The origin of the hysteresis in cyclic voltammetric response of alkaline methanol electrooxidation

2020 ◽  
Vol 22 (29) ◽  
pp. 16648-16654
Author(s):  
Theresa Haisch ◽  
Fabian Kubannek ◽  
Lialia Nikitina ◽  
Igor Nikitin ◽  
Sabine Pott ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Methanol Electrooxidation ◽  
Electrochemical Measurements ◽  
Cyclic Voltammetric ◽  
Platinum Oxides

The origin of the hysteresis is investigated by electrochemical measurements, in situ IR spectroscopy and simulations. It is concluded that the formation of platinum oxides rather than the formation of blocking intermediates causes the hysteresis.

The Nature of Chemisorbed CO2 in Zeolite A

2019 ◽  
Author(s):  
Przemyslaw Rzepka ◽  
Zoltán Bacsik ◽  
Andrew J. Pell ◽  
Niklas Hedin ◽  
Aleksander Jaworski
Keyword(s):  
Solid State ◽  
Ir Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Surface Coverage ◽  
Gas Mixtures ◽  
Mas Nmr ◽  
Significant Fraction ◽  
Zeolite A

Formation of CO<sub>3</sub><sup>2-</sup> and HCO<sub>3</sub><sup>-</sup> species without participation of the framework oxygen atoms upon chemisorption of CO<sub>2</sub> in zeolite |Na<sub>12</sub>|-A is revealed. The transfer of O and H atoms is very likely to have proceeded via the involvement of residual H<sub>2</sub>O or acid groups. A combined study by solid-state <sup>13</sup>C MAS NMR, quantum chemical calculations, and <i>in situ</i> IR spectroscopy showed that the chemisorption mainly occurred by the formation of HCO<sub>3</sub><sup>-</sup>. However, at a low surface coverage of physisorbed and acidic CO<sub>2</sub>, a significant fraction of the HCO<sub>3</sub><sup>-</sup> was deprotonated and transformed into CO<sub>3</sub><sup>2-</sup>. We expect that similar chemisorption of CO<sub>2</sub> would occur for low-silica zeolites and other basic silicates of interest for the capture of CO<sub>2</sub> from gas mixtures.

Catalytic activity of rhodium(I) complexes containing (ω-trimethylsilylalkyl)diphenylphosphines

1980 ◽  
Vol 45 (8) ◽  
pp. 2219-2223 ◽  
Author(s):  
Marie Jakoubková ◽  
Martin Čapka
Keyword(s):  
Catalytic Activity ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Electron Density ◽  
Phosphorus Atom ◽  
Proton Acceptor ◽  
Trimethylsilyl Group ◽  
Kinetics Of

Kinetics of homogenous hydrogenation of 1-heptene catalysed by rhodium(I) complexes prepared in situ from μ,μ'-dichloro-bis(cyclooctenerhodium) and phosphines of the type RP(C6H5)2 (R = -CH3, -(CH2)nSi(CH3)3; n = 1-4) have been studied. The substitution of the ligands by the trimethylsilyl group was found to increase significantly the catalytic activity of the complexes. The results are discussed in relation to the electron density on the phosphorus atom determined by 31P NMR spectroscopy and to its proton acceptor ability determined by IR spectroscopy.

In Situ IR Spectroscopy for Following the Copolymerization of CO2and Epoxides

2014 ◽  
Vol 86 (9) ◽  
pp. 1627-1628
Author(s):  
K. Böhm ◽  
W. Leitner ◽  
T. E. Müller
Keyword(s):  
Ir Spectroscopy ◽  
In Situ Ir ◽  
In Situ Ir Spectroscopy

Activated Nitrogen-Enriched Carbon/Reduced Expanded Graphite Composites for Supercapacitors

2011 ◽  
Vol 211-212 ◽  
pp. 440-444 ◽  
Author(s):  
Shu Hui Tong ◽  
Chuan Li Qin ◽  
Zheng Jin ◽  
Xue Song Wang ◽  
Xu Duo Bai
Keyword(s):  
Electrode Material ◽  
In Situ Polymerization ◽  
Expanded Graphite ◽  
Mechanical Mixture ◽  
Electrochemical Measurements ◽  
Electrochemical Performances ◽  
Cycle Stability ◽  
Symmetric Supercapacitor ◽  
Graphite Composites

Activated nitrogen-enriched carbon/reduced expanded graphite composites (ANC/REG-c) with different composite ratio were prepared by in-situ polymerization, carbonization, activation and reduction of aniline and expanded graphite. These were characterized by XPS, SEM and electrochemical measurements. XPS shows that N atoms exist in the ANC and ANC/REG-c. Compared to mechanical mixture of ANC and REG(ANC/REG-m), ANC/REG-c shows lower resistance and higherCp1(185.4 F/g) vs 124.3 F/g of ANC/REG-m measured by CV due to the introduction of the composite sturcture. When the composite ratio of ANC/REG-c is 6:1, the ANC/REG-c shows the highestCp1(264.0 F/g) and its symmetric supercapacitor also shows the best synthetical electrochemical performances. The optimal supercapacitor presents good cycle stability. ANC/REG-c is a suitable electrode material for supercapacitors.

Spontaneous Rapid Growth of Triruthenium Cluster Multilayers on Gold Surface. Cyclic Voltammetric In Situ Monitoring and AFM Characterization

2008 ◽  
Vol 37 (6) ◽  
pp. 576-577 ◽  
Author(s):  
Takayuki Michi ◽  
Masaaki Abe ◽  
Satoru Takakusagi ◽  
Masako Kato ◽  
Kohei Uosaki ◽  
...  
Keyword(s):  
Rapid Growth ◽  
Gold Surface ◽  
In Situ Monitoring ◽  
Cyclic Voltammetric

scholarly journals In Situ IR Spectroscopy of Mesoporous Silica Films for Monitoring Adsorption Processes and Trace Analysis

2018 ◽  
Vol 1 (12) ◽  
pp. 7083-7091 ◽  
Author(s):  
Bettina Baumgartner ◽  
Jakob Hayden ◽  
Andreas Schwaighofer ◽  
Bernhard Lendl
Keyword(s):  
Ir Spectroscopy ◽  
Mesoporous Silica ◽  
Trace Analysis ◽  
Silica Films ◽  
In Situ Ir ◽  
Adsorption Processes ◽  
In Situ Ir Spectroscopy

scholarly journals Cobalt(II) complexes with aromatic carboxylates and N-functionalized cyclam bearing 2-pyridylmethyl pendant arms

2005 ◽  
Vol 70 (8-9) ◽  
pp. 1121-1129 ◽  
Author(s):  
Gordana Vuckovic ◽  
V. Stanic ◽  
Sofija Sovilj ◽  
M. Antonijevic-Nikolic ◽  
J. Mrozynski
Keyword(s):  
Cyclic Voltammetry ◽  
Ir Spectroscopy ◽  
Chair Conformation ◽  
Trans Position ◽  
Cyclic Voltammetric ◽  
Aromatic Carboxylates ◽  
Elemental Analyses ◽  
Electrical Conductivities ◽  
Pendant Arms ◽  
Voltammetric Measurements

Novel binuclear Co(II) complexeswithN-functionalized cyclam N,N?,N",N???-tetrakis( 2-pyridylmethyl)tetraazacyclotetradecane (tpmc) and one of the aromatic monoor dicarboxylato ligands (benzoate, phthalate or isophthalate ions) were prepared. They were analyzed and studied by elemental analyses (C, H, N), electrical conductivities, VIS and IR spectroscopy andmagnetic as well as cyclic voltammetric measurements. In [Co2(C6H5COO)2tpmc]ClO4)2.3H2O, the benzoate ligands are most probably coordinated as chelates in the trans-position to each Co(II) and the macrocycle adopts a chair conformation. In the complexes [Co2(Y)tpmc]ClO4)2.zH2O, (Y = phthalate or i-phthalate dianizon, z = 2; 4) it is proposed that the isomeric dicarboxylates are bonded combined as bridges and chelates. The composition and the assumed geometries of the complexes are compared with the, earlier reported, corresponding Cu(II) complexes. Cyclic voltammetry measurements showed that the compounds are electrochemically stable.

scholarly journals Monitoring the Interfacial Polymerization of Piperazine and Trimesoyl Chloride with Hydrophilic Interlayer or Macromolecular Additive by in-situ FT-IR Spectroscopy

2019 ◽  
Author(s):  
Xi Yang
Keyword(s):  
Ir Spectroscopy ◽  
Reaction Rate ◽  
Interfacial Polymerization ◽  
Reaction System ◽  
Reaction Rates ◽  
Water Permeation ◽  
Ft Ir ◽  
Trimesoyl Chloride ◽  
Ft Ir Spectroscopy

The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize the nanofiltration (NF) membrane. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies are applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer; (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in-situ FT-IR spectroscopy was firstly used to monitor the IP reaction of PIP/TMC reaction system, with hydrophilic interlayers or macromolecular additives. Moreover, we study the formed polyamide layer growth on the substrate, in a real-time manner. The in-situ FT-IR experimental results confirm that the IP reaction rates are effectively suppressed and the formed polyamide thickness reduces from 138&plusmn;24 nm to 46&plusmn;2 nm. Furthermore, the optimized NF membrane with excellent performance are consequently obtained, which include the boosted water permeation flux about 141~238 (L&middot;m2&middot;h/MPa) and superior salt rejection of Na2SO4 &gt; 98.4%.

Ethylene polymerization on a SiH4-modified Phillips catalyst: detection of in situ produced α-olefins by operando FT-IR spectroscopy

2012 ◽  
Vol 14 (7) ◽  
pp. 2239 ◽  
Author(s):  
Caterina Barzan ◽  
Elena Groppo ◽  
Elsje Alessandra Quadrelli ◽  
Vincent Monteil ◽  
Silvia Bordiga
Keyword(s):  
Ir Spectroscopy ◽  
Ethylene Polymerization ◽  
Phillips Catalyst ◽  
Ft Ir ◽  
Ft Ir Spectroscopy
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