Multivariate statistical analysis of chemical and electrochemical oscillators for an accurate frequency selection

Kitagaki, Bianca Tieme; Pinto, Maria Rodrigues; Queiroz, Adriana Corrêa de; Breitkreitz, Márcia Cristina; Rossi, Federico; Nagao, Raphael

doi:10.1039/c9cp01998g

Cited by 10 publications

(10 citation statements)

References 94 publications

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“…Small amplitudes, between 0.05 and 0.10 V are seen in extreme conditions of pH and current density, on the far right in the diagram. For the Cu(II)–tartrate system, the oscillation amplitudes are substantially inferior, ranging from 0.04 and 0.10 V. These irregularities in the diagrams are not related to experimental deviations (great sensitivity of these systems to the experimental parameters), but to synergistic effects that might exist, as stated previously . In general, as both current and pH increase, the oscillations have increasingly smaller periods and amplitudes until nonoscillating or steady-state conditions are reached.…”

Section: Resultssupporting

confidence: 49%

“…For example, the frequency of the oscillatory electrodeposition of Cu/Cu 2 O in lactate solution was shown to be quadratically dependent on the pH and j . Consequently, it is not reflected in a usual and possibly expected proportional response . These nonlinear dependences can be observed in Figures and , in which the increase of the pH and the applied current density does not always promote the decrease of the oscillation period (Figures c and c).…”

Section: Resultsmentioning

confidence: 90%

“…For the Cu(II)−tartrate system, the oscillation amplitudes are substantially inferior, ranging from 0.04 and 0.10 V. These irregularities in the diagrams are not related to experimental deviations (great sensitivity of these systems to the experimental parameters), but to synergistic effects that might exist, as stated previously. 26 In general, as both current and pH increase, the oscillations have increasingly smaller periods and amplitudes until nonoscillating or steady-state conditions are reached. As observed, the effect of shortening the oscillation period by increasing the solution alkalinity was previously reported by Switzer et al 22 stating that the current density has little influence on the period.…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly, most of these synthetic experiments of nanostructured Cu/Cu 2 O multilayers were carried out with lactate − as a complexing agent to prevent the precipitation of copper as hydroxides in the basic solution. Some of them also utilized tartrate , or even citrate anions. − Although few studies combine two different ligands, as reported by Leopold et al, , no detailed discussion about the influence of the chemical nature of the ligands on the oscillatory electrodeposition of Cu/Cu 2 O has been investigated so far.…”

Section: Introductionmentioning

confidence: 99%

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Influence of the Ligands in Cu(II) Complexes on the Oscillatory Electrodeposition of Cu/Cu₂O

et al. 2020

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Oscillatory electrodeposition reactions have been utilized to create nanostructured materials under the microscale and nanoscale. This alternative method of synthesis, when compared to the traditional step-by-step synthesis procedure, takes advantage of the self-organizing processes that do not require any external control or template-based support, resulting in materials with higher complexity in terms of structure and composition. Nanolayers made of Cu and semiconductor composites, such as Cu/Cu2O, can be finely tuned by controlling ordinary period-one oscillations in the cathodic deposition. As the reaction media is alkaline, a complexing agent is commonly added in the solution to prevent the precipitation of the copper ions as hydroxides. Lactate and tartrate molecules are two α-hydroxy carboxylate organic ligands extensively used for this aim. Although some studies have shown the electrochemical synthesis of Cu/Cu2O nanolayers, no grounded discussion about the influence of the chemical nature of the ligands on the oscillatory reaction has been investigated so far. Here, we provide a well-detailed and rigorous study of the effect of both ligands in the electrodeposition of Cu/Cu2O under galvanostatic control, accurately mapping differences in the oscillation period and amplitude. On the basis of recent advances on the understanding of the copper complex structures, we attributed a distorted tetrahedral structure with four monodentate lactate ligands linked to the Cu2+ central ion ([Cu(Lac)4]2–) and a distorted square-planar coordination of the tartrate’s deprotonated alkoxide groups, forming a chelate ([Cu(TartH–2)2]6–), as the species that have a buffering effect on the oscillatory mechanism and, consequently, can control the extension of the oscillation period and amplitude. In this matter, the tartrate complex should have a higher buffering capacity to prolong the period and decrease the amplitude. More importantly, we unequivocally show that a surface blocking effect due to the adsorption reactions cannot be neglected in the mechanism description. The adsorption of the tartrate anions and its complexes has, also as an outcome, period enlargement and amplitude shrinkage, as compared to that of the lactate. Hence, both mechanisms seem to operate in the adjustment of the dynamic characteristics of the oscillatory electrodeposition of Cu/Cu2O.

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Section: Resultssupporting

confidence: 49%

Section: Resultsmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of the Ligands in Cu(II) Complexes on the Oscillatory Electrodeposition of Cu/Cu₂O

et al. 2020

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“…Hervé et al [5] applied the multivariate technique on biological data. Kitaga ki et al [6] used Hotelling T-squared statistic in chemical and electrochemical oscillator issues. For more details about the applications of the Hotelling T-squared statistic, the reader may read [3,7] and [8].…”

Section: Introductionmentioning

confidence: 99%

Multivariate Analysis under Indeterminacy: An Application to Chemical Content Data

Aslam

Arif

2020

Journal of Analytical Methods in Chemistry

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The Hotelling T-squared statistic has been widely used for the testing of differences in means for the multivariate data. The existing statistic under classical statistics is applied when observations in multivariate data are determined, precise, and exact. In practice, it is not necessary that all observations in the data are determined and precise due to measurement in complex situations and under uncertainty environment. In this paper, we will introduce the Hotelling T-squared statistic under neutrosophic statistics (NS) which is the generalization of classical statistics and applied under uncertainty environment. We will discuss the application and advantage of the neutrosophic Hotelling T-squared statistic with the aid of data. From the comparison, we will conclude that the proposed statistic is more adequate and effective in uncertainty.

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Self‐Organization in Electrochemical Synthesis as a Methodology towards New Materials

et al. 2020

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Despite its potential, self‐organization as a methodology for the synthesis of materials has not been developing at the pace required for the ample scale synthesis of materials with more complex structures. As there is an environmental demand for a fast change in the energy matrix, away from fossil fuels, by using materials with more complex composition and structure, this topic has been gaining potential. As complexity can be observed in many different fields of science, from biology to physical chemistry, this Review intends to focus on recent advances of self‐organization in electrochemical systems. To provide a deeper understanding of the literature being reviewed, the fundamentals of nonlinear dynamics in electrochemistry is discussed, based on classical literature. Following this, two electrochemical processes in which self‐organization is observed will be reviewed, namely electrodeposition and electrodissolution. In the final section, self‐organization is presented as a perspective for applied systems, where self‐organization is employed for the synthesis of materials of technological importance. This Review intends to reignite the debate on how self‐organization could be used to produce more complex materials than the traditional step‐by‐step approach could achieve.

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Multivariate statistical analysis of chemical and electrochemical oscillators for an accurate frequency selection

Abstract: This study employs a multivariate statistical analysis in chemical and electrochemical oscillators to determine the precise effect of the experimental parameters.

Cited by 10 publications

References 94 publications

Influence of the Ligands in Cu(II) Complexes on the Oscillatory Electrodeposition of Cu/Cu₂O

Influence of the Ligands in Cu(II) Complexes on the Oscillatory Electrodeposition of Cu/Cu₂O

Multivariate Analysis under Indeterminacy: An Application to Chemical Content Data

Self‐Organization in Electrochemical Synthesis as a Methodology towards New Materials

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Multivariate statistical analysis of chemical and electrochemical oscillators for an accurate frequency selection

Abstract: This study employs a multivariate statistical analysis in chemical and electrochemical oscillators to determine the precise effect of the experimental parameters.

Cited by 10 publications

References 94 publications

Influence of the Ligands in Cu(II) Complexes on the Oscillatory Electrodeposition of Cu/Cu2O

Influence of the Ligands in Cu(II) Complexes on the Oscillatory Electrodeposition of Cu/Cu2O

Multivariate Analysis under Indeterminacy: An Application to Chemical Content Data

Self‐Organization in Electrochemical Synthesis as a Methodology towards New Materials

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Product

Resources

About

Influence of the Ligands in Cu(II) Complexes on the Oscillatory Electrodeposition of Cu/Cu₂O

Influence of the Ligands in Cu(II) Complexes on the Oscillatory Electrodeposition of Cu/Cu₂O