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Preparation and Characterization of Water-soluble ZnSe: Fe/ZnSe Quantum Dots
摘要： A chiral phosphoric acid-catalyzed kinetic resolution and desymmetrization of para-quinols operating via oxa-Michael addition was developed and subsequently subjected to mechanistic study. Good to excellent s-factors/enantioselectivities were obtained over a broad range of substrates. Kinetic studies were performed, and DFT studies favor a hydrogen bonding activation mode. The mechanistic studies provide insights to previously reported chiral anion phase transfer reactions involving chiral phosphate catalysts in combination with boronic acids.
关键词： directed reactivity,oxa-Michael addition,kinetics,asymmetric catalysis,chiral phosphoric acid,reaction mechanisms
更新于2025-09-11 14:15:04
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Construction of Novel CdS/SnNb <sub/>2</sub> O <sub/>6</sub> Heterojunctions with Enhanced Photocatalytic Degradation Activity Under Visible Light
摘要： Accelerating the photo-induced charge carrier transfer and improving charge utilization are critical for enhancing the photocatalytic activity of photocatalysts. In this work, we successfully constructed CdS/SnNb2O6 heterojunction photocatalysts by a facile hydrothermal method. The obtained CdS/SnNb2O6 heterojunction exhibited better photocatalytic performance than pristine CdS and SnNb2O6, and the photocatalytic activity of the optimal ratio sample (40 % CdS) was 3.2 and 28.5 times as high as that of the pristine CdS and SnNb2O6, respectively. On the basis of the PL spectra, transient photocurrent response, trapping experiments of the active species, and ESR results, the possible charge carrier transfer and photocatalytic mechanisms of the CdS/SnNb2O6 heterojunction photocatalyst have been illustrated. We demonstrated that the combination of CdS and SnNb2O6 can greatly boost the photo-generated charge carrier separation and therefore enhance the photocatalytic activity. Our work opens up a new insight for development of semiconductor photocatalysts with high efficiency.
关键词： Heterojunctions,Photocatalysis,Charge separation,Reaction mechanisms,Semiconductors
更新于2025-09-10 09:29:36
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Mechanistic insights into light-activated catalysis for water oxidation
摘要： The development of catalysts for water oxidation to oxygen has been the subject of intense investigation in the last decade. In parallel to the search for high catalytic performance, many works have focused on the mechanistic analysis of the process. In this perspective, the oxidation of water through light-assisted cycles composed of an electron acceptor (EA), a photosensitizer (PS), and a water oxidation catalyst (WOC) can provide insightful and complementary information with respect to the use of chemical oxidants or to electrochemical techniques. In this microreview, we discuss the mechanistic aspects of the EA/PS/WOC photoactivated cycles, and in particular: (i) the general elementary steps; (ii) the required features and the nature of the PS employed; (iii) the electron transfer processes and kinetics from the WOC to PS+ (hole scavenging); (iv) the detrimental quenching of the PS by the WOC and the alternative mechanistic routes; (v) the identification of WOC intermediates and, finally, (vi) the transposition of the above processes into a dye-sensitized photoanode embedding a WOC.
关键词： reaction mechanisms,intermediates,water oxidation,Electron transfer,photocatalysis
更新于2025-09-04 15:30:14