Photochem

13 pages, 5575 KiB

Open AccessArticle

Preparation of Activated Carbon/TiO₂ Nanohybrids for Photodegradation of Reactive Red-35 Dye Using Sunlight

by Bappy Mondol, Anupam Sarker, A. M. Shareque, Shaikat Chandra Dey, Mohammad Tariqul Islam, Ajoy Kumar Das, Sayed Md. Shamsuddin, Md. Ashraful Islam Molla and Mithun Sarker

Photochem 2021, 1(1), 54-66; https://doi.org/10.3390/photochem1010006 - 18 May 2021

Cited by 42 | Viewed by 4401

Abstract

Activated carbon/titanium dioxide (AC/TiO₂) nanohybrids were synthesized by a hydrothermal technique using various weight percent of commercial AC and were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The synthesized nanohybrids were applied to photodegradation of Reactive Red-35 (RR-35) dye in aqueous solution using sunlight. Due to the synergistic effect of adsorption and photodegradation activity, AC/TiO₂ nanohybrids were more efficient in treating the aqueous dye solution than that of AC and TiO₂. The maximum (95%) RR-35 dye removal from the water was obtained with 20 wt% AC/TiO₂ within 30 min at natural pH of 5.6. The possible photodegradation mechanism of RR-35 dye with AC/TiO₂ was discussed from the scavenger test. Moreover, AC/TiO₂ was found to be suitable for long-term repeated applications through recyclability experiments. Therefore, AC/TiO₂ nanohybrid is a promising photocatalyst for treating azo dyes especially RR-35 from water. Full article

(This article belongs to the Special Issue Visible Light Active Photocatalysts for Environmental Remediation and Organic Synthesis)

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1 pages, 139 KiB

Open AccessEditorial

Photochem—A New Multidisciplinary Open Access Journal for Photochemistry

by Dirk M. Guldi

Photochem 2021, 1(1), 53; https://doi.org/10.3390/photochem1010005 - 28 Apr 2021

Viewed by 2028

Abstract

Welcome to the journal Photochem [...] Full article

15 pages, 11609 KiB

Open AccessArticle

Enhanced Photoluminescence of Electrodeposited Europium Complex on Bare and Terpyridine-Functionalized Porous Si Surfaces

by Min Hee Joo, So Jeong Park, Hye Ji Jang, Sung-Min Hong, Choong Kyun Rhee and Youngku Sohn

Photochem 2021, 1(1), 38-52; https://doi.org/10.3390/photochem1010004 - 6 Apr 2021

Cited by 4 | Viewed by 2617

Abstract

The trivalent Eu(III) ion exhibits unique red luminescence and plays an significant role in the display industry. Herein, the amperometry electrodeposition method was employed to electrodeposit Eu(III) materials on porous Si and terpyridine-functionalized Si surfaces. The electrodeposited materials were fully characterized by scanning electron microscopy, X-ray diffraction crystallography, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Photoluminescence (PL) spectroscopy revealed that PL signals were substantially increased upon deposition on porous Si surfaces. PL signals were mainly due to direct excitation and charge-transfer-indirect excitations before and after thermal annealing, respectively. The as-electrodeposited materials were of a Eu(III) complex consisting of OH, H₂O, NO₃⁻, and CO₃²⁻ groups. The complex was transformed to Eu₂O₃ upon thermal annealing at 700 °C. The electrodeposition on porous surfaces provide invaluable information on the fabrication of thin films for displays, as well as photoelectrodes for catalyst applications. Full article

(This article belongs to the Special Issue Feature Papers in Photochemistry)

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12 pages, 1247 KiB

Open AccessArticle

Photoprotective Properties of Eumelanin: Computational Insights into the Photophysics of a Catechol:Quinone Heterodimer Model System

by Victoria C. Frederick, Thomas A. Ashy, Barbara Marchetti, Michael N. R. Ashfold and Tolga N. V. Karsili

Photochem 2021, 1(1), 26-37; https://doi.org/10.3390/photochem1010003 - 10 Mar 2021

Viewed by 3129

Abstract

Melanins are skin-centered molecular structures that block harmful UV radiation from the sun and help protect chromosomal DNA from UV damage. Understanding the photodynamics of the chromophores that make up eumelanin is therefore paramount. This manuscript presents a multi-reference computational study of the mechanisms responsible for the experimentally observed photostability of a melanin-relevant model heterodimer comprising a catechol (C)–benzoquinone (Q) pair. The present results validate a recently proposed photoinduced intermolecular transfer of an H atom from an OH moiety of C to a carbonyl-oxygen atom of the Q. Photoexcitation of the ground state C:Q heterodimer (which has a π-stacked “sandwich” structure) results in population of a locally excited ππ* state (on Q), which develops increasing charge-transfer (biradical) character as it evolves to a “hinged” minimum energy geometry and drives proton transfer (i.e., net H atom transfer) from C to Q. The study provides further insights into excited state decay mechanisms that could contribute to the photostability afforded by the bulk polymeric structure of eumelanin. Full article

(This article belongs to the Special Issue Feature Papers in Photochemistry)

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16 pages, 1841 KiB

Open AccessFeature PaperArticle

Infrared Spectrum and UV-Induced Photochemistry of Matrix-Isolated Phenyl 1-Hydroxy-2-Naphthoate

by İsa Sıdır, Sándor Góbi, Yadigar Gülseven Sıdır and Rui Fausto

Photochem 2021, 1(1), 10-25; https://doi.org/10.3390/photochem1010002 - 26 Feb 2021

Viewed by 2716

Abstract

The conformational stability, infrared spectrum, and photochemistry of phenyl 1-hydroxy-2-naphthoate (PHN) were studied by matrix isolation infrared spectroscopy and theoretical computations performed at the DFT(B3LYP)/6-311++G(d,p) level of theory. The main intramolecular interactions determining the relative stability of seven conformers of the molecule were evaluated. According to the calculations, the twofold degenerated O–H···O=C intramolecularly hydrogen-bonded conformer with the phenyl ring ester group ±68.8° out of the plane of the substituted naphtyl moiety is the most stable conformer of the molecule. This conformer is considerably more stable than the second most stable form (by ~15 kJ mol⁻¹), in which a weaker O–H···O–C intramolecular hydrogen bond exists. The compound was isolated in cryogenic argon and N₂ matrices, and the conformational composition in the matrices was investigated by infrared spectroscopy. In agreement with the predicted relative energies of the conformers, the analysis of the spectra indicated that only the most stable conformer of PHN was present in the as-deposited matrices. The matrices were then irradiated at various wavelengths by narrowband tunable UV light within the 331.7–235.0 nm wavelength range. This resulted in the photodecarbonylation of PHN, yielding 2-phenoxynaphthalen-1-ol, together with CO. The extension of the decarbonylation was found to depend on the excitation wavelength. Full article

(This article belongs to the Special Issue Feature Papers in Photochemistry)

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9 pages, 4734 KiB

Open AccessArticle

V-Substituted ZnIn₂S₄: A (Visible+NIR) Light-Active Photocatalyst

by Raquel Lucena and José C. Conesa

Photochem 2021, 1(1), 1-9; https://doi.org/10.3390/photochem1010001 - 7 Jan 2021

Cited by 2 | Viewed by 1904

Abstract

ZnIn₂S₄ is known to be a visible light-active photocatalyst. In this work, it is shown that by substituting part of the In atoms with vanadium, the visible light range of photocatalytic activity of such material can be extended, using the so-called in-gap band scheme that has been shown to enhance photovoltaic characteristics. Characterization of this material using several techniques, complemented by DFT calculations, will support this statement. While here only the degradation of aqueous HCOOH in well-aerated conditions is discussed, the same material may be used, with an adequate sacrificial reagent, for photocatalytic H₂ generation. Full article

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Photochem, Volume 1, Issue 1 (June 2021) – 6 articles

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