the basis of the comparison of their UV absorption and luminescence spectra with those of 4,5-diphenyl-1,2,3-triazole and diben-zamide (model compounds), cleavage of the N-N bond in the title compounds after irradiation with polychrome UV light is proved.

scholarly journals Degradasi Tirosina Menggunakan Mangkinfoto Berasaskan TiO2

2012 ◽  
Author(s):  
Rusmidah Ali ◽  
Siti Salamah Maisoan @ Selamat
Keyword(s):  
Amino Acid ◽  
Metal Ions ◽  
Uv Light ◽  
Degradation Process ◽  
Aqueous System ◽  
Visible Spectroscopy ◽  
Photo Degradation ◽  
Efficient System ◽  
Catalyst Powder ◽  
Uv Visible

Asid amino merupakan bahan asas dalam tisu tumbuhan dan haiwan. Tirosina (Tr) salah satu jenis asid amino yang mengandungi gelang aromatik, telah dipilih sebagai sampel untuk proses degradasi dalam medium akueus. Ini bertujuan melihat kesan penggunaan mangkinfoto dalam sinaran ultralembayung (λ < 400 nm) atau cahaya matahari ke atas molekul tirosina. Kajian telah dijalankan menggunakan sistem cahaya, mangkin serbuk TiO2, hidrogen peroksida, H2O2 dan ion logam. Penambahan ion logam seperti Ni2+, Cu2+, Ag+, Mn2+, Co2+, Fe2+ dan Cd2+ dan agen pengoksidaan, iaitu hidrogen peroksida adalah untuk mendapatkan kaedah yang paling cekap. Keputusan menunjukkan penambahan H2O2 dan ion Fe2+ dan Ni2+ berjaya meningkatkan kecekapan proses degradasifoto tirosina. Ion Ni2+ memberikan keputusan terbaik berbanding ion-ion lain. Ion Cu2+, Ag+, Mn2+ dan Cd2+ merencat proses degradasi. Keputusan juga menunjukkan cahaya matahari adalah setanding dengan cahaya ultralembayung. Kepekatan H2O2 terbaik adalah 5.0 x 10-2M dan semakin banyak TiO2 digunakan semakin baik peratus degradasi tirosina. Oleh itu kaedah optimum untuk proses degradasifoto ialah Tr 2.5 x 10-4 M + TiO2 + H2O25.0 x 10-3 M + Mn+ 1.0 x 10-2 M. Proses degradasifoto dikaji menggunakan spektroskopi ultralembayung-nampak pada julat panjang gelombang 400-200 nm. Kata kunci: Tirosina; degradasifoto; serbuk TiO; akueus Amino acid is a basic component in plant or animal tissue. Tyrosine (Tr), an amino acid which contains aromatic ring, was chosen as a sample for a photodegradation process in an aqueous system. The purpose of the experiment is to study the effect of photocatalysis under UV (λ < 400 nm) or sunlight on tyrosine. The experiment was carried out by using UV light, catalyst powder (TiO2), hidrogen peroxide H2O2 and metal ions system. The addition of oxidising agent H2O2 and metal ions such as Ni2+, Cu2+, Ag+, Mn2+, Co2+, Fe2+ and Cd2+ were used in order to achieve the most efficient system. Results showed that the system with added H2O2 and metal ions such as Ni2+ and Fe2+ had successfully enhanced the process of the tyrosine photodegradation. Other metal ions system such as Cu2+, Ag+, Mn2+ and Cd2+ were found to inhibit the degradation process. The results also showed that sunlight was comparable to ultraviolet light. The best H2O2 concentration was 5.0 x 10-2 M and the percentage of tyrosine degradation increased with the addition of more TiO2) by mass. Therefore, the optimum condition for tyrosine photodegradation process was in Tr 2.5 x 10-4 M + TiO2 + H2O2 5.0 x 10-3 M + H2O2 1.0 x 10-2 M. The dissappearance of tyrosine in the photo degradation process was monitored by UV-visible spectroscopy between 400-200 nm. Key words: Tyrosine; photodegradation; TiO2 powder; akueus

scholarly journals Removal of 17β-Estradiol by Activated Charcoal Supported Titanate Nanotubes (TNTs@AC) through Initial Adsorption and Subsequent Photo-Degradation: Intermediates, DFT calculation, and Mechanisms

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2121
Author(s):  
Taobo Huang ◽  
Baozhu Pan ◽  
Haodong Ji ◽  
Wen Liu
Keyword(s):  
Activated Charcoal ◽  
Density Functional ◽  
Capillary Condensation ◽  
Uv Light ◽  
Density Functional Theory Calculation ◽  
Titanate Nanotubes ◽  
Photo Degradation ◽  
Photocatalytic Ability ◽  
17Β Estradiol ◽  
Initial Adsorption

A low-cost composite of activated charcoal supported titanate nanotubes (TNTs@AC) was developed via the facile hydrothermal method to remove the 17β-estradiol (E2, a model of pharmaceutical and personal care products) in water matrix by initial adsorption and subsequent photo-degradation. Characterizations indicated that the modification occurred, i.e., the titanate nanotubes would be grafted onto the activated charcoal (AC) surface, and the micro-carbon could modify the tubular structure of TNTs. E2 was rapidly adsorbed onto TNTs@AC, and the uptake reached 1.87 mg/g from the dual-mode model fitting. Subsequently, the adsorbed E2 could be degraded 99.8% within 2 h under ultraviolet (UV) light irradiation. TNTs@AC was attributed with a unique hybrid structure, providing the hydrophobic effect, π−π interaction, and capillary condensation for E2 adsorption, and facilitating the electron transfer and then enhancing photocatalytic ability for E2-degradation. In addition, the removal mechanism of E2 was elucidated through the density functional theory calculation. Our study is expected to provide a promising material for environmental application.

scholarly journals Preparation, Characterization, and Performance Analysis of S-Doped Bi2MoO6 Nanosheets

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1341 ◽  
Author(s):  
Ruiqi Wang ◽  
Duanyang Li ◽  
Hailong Wang ◽  
Chenglun Liu ◽  
Longjun Xu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Degradation Rate ◽  
X Ray Diffraction ◽  
Photo Degradation ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir ◽  
And Performance ◽  
Adsorption Desorption ◽  
Excellent Stability

S-doped Bi2MoO6 nanosheets were successfully synthesized by a simple hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption–desorption isotherms, Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), elemental mapping spectroscopy, photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS), and UV-visible diffused reflectance spectra (UV-vis DRS). The photo-electrochemical performance of the samples was investigated via an electrochemical workstation. The S-doped Bi2MoO6 nanosheets exhibited enhanced photocatalytic activity under visible light irradiation. The photo-degradation rate of Rhodamine B (RhB) by S-doped Bi2MoO6 (1 wt%) reached 97% after 60 min, which was higher than that of the pure Bi2MoO6 and other S-doped products. The degradation rate of the recovered S-doped Bi2MoO6 (1 wt%) was still nearly 90% in the third cycle, indicating an excellent stability of the catalyst. The radical-capture experiments confirmed that superoxide radicals (·O2−) and holes (h+) were the main active substances in the photocatalytic degradation of RhB by S-doped Bi2MoO6.

Profiling of the Mechanical Properties of Ultralow-k Films Using Nanoindentation Techniques

2011 ◽  
Vol 1297 ◽  
Author(s):  
Holm Geisler ◽  
Ulrich Mayer ◽  
Matthias U. Lehr ◽  
Petra Hofmann ◽  
Hans-Juergen Engelmann
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Light Absorption ◽  
Uv Light ◽  
Lower Surface ◽  
Rear Side ◽  
Plastic Properties ◽  
Dynamic Mechanical ◽  
Reduced Modulus ◽  
Good Agreement

ABSTRACTSeveral nanoindentation techniques were applied to the surface, the reverse side and cross-sections of PECVD ultralow-k (ULK) film stacks to characterize their elasto-plastic properties quantitatively. Results showed good agreement of the reduced modulus (Er) values measured from above and on cross-sections, respectively. Er decreased by 10-22% from the upper to the lower surface of the films. This gradient suggests that UV light absorption inside the film leads to slightly reduced curing at the rear side of the films compared to the surface of the ULK layers. Both quasi-static nanoindentation and dynamic mechanical mapping showed this trend. It is demonstrated that quantitative mechanical mapping can be performed with a lateral resolution ≤ 100nm. Slight local variations of Er were detected on ULK/SiCxNy films stacked on top of Cu-low-k interconnect structures.

UV Light Stability of α-Cyclodextrin/Resveratrol Host - Guest Complexes and Isomer Stability at Varying pH

2009 ◽  
Vol 62 (8) ◽  
pp. 921 ◽  
Author(s):  
Kerrilee E. Allan ◽  
Claire E. Lenehan ◽  
Amanda V. Ellis
Keyword(s):  
Inclusion Complex ◽  
Uv Light ◽  
Sodium Dodecyl ◽  
Molar Absorptivity ◽  
Photo Degradation ◽  
Light Stability ◽  
Uv Visible ◽  
The Stability ◽  
Ph Range ◽  
Cis Isomer

trans-Resveratrol is an antioxidant that readily isomerizes to the cis isomer under UV irradiation. Here we report on the UV-Visible analysis of the stability of both trans- and cis-resveratrol isomers in the presence of UV light over a pH range of 2.0–9.0 in a phosphate-borate buffer that contains sodium dodecyl sulphate and acetonitrile. The molar absorptivity of the trans-resveratrol solution absorbing at 320 nm (3.88 eV) and 305 nm (4.07 eV) was 33000 and 34000 M–1 cm–1, respectively. Results indicate that trans-resveratrol has a slower isomerization within a pH range of 5.0–8.0. A pH > 8.0 results in almost immediate isomerization of the sample, whereas at pH 2.0 a photo-degradation product appears at 260 nm (4.77 eV). This was not apparent at pH 8.0. By including trans-resveratrol into a trans-resveratrol/α-cyclodextrin host–guest inclusion complex in pH 8.0 buffer isomerization was greatly reduced, with enhanced trans-resveratrol photostability.

The Preparation of C, N, S Tri-Doped TiO2 and Visible-Light Photo-Degradation of Methylene Blue and Dyes

2011 ◽  
Vol 287-290 ◽  
pp. 1735-1743 ◽  
Author(s):  
Yi Dong Shi ◽  
Qiong Guo ◽  
Yuan Song Xie
Keyword(s):  
Methylene Blue ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Degradation Rate ◽  
Raw Material ◽  
Precipitation Method ◽  
Light Sources ◽  
Visible Absorption ◽  
Photo Degradation ◽  
X Ray

The C, N, S tri-doped TiO2 with high visible-light photo-catalysis effect was successfully prepared by mixing thiourea with the self-prepared TiO2 powder through calcining for 2h at 450°C. The TiO2 powder was obtained by homogeneous precipitation method using the metatitanic acid instead of expensive chemical reagents contained Ti as raw material. The effect of doping materials and methods on the photo-degradation rate of methylene blue and dyes was studied. The characterizations of the doped TiO2 were analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible absorption spectra (UV-vis). The results showed that this sample was the anatase TiO2 and contained elements C, N, S. The sample exhibited a significant response to ultraviolet and visible light. In the photo-degradation experiment, the C, N, S, tridoped-TiO2 could decolorize methylene blue and textile dyes quickly, and the photo-degradation rate of methylene blue could reach upward 98% after 3 hours under the different light sources.

Effect of ammonium salts on the photochemical degradation of iron containing organic aerosol

2020 ◽  
Author(s):  
Ulrich Krieger ◽  
Nir Bluvshtein ◽  
Jing Dou
Keyword(s):  
Citric Acid ◽  
Gas Phase ◽  
Degradation Rate ◽  
Uv Light ◽  
Lower Troposphere ◽  
Organic Aerosol ◽  
Photochemical Degradation ◽  
Single Particles ◽  
Electrodynamic Balance ◽  
Humidity Dependence

&lt;p&gt;Formation of organic aerosol by oxidation of gas phase compounds has been intensely studied, and is much better understood than the aerosol ageing transformations during the lifetime of organic aerosol. Aerosol ageing influences how those aerosol particles affect climate and human health and is still not well constrained in current models.&lt;/p&gt;&lt;p&gt;Photochemistry in the condensed phase is an important mechanism responsible for ageing of organic aerosol. In the lower troposphere, where UV light intensity with sufficiently low wavelength to directly photolyze aerosol components is low, indirect photochemistry (catalyzing redox processes of non-absorbing molecules) is especially relevant. Recently we studied transition metal complex photochemistry in single particles levitated in an electrodynamic balance. In particular, we investigated the aqueous iron(III)-citrate/citric acid system and found that irradiation at 473 nm led to rapid and significant degradation of the citric acid. Up to 80% of the initial particle mass was partitioned to the gas phase with the degradation rate depending on kinetic transport limitations of oxygen. These kinetic limitations arise are influenced strongly by the relative humidity dependence of particle viscosity where water acts as a plasticizer.&lt;/p&gt;&lt;p&gt;Here we will report on photochemical degradation experiments adding various salts in different (ammonium sulfate, ammonium bisulfate, etc.) to the reference system iron(III)-citrate/citric acid. Preliminary experiments suggest that pH of the aerosol particle influences the degradation rate in this system significantly.&lt;/p&gt;

Photo Catalytic Properties of Fe-Modified and Magnetic Nanotitanium Prepared by Hydrothermal Method

2013 ◽  
Vol 743-744 ◽  
pp. 843-848
Author(s):  
Ya Ping Zhang ◽  
Qian Qian Zhi ◽  
Lian Qing Yu ◽  
Kai Tuo Dong ◽  
Ri Shan Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrothermal Method ◽  
Degradation Rate ◽  
Crystal Morphology ◽  
Separation Efficiency ◽  
Uv Light ◽  
Mercury Lamp ◽  
Photo Catalytic Activity ◽  
Reaction Solution ◽  
Fe Addition

In order to improve the separation efficiency and the circular utilization ratio of the catalyst, the Fe-doped nanotitanium and nanotitanium supported on Fe2O3 carrier was prepared by hydrothermal method. The tetra-butyl titanate and ethanol were used as starting materials to prepare nanotitanium. The results of Fe-doped nanotitanium showed that the doping of iron changed the nanotitanium crystal and crystal morphology. No matter UV-light or mercury lamp 577 nm irradiation, the samples with 0.5 mM Fe addition showed the highest photo catalytic activity, with degradation rate of methyl blue above 95%. The structure, photo catalytic activity and magnetic properties analysis showed that the magnetic nanotitanium met the purpose of separation between the catalyst and reaction solution. The photo catalytic activity of nanotitanium supported on Fe2O3 carrier has respond to visible light. With mercury lamp 577 nm as irradiation source, degradation rate of methylene blue light could reach 63.40%.

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