scholarly journals Reversal of reaction type selectivity by Lewis acid coordination: the ortho photocycloaddition of 1- and 2-naphthaldehyde

2019 ◽  
Vol 10 (37) ◽  
pp. 8566-8570 ◽  
Author(s):  
Simone Stegbauer ◽  
Noah Jeremias ◽  
Christian Jandl ◽  
Thorsten Bach
Keyword(s):  
Visible Light ◽  
Lewis Acid ◽  
Visible Light Irradiation ◽  
Lewis Acids ◽  
Light Irradiation ◽  
Cycloaddition Reactions ◽  
Reaction Type ◽  
Photochemical Behaviour

Lewis acids, such as AlBr3, completely alter the photochemical behaviour of naphthaldehydes. Instead of typical carbonyl photochemistry, the aldehydes undergo cycloaddition reactions at the arene core upon visible-light irradiation.

A diiodo-BODIPY postmodified metal–organic framework for efficient heterogeneous organo-photocatalysis

RSC Advances ◽  
2016 ◽  
Vol 6 (29) ◽  
pp. 23995-23999 ◽  
Author(s):  
Ying Quan ◽  
Qiu-Yan Li ◽  
Quan Zhang ◽  
Wen-Qiang Zhang ◽  
Han Lu ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Metal Organic Framework ◽  
Light Irradiation ◽  
Cycloaddition Reactions ◽  
Highly Active ◽  
Metal Organic ◽  
Organic Framework

A diiodo-BODIPY postmodified MOF acts as a highly active and recyclable heterogeneous photocatalyst for aerobic CDC and oxidation/[3 + 2]cycloaddition reactions under visible light irradiation.

Insights into the Photosensitive Activity of Monolayer HNb3O8 Nanosheets Under Visible Light Irradiation

2020 ◽  
Vol 42 (6) ◽  
pp. 807-807
Author(s):  
Jinhua Xiong Jinhua Xiong ◽  
Jiahang Chen Jiahang Chen ◽  
Xueqing Shao Xueqing Shao ◽  
Xiuzhen Liu Xiuzhen Liu ◽  
Lingyan Fu Lingyan Fu
Keyword(s):  
Visible Light ◽  
Conduction Band ◽  
Lewis Acid ◽  
Visible Light Irradiation ◽  
Strong Interaction ◽  
Acid Sites ◽  
Light Irradiation ◽  
Lewis Acid Sites ◽  
Reaction Solution ◽  
Dissolved O2

Monolayer HNb3O8 nanosheets, as a platform, were prepared for investigating the mechanism of photosensitized degradation of RhB. We found that RhB molecules were capable to absorb on HNb3O8 nanosheets via a strong interaction between the –N(Et)2 group in RhB molecules and surface Lewis acid sites on HNb3O8 nanosheets, contribution to an easier oxidation of RhB molecules. Thanks to the suitable conduction band of HNb3O8 nanosheets, electrons transferred from excited RhB to HNb3O8 nanosheets effectively and reduced the dissolved O2 in the reaction solution into O2-• immediately, resulting in the efficient photosensitized degradation of RhB.

Cu Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity and High Temperature Anatase Stability

2018 ◽  
Author(s):  
Snehamol Mathew ◽  
Priyanka Ganguly ◽  
Stephen Rhatigan ◽  
Vignesh Kumaravel ◽  
Ciara Byrne ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Density Functional ◽  
Anatase Phase ◽  
Sol Gel ◽  
Chemical Properties ◽  
Light Irradiation ◽  
Health Concern ◽  
Bacterial Inactivation ◽  
X Ray

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>.

Semiconductor Photocatalysts for Solar-to-Hydrogen Energy Conversion: Recent Advances of CdS

2020 ◽  
Vol 16 ◽  
Author(s):  
Yuxue Wei ◽  
Honglin Qin ◽  
Jinxin Deng ◽  
Xiaomeng Cheng ◽  
Mengdie Cai ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Visible Light ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Visible Light Irradiation ◽  
Noble Metals ◽  
Light Irradiation ◽  
Photocatalytic Hydrogen Evolution ◽  
Theoretical Design ◽  
Recent Developments

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.

Spatial separation of dual-cocatalysts on bismuth vanadate for selective aerobic oxidation of benzylalcohols to benzaldehydes under visible light irradiation

2018 ◽  
Vol 8 (23) ◽  
pp. 6173-6179 ◽  
Author(s):  
Xu Jin ◽  
Rengui Li ◽  
Yue Zhao ◽  
Xiaodan Liu ◽  
Xiaoqi Wang ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Aerobic Oxidation ◽  
Spatial Separation ◽  
Bismuth Vanadate ◽  
Light Irradiation ◽  
Selective Aerobic Oxidation

Efficient converting of alcohols to aldehydes under visible light can be achieved on BiVO4 crystals with spatial separation of dual-cocatalysts.

Sign in / Sign up

Export Citation Format

Share Document