Journal of the American Chemical Society
·
2021
·
IF 15.419
Zhuang Hu,Yufei Shu,Haiyan Qin,Xiaofei Hu,Xiaogang Peng
With high-quality CdSe/CdS core/shell nanocrystals as the main model system and under a controlled atmosphere, responses of photoexcited semiconductor nanocrystals to two active species (water and/or oxygen) in an ambient environment are studied systematically. Under photoexcitation, although high-quality semiconductor nanocrystals in either thin solid films or various solutions have a near-unity photoluminescence quantum yield, there is still a small probability (∼10–5 per photon absorbed) to be photoreduced by the water molecules efficiently accumulated in the highly hydrophilic nanocrystal–ligands interface. The resulting negatively charged nanocrystals are the starting point of most photophysical variations, and the hydroxyl radical─key photo-oxidation product of water─plays the main role for initiating various photochemical processes. Depending on the supplementation of water to the interface, accessibility to oxygen, photoirradiation power, type of matrices, type of measurement schemes, and solubility of nanocrystals in the solution, various photophysical/photochemical phenomena─either reported or not reported in the literature─are reproducibly observed. Results confirm that photophysical properties and photochemical reactions can be well-correlated, offering a unified and unique basis for fundamental studies and the design of processing techniques in industry.
研究领域:
材料科学
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光化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Science
·
2020
·Vol. 7
·期 14
·2000439
·
IF 15.84
Jundong Shao,Changshun Ruan,Hanhan Xie,Paul K. Chu,Xue-Feng Yu
The photochemical activity of black phosphorus (BP) in near-infrared (NIR) light controlled in situ biomineralization is investigated. Owing to the excellent NIR absorption, irradiation with NIR light not only promotes degradation of BP into PO 4 3− , but also enhances the chemical activity to accelerate the reaction between PO 4 3− and Ca 2+ and promote in situ biomineralization. Mineralization of hydrogels is demonstrated by the preparation of BP incorporated hydrogel (BP@Hydrogel) which delivers greatly improved biomineralization performance under NIR illumination. The biomineralization process which can be controlled by modulating the light irradiation time and location has a high potential in controlling the mechanical properties and osteoinductive ability in tissue engineering. This study also provides insights into the degradation, photochemical activity, and new biological/biomedical applications of BP.
研究领域:
材料科学
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生物医学工程
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光化学
✓ 已验证
DOI
高影响因子
ACS Omega
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2020
·
IF 2.87
Zhigang Zhu,Lin Yang,Yongxian Yu,Lijing Zhang,Shengyang Tao
The integration of light-converting media and microflow chemistry renders new opportunities for high-efficient utilization of solar energy to drive chemical reactions. Recently, we proposed a design of fluorescent fluid photochemical microreactor (FFPM) with a separate light channel and reaction channel, which displays excellent advantages in energy efficiency, flexibility, and general use. However, the limitations of the scalability of the microchannel reactor are still a big challenge to be overcome. Herein, we illustrate the scalability of such an FFPM via a 2n numbering-up strategy by 3D printing technology. Channel shape, number, and interchannel spacing have been optimized, and the serpentine FFPM shows the best scalability with an excellent conversion rate and massive throughput. Reactors with up to eight channels have been fabricated and displayed conversions comparable to that obtained in a single-channel reactor, which provides a feasible strategy and an optimized structure model for batch production of fine chemicals.
研究领域:
化学工程
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材料科学
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光化学
✓ 已验证
DOI
高影响因子
AICHE JOURNAL
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2019
·Vol. 66
·期 2
·e16841
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IF 3.463
Chong Shen,Minjing Shang,Hong Zhang,Yuanhai Su
In this work, we report a simple and inexpensive UV-LEDs based photomicroreactor assembly constructed by commercially available components. The photoisomerization of norbornadiene to quadricyclane was selected to validate this novel photomicroreactor design. Mass transport limitation was eliminated and indicated by dimensionless numbers Fo and Da II , and photons loss was evaluated considering the absorption and reflection of the microreactor walls. The solvents, photosensitizers, and light sources selections were optimized for achieving better photochemical performance and mechanistic insights. The detailed comparison between the high-pressure mercury arc lamp and the UV-LEDs strip revealed great potential of UV-LEDs as appealing light source for photochemical transformations. Moreover, the reaction mechanism was thoroughly discussed and illustrated by the Jablonski diagram indicating electronic states transitions. According to possible intermediate steps, a kinetic model was proposed with the reaction rate constant being correlated with the photon flux, which is valuable for process optimization and further understanding reaction mechanisms.
研究领域:
化学工程
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光化学
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反应动力学
✓ 已验证
DOI
高影响因子
CHEMICAL RESEARCH IN TOXICOLOGY
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2021
·
IF 3.739
Jiaxing He,Mingyue Liu,Lingfeng Yin,Ziqi Deng,Junhong Pang,Haoxian He,Li Dang,Ming-De Li
Carprofen (CP), one kind of a nonsteroidal anti-inflammatory drug, exhibits phototoxic side effects in physiology, while its phototoxic mechanism is ambiguous. To uncover CP’s photophysical and photochemical reaction processes, femtosecond to nanosecond transient absorption spectroscopies were employed to directly detect excited states and transient intermediates of CP upon UV irradiation in pure acetonitrile (MeCN), MeCN/water 1:1, and acid/alkaline buffer solutions. The transient absorption data together with DFT calculations were integrated to elucidate mechanisms for photochemical reactions of CP in different solutions. The associated photophysical and photochemical reaction pathways are dependent on various solution environments. In a pure MeCN solvent, CP is excited to a singlet state (S1) and rapidly interacts with the solvent to proceed solvent rearrangement (SR). It then undergoes vibrational cooling (VC) and proceeds intersystem crossing (ISC) to produce the lowest triplet state (3CP). 3CP finally decays to the ground state. While in a MeCN/water 1:1 solution, deprotonated S1 of CP experiences SR and VC processes, and then it is promoted to a deprotonated triplet state (3CP–). 3CP– undergoes the parallel reactions: dechlorination to a phenyl radical (2CP–) and decarboxylation to a T1 anion (3CP–(de-CO2)). Finally, both intermediates produce the radical anion species 2CP–(de-CO2). In a pH = 7.4 (MeCN/PBS 1:1) solution, 3CP– can be converted into 2CP–(de-CO2) more quickly. Interestingly, we found that the dechlorination step can be promoted in an alkaline solution. Phenyl and chlorine radicals produced in an aqueous solution may be the root cause of the drug’s harmful side effects on the human body. This may be useful to guide the design of related CP drugs with minimal phototoxicity in the pharmaceutical process.
研究领域:
药理学
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光化学
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理论化学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2018
·
IF 6.735
Junhe Lu,Peizeng Yang,Wei Dong,Yuefei Ji,Qingguo Huang
Benzophenone-4 (BP4) is UV-filter that is widely in sunscreens and cosmetics to prevent skin damage from sunlight exposure. Washing off of BP4 from the human body in swimming pools represents a direct source of BP4 in the environment. In this study, we investigated the transformation of BP4 by free chlorine, chloramine, and UV/chlorine, which can be found in swimming pool water. It was found that BP4 can be rapidly removed by both chlorine and chloramine treatment, but only chlorination led to appreciable formation of chlorinated disinfection by-products (DBPs), such as dichloroacetic acid and trichloroacetic acid . However, chloramination of BP4 resulted in higher levels of chlorinated intermediates, which were relatively recalcitrant to further chlorination. The UV/chlorine process was significantly more efficient than the chlorine treatment alone for BP4 removal and resulted in trace chlorinated intermediates and formation of DBPs. Radical scavenger tests revealed that the removal of BP4 in the UV/chlorine process was mostly ascribed to reactions with the Cl and OH generated from HClO photolysis. The presence of methanol as a radical scavenger resulted in incomplete removal of BP4 in the UV/chlorine process and enhanced the formation of DBPs. The increase in DBP formation was because the residual BP4 can be exited to a triplet state ( 3 BP4 ∗ ) upon UV irradiation. 3 BP4 ∗ subsequently reacted with O 2 to form 1 O 2 , a reactive oxygen species that generated DBPs by reacting with chlorinated intermediates in water. All benzophenone-type UV-filters may have similar photochemical activity and thus influence the transformation of other organics in sunlit surface water environments.
研究领域:
环境科学
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水处理工程
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光化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of the American Chemical Society
·
2023
·
IF 15
Jiakuan Zhang,Jiongzhao Li,Zikang Ye,Jiting Cui,Xiaogang Peng
Using CdSe/ZnSe core–shell quantum dots (QDs) as a model, we systematically investigate the photochemical properties of QDs with the ZnSe shells under an ambient environment, which show almost opposite responses to either oxygen or water in comparison with CdSe/CdS core/shell QDs. While the ZnSe shells provide an efficient potential barrier for photoinduced electron transfer from the core to the surface-adsorbed oxygen, they also act as a stepping stone for hot-electron transfer directly from the ZnSe shells to oxygen. The latter process is so effective and competes favorably with ultrafast relaxation of hot electrons from the ZnSe shells to the core QDs, which can completely quench the photoluminescence (PL) with saturated adsorption of oxygen (1 bar) and initiate oxidation of the surface anion sites. Water can slowly eliminate the excess hole to neutralize the positively charged QDs, partially canceling the photochemical effects of oxygen. Alkylphosphines─through two distinctive reaction pathways with oxygen─stop the photochemical effects of oxygen and completely recover PL. With limited thickness (around two monolayers), the ZnS outer shells substantially slow down photochemical effects on CdSe/ZnSe/ZnS core/shell/shell QDs but cannot fully stop PL quenching by oxygen.
研究领域:
材料科学
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光化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
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2020
·
IF 3.871
Xiao Sheng,Yuanzhi Zheng,Wenjing Li,Ruomei Gao,Le Du,Yujun Wang
Selective dimension enlarging integrated with numbering-up is of great importance for microfluidics. However, its feasibility for photochemical processes remains unclear due to the strict requirements of uniform irradiation. Herein, a novel method for selective dimension enlarging in photochemical production was developed by introducing microbubbles. A membrane dispersion microreactor was employed to generate microbubbles for efficient mixing and uniform absorption of photons. With an increased channel size from 0.6 mm to 4 mm, it allowed a 41-fold increase in productivity while maintaining the microscale effect. The yield of was increased by 44–70 % with 83–86% less side products, compared with those of the homogeneous and segmented flow systems. In addition, a theoretical method combining CFD simulation was developed to predict the change of mixing time with device scales, which could be used to assess the practicality by selective dimension enlarging for different photochemical microfluidic processes.
研究领域:
化学工程
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微流体技术
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光化学
✓ 已验证
产品关联
DOI
高影响因子
PHOTOCHEMISTRY AND PHOTOBIOLOGY
·
2013
·Vol. 90
·期 3
·496-502
·
IF 2.287
Kun Li,Qin Zhang,Mei Wang,Rongrong Zhu,Xiaoyu Sun,Xianzheng Wu,Shi-Long Wang
Tanshinone IIA (Tan IIA) has the properties of cardiovascular protection, anti-inflammation, antioxidation and anticancer. Its light-induced instability has drawn our interests in its photochemistry. Therefore, laser flash photolysis herein was used to investigate the transient photochemistry of Tan IIA. Our results show that direct photoexcitation by 355 nm laser pulses or photosensitization by energy transfer can lead to the formation of the triplet state of Tan IIA ( 3 Tan IIA*). The triplet absorption spectrum and molar absorption coefficient, and ISC quantum yield were determined. Self-quenching of 3 Tan IIA* by its ground state was identified as an autooxidation reaction. 3 Tan IIA* was proved to react quickly with N , N -dimethylaniline, tert-butylhydroquinone and propyl gallate via electron transfer with the diffusion-controlled rate constants. One of the products with maximum absorption around 390 nm was assigned to the radical anion of Tan IIA. Our results indicate that 3 Tan IIA* is a reactive transient species and can be generated by photosensitization or direct photoexcitation. According to our results, the possible role of Tan IIA as a photosensitizer to induce potential phototoxicity via Type-II pathway in the presence of O 2 can be predicted.
研究领域:
药理学
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光化学
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生物医学工程
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2024
·
IF 8.1
Yuliya E. Tyutereva,Olga A. Snytnikova,Dmitriy G. Sheven,Roman G. Fedunov,Vadim V. Yanshole,Vyacheslav P. Grivin,Ivan P. Pozdnyakov
Mechanism of direct UV photolysis of the zwitterionic and anionic forms of the quinolone antibiotic ciprofloxacin (CIP) was revealed by combination of nanosecond laser flash photolysis, steady-state photolysis coupled with high resolution LC-MS and DFT quantum-chemical calculations. For both forms, the main intermediate is a dissociative triplet state, which loses a fluorine ion to form a triplet carbocation; subsequent solvent attack of the latter leads to the formation of products of hydroxylation both the aromatic ring and the piperazyl substituent. Correspondingly, the quantum yield of photolysis of both CIP forms does not depend on the excitation wavelength, but depends on the concentration of dissolved oxygen. Secondary photolysis leads to a number of products of oxidation of the aromatic system, as well as oxidation, opening and full destruction of the piperazinyl substituent. The results obtained may be important for understanding the fate of quinolone antibiotics in UVC disinfection processes and in natural waters under the action of sunlight.
研究领域:
环境科学
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药物化学
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光化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Jiaojiao Fan,Yuanzhi Zheng,Yingtian Yang,Le Du,Yujun Wang
Ultraviolet B (UVB) irradiation is of great importance for photochemical synthesis of steroidal intermediates, which could be efficiently provided by neither traditional mercury lamps nor novel light-emitting diodes. Herein, a photochemical microfluidic strategy with enhanced UVB irradiation was developed by the integration of novel photoluminescent composite films, which were readily prepared to shift the emission peak. The UVB emission intensity was increased by approximately 10 times for an 8 W lamp with this flexible and removable film. It allowed a productivity as high as that of a 100 W lamp without using any cooling devices, showing great potential to replace traditional medium-pressure mercury lamps for UVB-irradiated synthesis. In addition, a calculation method was developed to assess the effect of specific wavelengths based on the photon flux and photonic efficiency, which could provide theoretical guidance for photochemical microfluidic processes to refine the emission ranges.
研究领域:
化学工程
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材料科学
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光化学
✓ 已验证
产品关联
DOI
高影响因子
ACS ES&T Water
·
2022
·
IF 0
Teng Zhang,Yuefei Ji,Jean-Marc Chovelon,Junhe Lu
Benzophenone (BP) UV filters are a group of contaminants of emerging concern. In this study, we found that 2,4-dihydroxybenzophenone (BP1) was more liable to photodegradation than the other BPs. Particularly, an accelerated degradation of BP1 was observed under UV365nm irradiation. Singlet oxygen (1O2) was identified as the key reactive species leading to its degradation. Generation of 1O2 was mostly ascribed to certain photodegradation products of BP1. These products have an aromatic ketone structure and can be excited to the activated triplet state, giving rise to 1O2. Intriguingly, the reaction between BP1 and 1O2 generated more photochemically reactive products. Thus, the removal of BP1 appeared to be accelerated. A total of four such products, that is, 2-methylenenaphthalen-1(2H)-one, (E)-2-(1-oxonaphthalen-2(1H)-ylidene)-acetic acid, (1-oxo-1H-benzo[c]oxepin-3-ylidene)-acetic acid, and 2-oxo-3-(1-oxo-1H-benzo[c]oxepin-3-ylidene)-propionic acid, were identified. In addition to sensitizing the photodegradation of the parent BP1, these products can also lead to the indirect photodegradation of other organic contaminants, such as isoproturon. To the best of our knowledge, such photochemical activity of BP1 has not been reported. It indicates that the presence of BP1 can influence the transformation of other organics in sunlit surface waters or UV-based water treatment processes, which comprises an important aspect of its environmental behavior and merits further study.
研究领域:
环境科学
·
光化学
✓ 已验证
产品关联
DOI
危险品化学品经营许可证（带存储）