scholarly journals A NEW TYPE OF PHOTOSENSITIZED REACTION INDUCED BY VISIBLE LIGHT ON THE SOLID SURFACE: THE PHOTOCHEMICAL REACTION OF HETEROCYCLICN-OXIDE BY GREEN LIGHT IRRADIATION

1975 ◽  
Vol 4 (5) ◽  
pp. 401-404 ◽  
Author(s):  
Norisuke Hata
2010 ◽  
Vol 24 (15n16) ◽  
pp. 3242-3247 ◽  
Author(s):  
MASAHIRO KATOH ◽  
AKIHIRO IMAYAMA ◽  
NARISUKE MORI ◽  
TOSHIHIDE HORIKAWA ◽  
TAHEI TOMIDA

Introducing different atoms into TiO 2 crystal lattice is a famous method to improve photocatalytic activity of TiO 2 under visible-light irradiation. In this paper, Nitrogen ( N ) and fluorine ( F ) co -doped TiO 2 powders were prepared by mixing TiCl 3 solutions with ammonium fluoride ( NH 4 F ). In preparation, we used NH 3- H 2 O solution for adjustment of pH values (pH 2, 7, and 9) of mixed solution. X-ray diffraction (XRD) indicated N , F - TiO 2 powders prepared at pH7 and pH9 contained only anatase phase, but the powders prepared at pH2 contained both anatase and rutile phase. The result of XRD also indicated N , F - TiO 2 powders prepared at pH7 had the smallest crystallite size. We measured photocatalytic activity of prepared N , F - TiO 2 powders by the decomposition of methylene blue. N , F - TiO 2 powder prepared at pH7 and pH9 showed same high photocatalytic activity under ultraviolet light irradiation (peak wave length = 352 nm). Furthermore, under green light LED irradiation (wave length = 525 nm), a sample prepared at pH7 decomposed methylene blue more quickly than any other samples. As the result, N , F - TiO 2 prepared at pH7 had the best catalytic activity under both UV-light and visible light in the all of N , F - TiO 2 prepared and reference TiO 2 photocatalyst (ST-01 produced by Ishihara Co. Ltd).


RSC Advances ◽  
2017 ◽  
Vol 7 (72) ◽  
pp. 45369-45376 ◽  
Author(s):  
Ke Xu ◽  
Jian Feng

New type of Z-scheme LaFeO3/g-C3N4 heterostructures were successfully prepared and the enhanced photocatalytic hydrogen evolution and degradation activities are presented.


2020 ◽  
Vol 56 (41) ◽  
pp. 5472-5475
Author(s):  
Yasuhiko Iwasaki ◽  
Sukulya Bunuasunthon ◽  
Voravee P. Hoven

Visible light-assisted protein patterning on a solid surface was performed with zwitterionic phosphorylcholine polymers bearing tyrosine residues.


2016 ◽  
Vol 18 (24) ◽  
pp. 16076-16079 ◽  
Author(s):  
Hiroshi Kominami ◽  
Shin-ya Kitagawa ◽  
Yuki Okubo ◽  
Makoto Fukui ◽  
Keiji Hashimoto ◽  
...  

2,3-Dihydroxynaphthalene-modified titania having palladium metal successfully worked as a hydrogen-transfer photocatalyst under visible light irradiation and hydrogen-free conditions.


Synthesis ◽  
2021 ◽  
Author(s):  
Akihiro Orita ◽  
Hikaru Watanabe ◽  
Kazuki Nakajima ◽  
Kento Ekuni ◽  
Ryota Edagawa ◽  
...  

AbstractThe Sonogashira coupling of 1,3,6,8-tetrabromopyrene with 4-[(–)-β-citronellyloxy]phenylethyne was employed to synthesize 1,3,6,8-tetra[4-(citronellyloxy)phenylethynyl]pyrene. The pyrene derivative catalyzed the reductive desulfonylation of ethenyl sulfones via visible-light irradiation (514 nm green light-emitting diodes) in the presence of i-Pr2NEt. The β-citronellyloxy groups provided the sufficient solubility to the highly π-expanded pyrene catalyst, and their polar oxygen functionalities enabled the easy separation of the catalyst from the products via column chromatography.


2020 ◽  
Vol 18 (40) ◽  
pp. 8074-8078
Author(s):  
Kenta Tanaka ◽  
Yosuke Asada ◽  
Yujiro Hoshino ◽  
Kiyoshi Honda

We have developed thioxanthylium photoredox catalyzed [4 + 2] cycloaddition of pentafulvenes at room temperature under green light irradiation, which affords tetrahydrocyclopenta[b]chromenes with high regioselectivities.


Author(s):  
Snehamol Mathew ◽  
Priyanka Ganguly ◽  
Stephen Rhatigan ◽  
Vignesh Kumaravel ◽  
Ciara Byrne ◽  
...  

Indoor surface contamination by microbes is a major public health concern. A damp environment is one potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO<sub>2</sub>) can effectively curb this growing threat.<b> </b>Metal-doped titania in anatase phase has been proved as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu) doped TiO<sub>2 </sub>(Cu-TiO<sub>2</sub>) was evaluated against <i>Escherichia coli</i> (Gram-negative) and <i>Staphylococcus aureus</i> (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO<sub>2 </sub>was carried out <i>via</i> sol-gel technique. Cu-TiO<sub>2</sub> further calcined at various temperatures (in the range of 500 °C – 700 °C) to evaluate the thermal stability of TiO<sub>2</sub> anatase phase. The physico-chemical properties of the samples were characterised through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV-visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO<sub>2</sub> was maintained well, up to 650 °C, by the Cu dopant. UV-DRS results suggested that the visible light absorption property of Cu-TiO<sub>2 </sub>was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasises the introduction of Cu<sup>+</sup> and Cu<sup>2+</sup> ions by replacing Ti<sup>4+</sup> ions in the TiO<sub>2</sub> lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9%) was attained in 30 mins of visible light irradiation by Cu-TiO<sub>2</sub>.


2020 ◽  
Vol 16 ◽  
Author(s):  
Yuxue Wei ◽  
Honglin Qin ◽  
Jinxin Deng ◽  
Xiaomeng Cheng ◽  
Mengdie Cai ◽  
...  

Introduction: Solar-driven photocatalytic hydrogen production from water splitting is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. In this review, recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. In particular, the factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Background: Photocatalytic hydrogen evolution from water splitting using photocatalyst semiconductors is one of the most promising solutions to satisfy the increasing demands of a rapidly developing society. CdS has emerged as a representative semiconductor photocatalyst due to its suitable band gap and band position. However, the poor stability and rapid charge recombination of CdS restrict its application for hydrogen production. The strategy of using a cocatalyst is typically recognized as an effective approach for improving the activity, stability, and selectivity of photocatalysts. Methods: This review summarizes the recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation. Results: Recent developments in CdS cocatalysts for hydrogen production from water splitting under visible-light irradiation are summarized. The factors affecting the photocatalytic performance and new cocatalyst design, as well as the general classification of cocatalysts, are discussed, which includes a single cocatalyst containing noble-metal cocatalysts, non-noble metals, metal-complex cocatalysts, metal-free cocatalysts, and multi-cocatalysts. Finally, future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are described. Conclusion: The state-of-the-art CdS for producing hydrogen from photocatalytic water splitting under visible light is discussed. The future opportunities and challenges with respect to the optimization and theoretical design of cocatalysts toward the CdS photocatalytic hydrogen evolution are also described.


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