The Role of the Double Layer for the Pseudocapacitance of the Hydrogen Adsorption on Platinum

Pseudocapacitances such as the hydrogen adsorption on platinum (HAoPt) are associated with faradaic chemical processes that appear as capacitive in their potentiodynamic response, which was reported to result from the kinetics of adsorption processes. This study discusses an alternative interpretation of the partly capacitive response of the HAoPt that is based on the proton transport of ad- or desorbed hydrogen in the double layer. Potentiodynamic perturbations of equilibrated surface states of the HAoPt lead to typical double layer responses with the characteristic resistive-capacitive relaxations that overshadow the fast adsorption kinetics. A potential-dependent double layer representation by a dynamic transmission line model incorporates the HAoPt in terms of capacitive contributions and can computationally reconstruct the charge exchanged in full range cyclic voltammetry data. The coupling of charge transfer with double layer dynamics displays a novel physicochemical theory to explain the phenomenon of pseudocapacitance and the mechanisms in thereon based supercapacitors.

Promotion and Tuning of the Electrochemical Reduction of Hetero- and Homobimetallic Zinc Complexes

Compounds containing multiple metals attract significant interest due to the useful redox and reactivity properties of such species. Here, the electrochemical properties of a family of macrocyclic complexes that feature a zinc(II) center paired with a second redox-inactive metal cation in heterobimetallic (Na+, Ca2+, Nd3+, Y3+) motifs or a homobimetallic (Zn2+) motif have been investigated. The new complexes were prepared via a divergent strategy, isolated, and structurally characterized by single-crystal X-ray diffraction (XRD) analysis. XRD results show that the structure of the complexes is modulated by the identity of the incorporated secondary metal ions. Cyclic voltammetry data reveal that ligand-centered reduction is promoted in the bimetallic complexes and that the paired metal ions synergistically influence the redox properties of the complexes. Similar to prior work from our group and others, the bimetallic complexes containing stronger Lewis acids undergo more significant reduction potential shifts; contrasting with prior work on complexes containing redox-active metals, however, the zinc(II) complexes studied here display faster electron transfer (as judged by lower reorganization energies, λ) when incorporating di- or tri-valent Lewis acids in contrast to monovalent (and more weakly acidic) sodium. The quantified trends in these data offer insights that help distinguish metal- versus ligand-centered reduction of bimetallic complexes.<br>

Promotion and Tuning of the Electrochemical Reduction of Hetero- and Homobimetallic Zinc Complexes

Compounds containing multiple metals attract significant interest due to the useful redox and reactivity properties of such species. Here, the electrochemical properties of a family of macrocyclic complexes that feature a zinc(II) center paired with a second redox-inactive metal cation in heterobimetallic (Na+, Ca2+, Nd3+, Y3+) motifs or a homobimetallic (Zn2+) motif have been investigated. The new complexes were prepared via a divergent strategy, isolated, and structurally characterized by single-crystal X-ray diffraction (XRD) analysis. XRD results show that the structure of the complexes is modulated by the identity of the incorporated secondary metal ions. Cyclic voltammetry data reveal that ligand-centered reduction is promoted in the bimetallic complexes and that the paired metal ions synergistically influence the redox properties of the complexes. Similar to prior work from our group and others, the bimetallic complexes containing stronger Lewis acids undergo more significant reduction potential shifts; contrasting with prior work on complexes containing redox-active metals, however, the zinc(II) complexes studied here display faster electron transfer (as judged by lower reorganization energies, λ) when incorporating di- or tri-valent Lewis acids in contrast to monovalent (and more weakly acidic) sodium. The quantified trends in these data offer insights that help distinguish metal- versus ligand-centered reduction of bimetallic complexes.<br>

Synthesis and Electrochemical Properties of Nanocrystalline Nickel Molybdate

We have obtained nanocrystalline hydrate and alpha phase of nickel molybdate by a hydrothermal technique. On the basis of the obtained cyclic voltammetry data, we have evaluated the contribution of faradaic and non-faradaic processes to the total capacitance of molybdates under study. It was found that the specific capacitance of hydrate NiMoO4·H2O is 621 F/g at a scan rate of 1 mV / s and the specific capacitance of the α-NiMoO4 is 281 F/g. Cathodes for hybrid supercapacitors were formed on the basis of the obtained nickel molybdates. As a result of electrochemical studies, it was found that the specific capacitance of hybrid supercapacitor based on NiMoO4·H2O/C was 256 F/g at the current of 0.2 A/g, while the specific energy was 80 W h/kg and specific power – 304 W/kg and these results are higher below in the α-NiMoO4 /C-based hybrid supercapacitor.

Chemical Space Mapping for Multicomponent Gas Mixtures

In our manuscript, we present our protocol for data processing to mitigate the effects of interfering analytes on the identification of the chemical species detected by sensors. Considering NO2 and CO2, we designed electrochemical sensors whose response yielded the cyclic voltammetry data that we analyzed to classify single-species components and their mixtures using a data-driven approach to generate a chemical space where their mixtures can be deconvoluted.<br>

Chemical Space Mapping for Multicomponent Gas Mixtures

In our manuscript, we present our protocol for data processing to mitigate the effects of interfering analytes on the identification of the chemical species detected by sensors. Considering NO2 and CO2, we designed electrochemical sensors whose response yielded the cyclic voltammetry data that we analyzed to classify single-species components and their mixtures using a data-driven approach to generate a chemical space where their mixtures can be deconvoluted.<br>

Estimation of Cyclic Voltammetry Data for Srcl₂, Cacl₂ and Their Interaction with Ceftriaxone Sodium Salt in KNO₃ Using Palladium Working Electrode

The cyclic voltammetry data for the redox reaction for strontium chloride and calcium chloride in 0.1M KNO3 pollution were estimated. New palladium electrode was prepared and used as working electrode. Palladium electrode has already redox waves which used as analytical method for the estimation of calcium and strontium in solutions. Also, interaction of both strontium and calcium ions with drug ceftriaxone sodium salt was studied and the data obtained are used for the analytical evaluation for both calcium and strontium. The different kinetic and thermodynamic data was evaluated for the two kinds of ions alone and in the presence of ceftriaxone sodium salt and their data were discussed.

Unusual chemistry of Cu(ii) salan complexes: synthesis, characterization and superoxide dismutase activity

Cu(ii)-salan complexes: structural and spectral characterization, solvent assisted ring cleavage and correlation of superoxide dismutase activity with cyclic voltammetry data and steric effects.

The electron as a probe to measure the thickness distributions of electroactive films

A theoretical model combined to an experimental study shows that the morphology of electron conducting films can be quantified directly from the analysis of cyclic voltammetry data.

Electrochemical Mechanism for the Preparation of Fe-Si Alloys by Melts Electrodeposition

The melts dissolution characteristics and reaction process during the preparation of Fe-Si alloys by the melts electrochemical method were studied. The thermodynamic calculations and experimental results showed that the solubility of SiO2 in KCl-NaCl-NaF melts was 0.24 mas% at 1073 K. The cyclic voltammetry data showed that the reduction of SiO2 on a Pt electrode was a one-step electron process; when SiO2 accounted for 0.24 mas% of the NaCl-KCl-NaF melts, the Fe-Si alloy was prepared by electrodeposition at 1073 K. When the deposition time was 30 min, Fe3Si was formed.