Azo compounds (AZO), such as azobenzene, are classic organic electrode materials featuring a redox potential close to Zn/Zn. Recent studies show that azobenzene could work as a cathode in aqueous zinc-ion batteries (AZIBs), providing a voltage output of around 0.7 V. However, the energy storage mechanism of AZO cathodes in AZIBs remains unclear, and their practical usage in AZIBs is hindered by the low voltage. In this study, azopyridine isomers, the hydrophilic analogues of azobenzene, were adopted as cathodes for AZIBs, and the energy storage mechanism was unveiled through aqueous electrochemical studies. Through electrochemical characterizations and theoretical computations, we reveal that both the electron-withdrawing effect of the pyridyl group and the H-involved -N = N-/-NH-NH- redox reaction uplift the redox potential of the azopyridine cathodes. These findings led to the first AZO-based AZIB, providing a voltage output of 1.4 V. The proposed air-stable AZIBs deliver a high energy/power density and a capacity of around 200 mAh g. This work discovers different azopyridine electrochemistry in aqueous and organic electrolytes and enabling AZIBs to outperform its competitors from the AZO family.
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http://dx.doi.org/10.1021/acsami.4c09801 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720.
Polysaccharide monooxygenase (PMO) catalysis involves the chemically difficult hydroxylation of unactivated C-H bonds in carbohydrates. The reaction requires reducing equivalents and will utilize either oxygen or hydrogen peroxide as a cosubstrate. Two key mechanistic questions are addressed here: 1) How does the enzyme regulate the timely and tightly controlled electron delivery to the mononuclear copper active site, especially when bound substrate occludes the active site? and 2) How does this electron delivery differ when utilizing oxygen or hydrogen peroxide as a cosubstrate? Using a computational approach, potential paths of electron transfer (ET) to the active site copper ion were identified in a representative AA9 family PMO from (PMO9E).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 10120, Thailand.
A single-component flavin-dependent halogenase, AetF, has emerged as an attractive biocatalyst for catalyzing halogenation. However, its flavin chemistry remains unexplored and cannot be predicted due to its uniqueness in sequence and structure compared to other flavin-dependent monooxygenases. Here, we investigated the flavin reactions of AetF using transient kinetics.
View Article and Find Full Text PDFJ Fish Biol
January 2025
Laboratório de Biologia Aquática Aplicada, Universidade Federal da Grande Dourados, Dourados, Brazil.
The diet of indicator fish species plays a crucial role in assessing ecosystem health. This study evaluated streams with and without urban influences, focusing on abiotic parameters and the trophic ecology of Psalidodon fasciatus and Piabina argentea. Forested streams exhibited higher redox potential, dissolved oxygen, transparency, and depth, whereas urban streams had higher temperatures, greater widths, and increased levels of total dissolved solids, conductivity, total coliforms, and thermotolerant coliforms.
View Article and Find Full Text PDFNaunyn Schmiedebergs Arch Pharmacol
January 2025
Postgraduate Program in Health Sciences (PPGCS), Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM), Diamantina, Brazil.
The progression of periodontal disease (PD) involves the action of oxidative stress mediators. Antioxidant agents may potentially attenuate the development of this condition. Thus, we aimed to evaluate the effects of different doses of humic acid (HA), extracted from biomass vermicomposting, on redox status and parameters related to PD progression in rats.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
KU Leuven: Katholieke Universiteit Leuven, Chemistry, BELGIUM.
Understanding the impact of oxidative modification on protein structure and functions is essential for developing therapeutic strategies to combat macromolecular damage and cell death. However, selectively inducing oxidative modifications in proteins remains challenging. Herein we demonstrate that [V6O13{(OCH2)3CCH2OH}2]2- (V6-OH) hybrid metal-oxo cluster can be used for selective protein oxidative cleavage and modifications.
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