Investigations of electrode surfaces in acetonitrile solutions using surface-enhanced Raman spectroscopy

Na 0.44 MnO 2 nanowires were acid leached in nitric acid, and dehydrated by heat treatment to induce controllable defect formation as monitored by high resolution TEM studies. The charge-discharge tests using these materials as catalysts (or ''promoters'') in rechargeable lithium-oxygen batteries (in noncarbonate electrolytes) showed that a high defect concentration results in a doubling of the reversible energy storage capacity up to 11 000 mA h g À1 , and lowered overpotentials for oxygen evolution. The role of the defects/vacancies in determining oxygen reduction behavior is highlighted.

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“…8). 25 FESEM observations of the discharge product morphology (Fig. 9) also suggest the presence of lithium hydroxide.…”

Section: Resultsmentioning

confidence: 80%

The role of vacancies and defects in Na0.44MnO2 nanowire catalysts for lithium–oxygen batteries

Lee

Black

Popov

et al. 2012

Energy Environ. Sci.

170

157

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“…Bands related with the presence of residual water in the solvent and supporting electrolyte can be observed at 3629/3544 cm –1 (OH stretching) and at 1628 cm –1 (OH bending) . At 3002/2941 cm –1 the contribution from the CH stretching from TEA + and acetonitrile can be seen as also confirmed by comparison with the transmission spectra of acetonitrile and 0.1 M TEABF 4 solution shown as inset in Figure .…”

Section: Resultsmentioning

confidence: 86%

In Situ Spectroscopic Study of CO₂ Electroreduction at Copper Electrodes in Acetonitrile

2016

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The electrochemical conversion of carbon dioxide (CO 2 ) into valuable compounds is a promising route toward the valorization of this molecule of high environmental impact. Yet, an industrial process involving CO 2 electroreduction is still far from reality and requires deep and fundamental studies for a further understanding and better development of the process. In this work, we describe in situ spectroelectrochemical studies based on Fourier transform infrared spectroscopy and surface-enhanced Raman spectroscopy of the CO 2 reduction in acetonitrile solutions at copper electrodes. The influence of factors such as the water content and the supporting electrolyte on the reaction products were evaluated and compared to products obtained on metal electrodes other than Cu, such as Pt, Pb, Au, Pd, and Ag. The results show that at Cu electrodes in acetonitrile containing small amounts of water, the main reaction products from CO 2 reduction are carbonate, bicarbonate, and CO. The formation of CO was observed at less-negative potentials than the formation of (bi)carbonates, and the formation of carbonate and bicarbonate species appears to be the result of a reaction with electrochemically generated OH − from water reduction. In general, our experiments show the sensitivity of the CO 2 reduction reaction to the presence of water, even at the residual level.

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“…The characteristic band observed at 2254 cm -1 at all potentials that were investigated (Figure , similar band features were omitted at potentials other than −0.4 V for clear presentation) corresponds to the CN triple-bond stretch of bulk solvent acetonitrile. However, the SERS spectra of acetonitrile has been observed on a roughened silver electrode by Irish and co-workers . With the onset of the decomposition, the decrease in the CN-band intensity of acetonitrile can be clearly observed in their studies.…”

Section: Resultsmentioning

confidence: 99%

On the Occurrence of Competitive Adsorption at the Platinum−Acetonitrile Interface by Using Surface-Enhanced Raman Spectroscopy

Cao

Sun

Gu³

2003

J. Phys. Chem. B

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Surface-enhanced Raman scattering (SERS) from the platinum electrode−acetonitrile interface in the presence of iodide, the lithium cation, water, and pyridine was analyzed as a function of applied potential. It was found that the typical Raman band of cyanide species by the dissociation of the solvent acetonitrile upon adsorption onto highly roughened platinum electrode surfaces was detectable for all of the systems that were studied. However, the onset potential of the dissociation reaction of acetontrile differed for the four systems. We assume that competitive adsorption may exist between each of the above four species and the solvent acetonitrile molecule, especially at the dissociation reaction−active sites of the Pt surface. This competitive adsorption therefore significantly inhibits the decomposition reaction of acetonitrile. The interactions of these adsorbates with Pt are assumed to weaken in the sequence pyridine > I- > water ≈ Li+ on the basis of the observations of different negative shifts of the onset potential of acetonitrile decomposition. For the system with water or iodide, double-band character for the CN band was also detected. It is assumed to be due to the existence of two types of adsorbed ion pairs at the Pt surface: CN-···CH3CN and CN-···Li+/Na+.

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Investigations of electrode surfaces in acetonitrile solutions using surface-enhanced Raman spectroscopy

Cited by 37 publications

References 50 publications

The role of vacancies and defects in Na0.44MnO2 nanowire catalysts for lithium–oxygen batteries

The role of vacancies and defects in Na0.44MnO2 nanowire catalysts for lithium–oxygen batteries

In Situ Spectroscopic Study of CO₂ Electroreduction at Copper Electrodes in Acetonitrile

On the Occurrence of Competitive Adsorption at the Platinum−Acetonitrile Interface by Using Surface-Enhanced Raman Spectroscopy

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Investigations of electrode surfaces in acetonitrile solutions using surface-enhanced Raman spectroscopy

Cited by 37 publications

References 50 publications

The role of vacancies and defects in Na0.44MnO2 nanowire catalysts for lithium–oxygen batteries

The role of vacancies and defects in Na0.44MnO2 nanowire catalysts for lithium–oxygen batteries

In Situ Spectroscopic Study of CO2 Electroreduction at Copper Electrodes in Acetonitrile

On the Occurrence of Competitive Adsorption at the Platinum−Acetonitrile Interface by Using Surface-Enhanced Raman Spectroscopy

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In Situ Spectroscopic Study of CO₂ Electroreduction at Copper Electrodes in Acetonitrile