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Главная страница Новости науки Journal of Photochemistry and Photobiology C: Photochemistry Reviews
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ScienceDirect Publication: Journal of Photochemistry and Photobiology C: Photochemistry Reviews
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ScienceDirect Publication: Journal of Photochemistry and Photobiology C: Photochemistry Reviews
  • Applied photoelectrocatalysis on the degradation of organic pollutants in wastewaters
    Publication date: June 2017
    Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 31

    Author(s): Sergi Garcia-Segura, Enric Brillas

    A large variety of electrochemical advanced oxidation processes (EAOPs) have been recently developed to remove organic pollutants from wastewaters to avoid their serious health-risk factors from their environmental accumulation and to reuse the treated water for human activities. The effectiveness of EAOPs is based on the in situ production of strong reactive oxygen species (ROS) like hydroxyl radical (OH). Photoelectrocatalysis (PEC) has emerged as a promising powerful EAOP by combining photocatalytic and electrolytic processes. It consists in the promotion of electrons from the valence band to the conduction band of a semiconductor photocatalyst upon light irradiation, with production of positive holes. The fast recombination of the electron/hole pairs formed is avoided in PEC by applying an external bias potential to the photocatalyst that extracts the photogenerated electrons up to the cathode of the electrolytic cell. Organics can be oxidized directly by the holes, OH formed from water oxidation with holes and other ROS produced between the electrons and dissolved O2. This paper presents a general and critical review on the application of PEC to the remediation of wastewaters with organic pollutants. Special attention is made over the different kinds of photocatalysts utilized and preparation methods of the most ubiquitous TiO2 materials. Typical PEC systems and main operation variables that affect the effectiveness of the degradation process are also examined. An exhaustive analysis of the advances obtained on the treatment of dyes, chemicals and pharmaceuticals from synthetic solutions, as well as of real wastewaters, is performed. Finally, research prospects are proposed for the future development of PEC with perspectives to industrial application.







  • Non-equilibrium effects in ultrafast photoinduced charge transfer kinetics
    Publication date: December 2016
    Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 29

    Author(s): Serguei V. Feskov, Valentina A. Mikhailova, Anatoly I. Ivanov

    Modern laser-based spectroscopy has provided methods for detection ultrafast photochemical transformations occurring on the timescale of intramolecular and solvent reorganization. Such processes usually proceed in non-equilibrium regime, in parallel with nuclear relaxation, and often manifest strong deviations from the Kasha–Vavilov rule. In particular, they offer a possibility to control the yield of photoinduced electron transfer (ET) by using different excitation wavelengths. In the last decade the non-equilibrium charge transfer (CT) processes have attracted considerable interest from the scientific community due to their determining role in photosynthesis, dye-sensitized solar cells and various molecular electronic devices. Non-equilibrium of nuclear (intramolecular and solvent) degrees of freedom can be created by a pump pulse or by photoreaction itself at some of its stages. In this review both situations are considered and illustrated by examples in which non-equilibrium effects are pronounced. It is shown that ultrafast charge recombination in photoexcited donor–acceptor complexes and photochemical processes in donor–acceptor1–acceptor2 molecular compounds proceed predominantly in non-equilibrium (hot) regime. It is important that kinetics and product yields of these reactions demonstrate regularities that considerably differ from that observed in thermal reactions. Among them, the lack of the Marcus normal region in the free energy gap law for charge recombination of the excited donor–acceptor complexes, extremely low quantum yields of the thermalized charge separated states in ultrafast CT from the second excited state of the donor are most known. Although there have been many efforts to clarify microscopic mechanisms of non-equilibrium photoreactions by using ultrafast time-resolved spectroscopy techniques, control of the rate and efficiency of photoinduced charge transfer reactions is still an open challenge. One of the most important applications here is a suppression of ultrafast charge recombination in CT systems, formed either by direct optical excitation or by the preceding ET step. In these systems charge recombination is often regarded as undesirable process, leading to the loss of energy and selectivity of photoreaction. In this review some strategies of ultrafast charge recombination suppression are discussed. The non-equilibrium effects are interpreted from a unified point of view in context of the multichannel point-transition stochastic model. This approach demonstrates similarities and differences in ET mechanisms in various donor–acceptor molecular systems and allows formulating general regularities inherent to these phenomena. We believe that new advances in this research area will not only help to discover new fundamental information about these regularities, but will also have impact on many emerging technologies where ultrafast CT plays the central role.

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  • Reaction dynamics of excited radical ions revealed by femtosecond laser flash photolysis
    Publication date: June 2018
    Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 35

    Author(s): Mamoru Fujitsuka, Tetsuro Majima

    Herein, we review studies on the dynamics of excited radical ions. The enhanced reactivities of excited radical ions are recognized by many researchers based on product analysis studies conducted around 1980. For cases involving fluorescent excited radical ions, lifetime measurements provide information on excited states, and they sometimes lead to confusion owing to emissive byproducts resulting from their higher reactivities. Nanosecond laser flash photolysis studies provide evidence of the reactions of excited radical ions, and analyses of their kinetics reveal properties such as their excited-state lifetimes despite an indirect manner. Recent femtosecond laser flash photolysis studies provide detailed pictures of excited radical ions, though such studies are few. Furthermore, studies on dyad or triad systems, including excited radical ions, show electron transfer dynamics and disclose characteristics of excited radical ions that differ from those in neutral states. Larger electronic coupling and smaller dumping factor are reported as important characteristics of electron transfer systems of excited radical ions. These systematic studies on excited radical ions demonstrate their suitability for applications.

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  • Strategies for development of optogenetic systems and their applications
    Publication date: March 2017
    Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 30

    Author(s): M. Endo, T. Ozawa

    It has become clear that biological processes are highly dynamic and heterogeneous within and among cells. Conventional analytical tools and chemical or genetic manipulations are unsuitable for dissecting the role of their spatiotemporally dynamic nature. Recently, optical control of biomolecular signaling, a technology called “optogenetics,” has gained much attention. The technique has enabled spatial and temporal regulation of specific signaling pathways both in vitro and in vivo. This review presents strategies for optogenetic systems development and application for biological research. Combinations with other technologies and future perspectives are also discussed herein. Although many optogenetic approaches are designed to modulate ion channel conductivity, we mainly examine systems that target other biomolecular reactions such as gene expression, protein translocations, and kinase or receptor signaling pathways.







  • Corrigendum to “Reaction dynamics of excited radical ions revealed by femtosecond laser flash photolysis” [J. Photochem. Photobiol. C: Photochem. Rev. 35 (2018) 25–37]
    Publication date: June 2018
    Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 35

    Author(s): Mamoru Fujitsuka, Tetsuro Majima









  • Optical characterization of chiral plasmonic nanostructures
    Publication date: September 2017
    Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 32

    Author(s): Kyle W. Smith, Stephan Link, Wei-Shun Chang

    Chiral plasmonic nanomaterials can have circular dichroism and optical rotatory dispersion effects orders of magnitude larger than those observed in ordinary chiral molecules. Understanding this fascinating class of materials has proved challenging and has motivated several research groups to develop entirely new experimental techniques for characterizing chirality driven optical properties. In this review, we first describe the classical method of circular dichroism which measures linear, far-field responses from an ensemble population. We then go on to describe several of the more recently developed methods to probe chiral nanostructures as they expand into the domains of non-linear, near-field, and single particle measurements including spatially and spectrally resolved techniques.

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  • Recent development on MoS2-based photocatalysis: A review
    Publication date: June 2018
    Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 35

    Author(s): Zizhen Li, Xiangchao Meng, Zisheng Zhang

    MoS2-based photocatalysts attract wide attention as they possess a suitable band gap for visible-light harvesting, making it a promising earth-abundant photocatalyst for hydrogen production, environmental remediation, and photosynthesis. However, the rapid recombination of photogenerated electron-hole pairs, limited quantity of active edge sites, and difficult photocatalyst separation and recycling hinder the practical application of this material. In this review, recent development of MoS2-based photocatalysts in various photocatalytic applications is summarized. In addition, possible approaches to enhance photocatalytic activity and separate photocatalysts from reaction media are discussed to provide a future direction in highly efficient photocatalyst design.

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  • Photochemistry and photo-electrochemistry on synthetic semiconducting diamond
    Publication date: June 2017
    Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 31

    Author(s): Daibing Luo, Kazuya Nakata, Akira Fujishima, Shanhu Liu

    In this short review, we discuss the photo-relative properties, photochemical and photo-electrochemical applications of synthetic diamond materials. Synthetic diamond with semiconductive nature owns outstanding ideal properties of physics and chemistry, including high hardness, a wide bandgap, very high carrier mobility, excellent chemical stability, and inherent biocompatibility, which makes diamond promising candidate used in photochemistry and photo-electrochemistry. Diamond materials show p-type or n-type properties via doping of certain elements, which can be utilized in photo-involved chemistry for photo-synthesis, photo-catalysis, solar cells, photo-electronics, and surface modification.







  • Conjugated macrocyclic materials with photoactivated optical absorption for the control of energy transmission delivered by pulsed radiations
    Publication date: June 2018
    Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 35

    Author(s): Mário J.F. Calvete, Danilo Dini

    The control of the transmission of the energy transported by optical waves is of extreme importance for the realization of those advanced technologies which require high speed of operation and fast switching. Such a task can be approached through the design and preparation of materials that possess modulable optical properties. In the present review the aspect of material science behind the realization of the effect of optical limiting, OL (or optical power limiting, OPL), will be considered focusing on those materials based on conjugated metallo-macrocycles like porphyrins, phthalocyanines and derivatives. The choice of these molecular materials for OL purposes is motivated by the fact that the optical properties of such annulated systems can be finely modulated in a controlled fashion by changing the chemical structure of the complex. These changes involve the variation of the central metal, the extent of electronic conjugation of the ring, the nature and the number of peripheral ligands, and the eventual introduction of axial ligands coordinated by a central metals with a valence higher than +2. An attempt will be made to establish relationships between the structure of the macrocyclic complex and the relative OL properties taking into account the most recent developments in the field. During this analysis we will also discuss the aspect of optically passivity, i.e. the characteristic of the OL materials of undergoing fast changes of optical properties according to an internal mechanism of self-activation.

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  • Oxygen imaging of living cells and tissues using luminescent molecular probes
    Publication date: March 2017
    Source:Journal of Photochemistry and Photobiology C: Photochemistry Reviews, Volume 30

    Author(s): Toshitada Yoshihara, Yosuke Hirakawa, Masahiro Hosaka, Masaomi Nangaku, Seiji Tobita

    Oxygen imaging of biological cells and tissues is becoming increasingly important in cell biology and in the pathophysiology of various hypoxia-related diseases. The optical oxygen-sensing method using luminescent probes provides very useful, high spatial resolution information regarding oxygen distribution in living cells and tissues. This review focuses on recent advances in biological oxygen measurements based on the phosphorescence quenching of probe molecules by oxygen, and on hypoxia-sensitive fluorescent probes. Special attention is devoted to metal complex probes, Pt(II)- and Pd(II)-porphyrins, Ru(II) complexes, and Ir(III) complexes. Current knowledge regarding the mechanism of phosphorescence quenching of metal complexes by oxygen is described in relation to the oxygen sensitivity of the probes, and recent advances in optical oxygen probes and detection techniques for intracellular and tissue oxygen measurements are reviewed, emphasizing the usefulness of chemical modifications for improving probe properties. Tissue oxygen imaging and hypoxic tumor imaging using these metal complex probes demonstrate the vast potential of optical oxygen-sensing methods using luminescent probes.







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