Electrosynthesis and characterization of lead dioxide–perfluorobutanesulfonate composite

The effect of potassium perfluorobutanesulfonate on the kinetic features of electrodeposition of lead dioxide from methanesulfonate electrolytes has been investigated. The introduction of C4F9SO3K into the lead dioxide deposition electrolyte leads to insignificant inhibition of the Pb2+ electrooxidation process, while the mechanism of the process does not change. A composite coating is formed upon deposition of coatings from electrolytes containing surfactants. The surface of a composite material consists of a mixture of clearly expressed large crystalline blocks with sharp angles and small crystals. Energy dispersive X-ray analysis revealed the satisfactory distribution of modifying elements in the entire sample bulk, and not only on the coating surface. It was shown that the electrocatalytic activity of lead dioxide–perfluorobuthanesulfonate composite differs from the undoped sample. The oxygen evolution reaction slightly decelerates on a PbO2–C4F9SO3K composite. The Tafel slopes in 1 M HClO4 calculated from these curves plotted in semilogarithmic coordinates are 136 and 145 mV dec–1 for undoped sample and lead dioxide-surfactant composite, respectively. The reaction of electrochemical oxidation of p-chlorophenol is characterized by the pseudo-first order kinetics with respect to the initial compound. The use of doped C4F9SO3K lead dioxide as an anode leads to the inhibition of the process of oxygen evolution and an almost one and a half higher rate of electrochemical conversion of 4-chlorophenol to aliphatic compounds.

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Modeling of Carbonyl/Ammonium Sulfate Aqueous Brown Carbon Chemistry via UV/Vis Spectral Decomposition

Atmosphere ◽

10.3390/atmos11040358 ◽

2020 ◽

Vol 11 (4) ◽

pp. 358 ◽

Cited By ~ 3

Author(s):

Mengjie Fan ◽

Shiqing Ma ◽

Nahin Ferdousi ◽

Ziwei Dai ◽

Joseph L. Woo

Keyword(s):

Climate Forcing ◽

Reaction Products ◽

Brown Carbon ◽

Reaction Systems ◽

Reaction Rate Constants ◽

Kinetic Information ◽

First Order Kinetics ◽

Aggregate Effect ◽

Light Absorbance

The proper characterization of aqueous brown carbon (BrC) species, their formation, and their light absorbance properties is critical to understanding the aggregate effect that they have on overall atmospheric aerosol climate forcing. The contribution of dark chemistry secondary organic aerosol (SOA) products from carbonyl-containing organic compounds (CVOCs) to overall aqueous aerosol optical properties is expected to be significant. However, the multiple, parallel pathways that take place within CVOC reaction systems and the differing chromophoricity of individual products complicates the ability to reliably model the chemical kinetics taking place. Here, we proposed an alternative method of representing UV-visible absorbance spectra as a composite of Gaussian lineshape functions to infer kinetic information. Multiple numbers of curves and different CVOC/ammonium reaction systems were compared. A model using three fitted Gaussian curves with magnitudes following first-order kinetics achieved an accuracy within 65.5% in the 205–300-nm range across multiple organic types and solution aging times. Asymmetrical peaks that occurred in low-200-nm wavelengths were decomposed into two overlapping Gaussian curves, which may have been attributable to different functional groups or families of reaction products. Component curves within overall spectra exhibited different dynamics, implying that the utilization of absorbance at a single reference wavelength to infer reaction rate constants may result in misrepresentative kinetics for these systems.

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Preparation and characterization of lead dioxide electrode with three-dimensional porous titanium substrate for electrochemical energy storage

Electrochimica Acta ◽

10.1016/j.electacta.2014.06.175 ◽

2014 ◽

Vol 139 ◽

pp. 209-216 ◽

Cited By ~ 24

Author(s):

Wenli Zhang ◽

Haibo Lin ◽

Haishen Kong ◽

Haiyan Lu ◽

Zhe Yang ◽

...

Keyword(s):

Energy Storage ◽

Lead Dioxide ◽

Three Dimensional ◽

Titanium Substrate ◽

Porous Titanium ◽

Electrochemical Energy Storage ◽

Lead Dioxide Electrode ◽

Electrochemical Energy

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Synthesis and Characterization of Some Novel Homo- and Hetero-Diradicals of Hydrazyl and Nitroxide Type

Australian Journal of Chemistry ◽

10.1071/ch06469 ◽

2007 ◽

Vol 60 (3) ◽

pp. 173 ◽

Cited By ~ 4

Author(s):

Petre Ionita ◽

Floriana Tuna ◽

Marius Andruh ◽

Titus Constantinescu ◽

Alexandru T. Balaban

Keyword(s):

Free Radical ◽

Potassium Permanganate ◽

Lead Dioxide ◽

Magnetic Behaviour ◽

Synthesis And Characterization ◽

Stable Free Radical ◽

Ms Analysis ◽

New Compounds

Starting from the well known stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH; 2a) and its congener 2,2-diphenyl-1-(4-cyano-2,6-dinitrophenyl)hydrazyl 2b, or from their reduced hydrazine counterparts 1a,b, it was possible to obtain the p-quinonoid compounds 4a,b by oxidation with ceric (Ce4+) sulfate, which by reduction gave the corresponding hydroxyl derivatives 2-phenyl-2-(4-hydroxyphenyl)-1-picrylhydrazine 5a or 2-phenyl-2-(4-hydroxyphenyl)-1-(4-cyano-2,6-dinitrophenyl)hydrazine 5b. These hydroxyl derivatives (5a,b) react with 4-carboxy-TEMPO or 2,2-diphenyl-1-(4-carboxy-2,6-dinitrophenyl)hydrazine to form the corresponding esters 6a,b or 8a,b. These esters (6a,b and 8a,b) lead to the hybrid hetero diradicals (nitroxide–hydrazyl type) 7a,b or homo biradicals (hydrazyl–hydrazyl type) 9a,b by oxidation with lead dioxide or potassium permanganate. The new compounds were characterized by UV-vis, NMR, EPR, and MS analysis, and their magnetic behaviour was investigated.

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Non-photochemical quenching of chlorophyll a fluorescence: early history and characterization of two xanthophyll-cycle mutants of Chlamydomonas reinhardtii

Functional Plant Biology ◽

10.1071/fp02061 ◽

2002 ◽

Vol 29 (10) ◽

pp. 1141 ◽

Cited By ~ 28

Author(s):

Govindjee ◽

Manfredo J. Seufferheld

Keyword(s):

Chlamydomonas Reinhardtii ◽

Oxygen Evolution ◽

Xanthophyll Cycle ◽

Photochemical Quenching ◽

Chl A ◽

Fluorescence Transient ◽

Chl A Fluorescence ◽

Non Photochemical Quenching

This paper deals first with the early, although incomplete, history of photoinhibition, of 'non-QA-related chlorophyll (Chl) a fluorescence changes', and the xanthophyll cycle that preceded the discovery of the correlation between non-photochemical quenching of Chl a fluorescence (NPQ) and conversion of violaxanthin to zeaxanthin. It includes the crucial observation that the fluorescence intensity quenching, when plants are exposed to excess light, is indeed due to a change in the quantum yield of fluorescence. The history ends with a novel turn in the direction of research — isolation and characterization of NPQ xanthophyll-cycle mutants of Chlamydomonas reinhardtii Dangeard and Arabidopsis thaliana (L.) Heynh., blocked in conversion of violaxanthin to zeaxanthin, and zeaxanthin to violaxanthin, respectively. In the second part of the paper, we extend the characterization of two of these mutants (npq1, which accumulates violaxanthin, and npq2, which accumulates zeaxanthin) through parallel measurements on growth, and several assays of PSII function: oxygen evolution, Chl a fluorescence transient (the Kautsky effect), the two-electron gate function of PSII, the back reactions around PSII, and measurements of NPQ by pulse-amplitude modulation (PAM 2000) fluorimeter. We show that, in the npq2 mutant, Chl a fluorescence is quenched both in the absence and presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). However, no differences are observed in functioning of the electron-acceptor side of PSII — both the two-electron gate and the back reactions are unchanged. In addition, the role of protons in fluorescence quenching during the 'P-to-S' fluorescence transient was confirmed by the effect of nigericin in decreasing this quenching effect. Also, the absence of zeaxanthin in the npq1 mutant leads to reduced oxygen evolution at high light intensity, suggesting another protective role of this carotenoid. The available data not only support the current model of NPQ that includes roles for both pH and the xanthophylls, but also are consistent with additional protective roles of zeaxanthin. However, this paper emphasizes that we still lack sufficient understanding of the different parts of NPQ, and that the precise mechanisms of photoprotection in the alga Chlamydomonas may not be the same as those in higher plants.

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Preparation and Application of Lead Dioxide Electrode for Zinc Electrolysis

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.785-786.1125 ◽

2013 ◽

Vol 785-786 ◽

pp. 1125-1129

Author(s):

Xiao Yong Yang ◽

Pei Xian Zhu ◽

Yun Sen Si

Keyword(s):

Surface Characterization ◽

Catalytic Properties ◽

Lead Dioxide ◽

Manufacturing Cost ◽

X Ray Diffraction ◽

Simulation Test ◽

X Ray ◽

Zinc Smelter ◽

Lead Dioxide Electrode

According to the process of anodic oxygen evolution in sulfate system for zinc electrolysis,Ti-base lead dioxide electrode can be prepared to use in this case.The surface characterization of the electrode was studied by Scanning electron microscopy(SEM) and X-ray diffraction(XRD).The electrode lifetime was tested in 1mol/L H2SO4solution at 60°C,and the electro-catalytic properties was examined by polarization curves.Then these samples was enlarged and simulation test was conducted at Mengzi marriage zinc smelter in Yunnan.The results show that the electro-catalytic properties is better and the electrodes lifetime is longer compared to the traditional lead electrode.Moreover,it has a significant effect in reducing energy consumption, manufacturing cost and improving the production and grade of zinc.

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(Invited) High-Throughput Synthesis and Characterization of Fe-Based Oxygen Reduction Reaction Electrocatalysts and Perovskite Oxide Oxygen Evolution Electrocatalysts

ECS Meeting Abstracts ◽

10.1149/ma2021-02441345mtgabs ◽

2021 ◽

Vol MA2021-02 (44) ◽

pp. 1345-1345

Author(s):

Deborah J. Myers ◽

Magali Ferrandon ◽

Ahmed A Farghaly ◽

Xiaoping Wang ◽

Jaehyung Park ◽

...

Keyword(s):

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Oxygen Evolution ◽

High Throughput ◽

Reduction Reaction ◽

Perovskite Oxide ◽

Synthesis And Characterization

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ATRP Synthesis and Characterization of μ,αω-allyl-terminated Macromonomers as Precursors for End-linked Gels and Hydrogels

MRS Proceedings ◽

10.1557/proc-774-o1.8 ◽

2003 ◽

Vol 774 ◽

Author(s):

Lucy Vojtova ◽

Nicholas J. Turro ◽

Jeffrey T. Koberstein

Keyword(s):

Molecular Weight ◽

Monomer Concentration ◽

Monomer Conversion ◽

Catalyst System ◽

Linear Increase ◽

Butyl Methacrylate ◽

First Order Kinetics ◽

Significant Difference ◽

Ft Ir

AbstractSynthesis of α,ω-allyl-terminated telechelic macromonomers based on poly(tert-butyl methacrylate) (poly(t-BMA)) and poly(methacrylic acid) (poly(MAA)) was studied with the aim of preparing end-linked gels and hydrogels. Low molecular weight α-allyl-terminated poly(t-BMA) macromonomers with narrow polydispersities (Mw/Mn = 1.16) were synthesized via controlled atom transfer radical polymerization (ATRP) using a Cu(I)Br/N,N,N',N',N',N'-hexamethyltriethylenetetraamine catalyst system in conjunction with an allyl-2-bromoisobutyrate as the functional initiator. The polymerizations exhibited a linear increase of molecular weight in direct proportion to the monomer conversion and first-order kinetics with respect to monomer concentration. No significant difference was found between using polar or non-polar solvents (tetrahydrofuran or benzene, respectively). Optimization of reaction conditions to obtain the highest degree of active terminal bromine is discussed. Quenching the ATRP reaction with allyltributyltin yielded α,ω-allyl-terminated poly(t-BMA) macromonomers by replacing the terminal bromine with ω-allyl functional group. Poly(MAA) macromonomers were prepared by deprotection of the tert-butyl group from α,ω-allyl-terminated poly(t-BMA) macromonomers using concentrated trifluoroacetic acid at room temperature. Successful synthetic steps were confirmed by 1H NMR, FT-IR and MALDI-TOF MS analyses. The α,ω-allyl-terminated macromonomers were proven to be candidates for further polymerization by forming end-linked, non-soluble gels.

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