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Daria Kądziołka, Paulina Rokicka, Agata Markowska-Szczupak, Antoni W Morawski
BACKGROUND: In public and residential buildings, fungi are usually found in the dust or growing on building materials medium such. It has been known that a number of their spores may contaminate the indoor environment and deteriorate air quality in accommodation spaces. Previously designed air cleaning systems do not guarantee a complete removal of agents harmful to humans and animals. Therefore, there is a great need to develop a new solution to remove molds from indoor air. In recent years, photocatalysis based on titanium dioxide (TiO<sub>2</sub>) has been proposed as an effective method for air pollutants removal...
November 17, 2017: Medycyna Pracy
Rong Zhou, Yi Yiing Goh, Haiwang Liu, Hairong Tao, Lihua Li, Jie Wu
Although developments on the transition-metal-catalyzed hydrosilylation of alkenes have achieved great progress over the past several decades, metal-free hydrosilylation is still rare and highly desirable. Herein, we report a convenient visible-light-driven metal-free hydrosilylation of both electron-deficient and electron-rich alkenes via selective hydrogen atom transfer for Si-H activation. By the synergistic combination of an organo-photocatalyst 4CzIPN and quinuclidin-3-yl acetate catalyst, the hydrosilylation of electron-deficient alkenes exclusively occurred with Si-H activation...
November 16, 2017: Angewandte Chemie
Ji Won Han, Jieun Jung, Yong-Min Lee, Wonwoo Nam, Shunichi Fukuzumi
Photocatalytic hydroxylation of benzene to phenol by dioxygen (O2) occurs under visible light irradiation of an O2-saturated acetonitrile solution containing [Ru(II)(Me2phen)3](2+) as a photocatalyst, [Co(III)(Cp*)(bpy)(H2O)](2+) as an efficient catalyst for both the water oxidation and benzene hydroxylation reactions, and water as an electron source in the presence of Sc(NO3)3. The present study reports the first example of photocatalytic hydroxylation of benzene with O2 and H2O, both of which are the most green reagents, under visible light irradiation to afford a high turnover number (e...
October 1, 2017: Chemical Science
Hiroyuki Tatsumi, Kentaro Teramura, Zeai Huang, Zheng Wang, Hiroyuki Asakura, Saburo Hosokawa, Tsunehiro Tanaka
Modification of the surface of Ga2O3 with rare-earth elements enhanced the evolution of CO as a reduction product in the photocatalytic conversion of CO2 using H2O as an electron donor under UV irradiation in aqueous NaHCO3 as a pH buffer, with the rare-earth species functioning as a CO2 capture and storage material. Isotope experiments using (13)CO2 as a substrate clearly revealed that CO was generated from the introduced gaseous CO2. In the presence of the NaHCO3 additive, the rare-earth (RE) species on the Ga2O3 surface are transformed into carbonate hydrates (RE2(CO3)3•nH2O) and/or hydroxycarbonates (RE2(OH)2(3-x)(CO3)x) which are decomposed upon photoirradiation...
November 16, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Somnath Das, Palani Natarajan, Burkhard König
The C-H amination of benzene derivatives was achieved using DDQ as photocatalyst and BocNH₂ as the amine source under aerobic conditions and visible light irradiation. Electron-deficient and electron-rich benzenes react as substrates with moderate to good product yields. The amine scope of the reaction comprises Boc-amine, carbamates, pyrazoles, sulfonimide and urea. Preliminary mechanistic investigations indicate a charge transfer complex between the amine and DDQ as essential intermediate of the reaction...
November 16, 2017: Chemistry: a European Journal
Xiaobin Liu, Zhenyu Wang, Peng Chen, Huanfu Zhou, Ling Bing Kong, Chunming Niu, Wenxiu Que
Nitrogen-doping approach has been intensively adopted to improve the various properties of metal oxides-especially for adjusting energy band structure and extending photo-response range of oxide photocatalyst. However, nitrogen doped behavior is still unintelligible and complex due to the diversity of the compositions and crystal structures. In this work, new insights into electronic structure and photoelectrochemical property of nitrogen-doping HNb3O8 behaviors were presented. On the one hand, we utilized an in-situ experimental strategy to ascertain the effect of nitrogen-doping on the energy band and photoelectrochemical (PEC) property of HNb3O8 and nitrogen-doped HNb3O8 (N-HNb3O8)...
November 16, 2017: ACS Applied Materials & Interfaces
Weijia Li, Zhaoyong Lin, Guowei Yang
Semiconductor photocatalysis for hydrogen production is a promising route to address current energy demands. It is still a great challenge to spatially separate photogenerated electrons and holes in bulk photocatalysts because of the long carrier transport pathway from the bulk to the surface. 2D heterostructured photocatalysts with the type II band alignment can not only shorten the carrier transport pathway, but also create an electric field at the interface to suppress the carrier recombination. However, ultrathin and intimate-contact 2D heterostructured photocatalysts have rarely been achieved so far...
November 15, 2017: Nanoscale
Andrew M R Hall, Rachael Broomfield-Tagg, Matthew Camilleri, David R Carbery, Anna Codina, David T E Whittaker, Steven Coombes, John P Lowe, Ulrich Hintermair
We demonstrate how FlowNMR spectroscopy can readily be applied to investigate photochemical reactions that require sustained input of light and air to yield mechanistic insight under realistic conditions. The Eosin Y mediated photo-oxidation of N-allylbenzylamine is shown to produce imines as primary reaction products from which undesired aldehydes form after longer reaction times. Facile variation of reaction conditions during the reaction in flow allows for probe experiments that give information about the mode of action of the photocatalyst...
November 15, 2017: Chemical Communications: Chem Comm
T P Shende, B A Bhanvase, A P Rathod, D V Pinjari, S H Sonawane
The present work deals with the preparation of graphene oxide (GO) using Hummers-Offeman method in the presence of ultrasonic irradiations. Further loading of TiO2 photocatalyst on prepared GO was accomplished which is basically oxidation reduction reaction between graphene oxide and titanium isopropoxide that leads to the formation of graphene-TiO2 nanocomposite. Graphene-Ce-TiO2 and Graphene-Fe-TiO2 nanocomposites were prepared using one step in-situ ultrasound assisted method using GO, titanium isopropoxide, cerium nitrate, ferric nitrate, and 2-propanol...
March 2018: Ultrasonics Sonochemistry
Juan Carlos Colmenares, Vaishakh Nair, Ewelina Kuna, Dariusz Łomot
Formation of thin layers of photocatalyst in photo-microreactor is a challenging work considering the properties of both catalyst and the microchannel material. The deposition of semiconductor materials on fluoropolymer based microcapillary requires the use of economical methods which are also less energy dependent. The current work introduces a new method for depositing nanoparticles of TiO2 on the inner walls of a hexafluoropropylene tetrafluoroethylene microtube under mild conditions using ultrasound technique...
March 2018: Ultrasonics Sonochemistry
Masoud Faraji, Neda Mohaghegh, Amir Abedini
A series of g-C3N4-SnO2/TiO2 nanotubes/Ti plates were fabricated via simple dipping of TiO2 nanotubes/Ti in a solution containing SnCl2 and g-C3N4 nanosheets and finally annealing of the plates. Synthesized plates were characterized by various techniques. The SEM analysis revealed that the g-C3N4-SnO2 nanosheets with high physical stability have been successfully deposited onto the surface of TiO2 nanotubes/Ti plate. Photocatalytic activity was investigated using two probe chemical reactions: oxidative decomposition of acetic acid and oxidation of 2-propanol under irradiation...
November 6, 2017: Journal of Photochemistry and Photobiology. B, Biology
Aleksandar R Todorov, Tom Wirtanen, Juho Helaja
Facile photoreductive protocols have been developed to remove benzyl O-protective groups from oxyarene N-heterocycles at positions capable for 2-/4-O-pyridine - 2-/4-pyridone tautomerism. Blue light irradiation, a [Ru] or [Ir] photocatalyst and ascorbic acid in a water-acetonitrile solution debenzylates a variety of aryl N-heterocycles cleanly and selectively. Ascorbic acid has two functions in the reaction. On the one hand, it protonates the N-heterocycles that reduces their reduction potentials notably and on the hand it acts as a sacrificial reductant...
November 14, 2017: Journal of Organic Chemistry
Tadesse Billo, Fang-Yu Fu, Putikam Raghunath, Indrajit Shown, Wei-Fu Chen, Hsiang-Ting Lien, Tzu-Hsien Shen, Jyh-Fu Lee, Ting-Shan Chan, Kuo-You Huang, Chih-I Wu, M C Lin, Jih-Shang Hwang, Chih-Hao Lee, Li-Chyong Chen, Kuei-Hsien Chen
One of the key challenges in artificial photosynthesis is to design a photocatalyst that can bind and activate the CO2 molecule with the smallest possible activation energy and produce selective hydrocarbon products. In this contribution, a combined experimental and computational study on Ni-nanocluster loaded black TiO2 (Ni/TiO2[Vo] ) with built-in dual active sites for selective photocatalytic CO2 conversion is reported. The findings reveal that the synergistic effects of deliberately induced Ni nanoclusters and oxygen vacancies provide (1) energetically stable CO2 binding sites with the lowest activation energy (0...
November 14, 2017: Small
Yongwu Peng, Meiting Zhao, Bo Chen, Zhicheng Zhang, Ying Huang, Fangna Dai, Zhuangchai Lai, Xiaoya Cui, Chaoliang Tan, Hua Zhang
The exploration of new porous hybrid materials is of great importance because of their unique properties and promising applications in separation of materials, catalysis, etc. Herein, for the first time, by integration of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), a new type of MOF@COF core-shell hybrid material, i.e., NH2 -MIL-68@TPA-COF, with high crystallinity and hierarchical pore structure, is synthesized. As a proof-of-concept application, the obtained NH2 -MIL-68@TPA-COF hybrid material is used as an effective visible-light-driven photocatalyst for the degradation of rhodamine B...
November 14, 2017: Advanced Materials
Eakkaphon Rattanangkool, Mongkol Sukwattanasinitt, Sumrit Wacharasindhu
The direct amination reaction of heterocyclic thiols has been developed in the presence of the nonhazardous photocatalyst Rose Bengal under irradiation of visible light. The reaction provides a straightforward approach to pharmaceutically and synthetically useful to 2-aminobenzoxazole and 4-aminoquinazoline derivatives from the corresponding heterocyclic thiols with amines in good to excellent yields. Our photochemical reaction can be successfully adapted into continuous flow reactor which is applicable for large scale chemical industry...
November 14, 2017: Journal of Organic Chemistry
Liping Zhang, Pramila Ghimire, Jenjira Phuriragpitikhon, Baojiang Jiang, Alexandre A S Gonçalves, Mietek Jaroniec
Bismuth/bismuth oxide heterojunction on porous carbon (Bi(0)/Bi2O3@C) was successfully prepared by a surfactant-assisted sol-gel method. This composite photocatalyst was fabricated by depositing Bi2O3 and metallic bismuth nanoparticles (NPs) on porous carbon sheets. Bi NPs were created by in-situ reduction of Bi2O3 with amorphous carbon. During the synthesis, bismuth and carbon precursors were mixed in different ratios, resulting in distinct amounts of metallic bismuth in the composites. The composites showed large specific surface area and pore volume as well as strong light absorption ability due to the existing carbon...
November 6, 2017: Journal of Colloid and Interface Science
M J López-Muňoz, A Daniele, M Zorzi, C Medana, P Calza
The photocatalytic transformation of acesulfame K - an artificial sweetener that has gained popularity over the last decades for being a calorie-free additive in food, beverages and several pharmaceutical products - was studied using three different photocatalysts, the benchmark TiO2-P25 and two other forms of synthetized titanium oxides named TiO2-SG1 and TiO2-SG2. The two latter materials were synthesized by a sol gel process in which the hydrolysis rate of titanium n-butoxide was controlled by the water formed in situ through an esterification reaction between ethanol and acetic acid...
November 4, 2017: Chemosphere
Axel Jacobi von Wangelin, Michael Neumeier, Raul Perez, Michal Majek, Diego Sampedro, Victor de la Pena O'Shea
Photocatalytic bond activations are generally limited by the photon energy and the efficiency of energy and electron transfer processes. Direct two-photon processes provide sufficient energy but the ultra-short lifetimes of the excited states prohibit chemical reactions. The commercial dye 9,10-dicyanoanthracene enabled photocatalytic aromatic substitutions of non-activated aryl halides. This reaction operates under VIS irradiation via sequential photonic, electronic, and photonic activation of the simple organic dye...
November 13, 2017: Chemistry: a European Journal
Jialiang Liang, Jun Deng, Fuyang Liu, Mian Li, Meiping Tong
Bi2MoO6-AgBr hybrid photocatalyst was synthesized via a mixed solvothermal-precipitation method. The as-synthesized photocatalysts were well characterized by Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopic (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX), high resolution transmission electron microscope (HRTEM), UV-vis diffuse reflectance spectra (DRS), as well as photoluminescence spectra (PL). The visible light driven (VLD) disinfection activity of Bi2MoO6-AgBr was tested using Escherichia coli as the model bacteria...
November 8, 2017: Colloids and Surfaces. B, Biointerfaces
Selim Demirci, Metin Yurddaskal, Tuncay Dikici, Cevat Sarıoğlu
In this work, iodine (I) doped hollow and mesoporous Fe2O3 photocatalyst particles were fabricated for the first time through sol-gel method. Phase structure, surface morphology, particle size, specific surface area and optical band gap of the synthesized Fe2O3 photocatalysts were analyzed by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscopy (XPS), BET surface analysis, particle size analyzer and UV-vis diffuse reflectance spectrum (UV-vis DRS), respectively...
November 7, 2017: Journal of Hazardous Materials
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