Electrocatalytic behaviour of surface confined pentanethio cobalt (II) binuclear phthalocyanines towards the oxidation of 4-chlorophenol

Makinde, Zainab O.; Louzada, Marcel; Mashazi, Philani; Nyokong, Tebello; Khene, Samson

doi:10.1016/j.apsusc.2017.06.271

Cited by 17 publications

(11 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The adsorption step was monitored by the in situ quartz crystal microbalance (QCM) technique (Figure S8, Supporting Information), which indicated surface coverage values in the order of 10 –11 mol/cm 2 (inset of Figure S8, Supporting Information). This confirms that the electrodes were modified by a monolayer of molecular electrocatalysts with a flat orientation on the surface. , When these modified electrodes were used for the above-mentioned electrooxidation reactions, a similar trend with respect to the overpotential was observed (Figure S9, Supporting Information) as that in Figure , which confirms that this behavior is intrinsic to the molecules. We also carried out chronopotentiometric analysis for the water oxidation reaction for nearly 8 h along with postelectrochemical characterization of the electrodes in order to prove the chemical stability and integrity of molecular electrocatalysts (Figures S10 and S11, Supporting Information).…”

mentioning

confidence: 99%

Unprecedented Isomerism–Activity Relation in Molecular Electrocatalysis

Kottaichamy

Begum

Nazrulla

et al. 2019

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

The role of electrocatalysts in energy storage/conversion, biomedical and environmental sectors, green chemistry, and much more has generated enormous interest in comprehending their structure–activity relations. While targeting the surface-to-volume ratio, exposing reactive crystal planes and interfacial modifications are time-tested considerations for activating metallic catalysts; it is primarily by substitution in molecular electrocatalysts. This account draws the distinction between a substituent’s chemical identity and isomerism, when regioisomerism of the −NO2 substituent is conferred at the “α” and “β” positions on the macrocycle of cobalt phthalocyanines. Spectroscopic analysis and theoretical calculations establish that the β isomer accumulates catalytically active intermediates via a cumulative influence of inductive and resonance effects. However, the field effect in the α isomer restricts this activation due to a vanishing resonance effect. The demonstration of the distinct role of isomerism in substituted molecular electrocatalysts for reactions ranging from energy conversion to biosensing highlights that isomerism of the substituents makes an independent contribution to electrocatalysis over its chemical identity.

show abstract

mentioning

confidence: 99%

Unprecedented Isomerism–Activity Relation in Molecular Electrocatalysis

Kottaichamy

Begum

Nazrulla

et al. 2019

J. Phys. Chem. Lett.

View full text Add to dashboard Cite

show abstract

“…The surface coverage values obtained from QCM were in the order of 10 –11 mol/cm 2 (Table S4, Supporting Information). As per the literature, this surface coverage value reflects a monolayer of molecular electrocatalysts on the electrode with nearly a flat orientation. , Their electrochemical behavior with respect to the isomerism of −NO 2 functionality toward arsenic(III) oxidation (Figure S9, Supporting Information) confirm that the activity of the isomeric molecules are their inherent property and isomerism of substituents contributes independently over their nature in electrocatalysis.…”

Section: Resultsmentioning

confidence: 99%

Geometrical Isomerism Directed Electrochemical Sensing

et al. 2020

View full text Add to dashboard Cite

We report the independent role of isomerism of secondary sphere substituents over their nature, a factor often overlooked in molecular electrocatalysis pertaining to electrochemical sensing, by establishing that isomerism redefines the electronic structure at the catalytic reaction center via geometrical factors. UV–vis spectroscopy and X-ray photoelectron spectroscopy suggest that a substituent’s isomerism in molecular catalysts conjoins molecular planarity and catalytic activation through competing field effects and resonance effects. As a classical example, we demonstrate the influence of isomerism of the −NO2 substituents for the electrocatalytic multi electron oxidation of As(III), a potentially important electrochemical pathway for water remediation and arsenic detection. The isomerism dependent oxidative activation of catalytic center leads to a nonprecious molecular catalyst capable for direct As(III) oxidation with an experimental detection limit close to WHO guidelines. This work opens up an unusual approach in analytical chemistry for developing various sensing platforms for challenging chemical and electrochemical reactions.

show abstract

“…Because of their high conductivity and excellent chemical inertness against environmental corrosion, noble metals like platinum (Pt) 12,49 and gold (Au) 36,38 are widely used as working electrodes in electrochemical CP sensing systems. The high density of electronic states and the number of atomic orbitals within the noble metals enable not only free electron migration in the bulk phase, but also fast heterogeneous electron transfer on the surface, [96][97][98] which is conducive to facilitating the redox reactions of CPs.…”

Section: Electrochemical Cell Configurationmentioning

confidence: 99%

“…4a, there are mainly two strategies to overcome sluggish kinetics and fouling effect, one is to adjust the electrode surface itself (e.g., electrochemical dealloying), 98 and another is to modify the surface with active materials (e.g., phthalocyanines). 36,96 For the former, Quynh and coworkers 98 have developed a nanoporous electrode through electrochemical dealloying of silicon (Si) out of Au-Si or Pt-Si alloy thin films. With the 3D porous network of interconnected noble-metal ligaments on the order of nanometers (Fig.…”

Section: Electrochemical Cell Configurationmentioning

confidence: 99%

“…72 Due to the relatively low cost and wide availability of carbon materials, carbon-based electrodes have been widely used ever since graphite electrodes were introduced for electrochemical production of alkali metals. [94][95][96][97][98][99] Diverse carbon-based electrodes emerge, benefiting from the presence of abundant allotropes of carbon including the sp 2 hybridized graphitic carbon materials (graphite, glassy carbon, carbon black, etc. ), and the completely sp 3 hybridized tetrahedral diamond.…”

Section: Electrochemical Cell Configurationmentioning

confidence: 99%

See 1 more Smart Citation