ATR-SEIRAS for time-resolved studies of electrode–electrolyte interfaces

Cuesta, Ángel

doi:10.1016/j.coelec.2022.101041

Cited by 24 publications

(17 citation statements)

References 36 publications

(37 reference statements)

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“…For instance, peaks with positive absorbances indicate increases in the interfacial concentration of the grafting species and/or species with conformations favorable for observation according to SEIRAS selection rules, while peaks with negative absorbance correlate to the opposite. 44 Interpretation of ATR data is based on previously reported IR assignments for graphene, graphene oxide, and 4-amino-TEMPO (Table S1). 27,28,45−48 Figure 2a shows the time-resolved spectra acquired while maintaining a 1.1 V potential for 10 min in a 1 mM 4-amino-TEMPO PBS solution.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Using such a background distinguishes changes in IR bands that correspond to modification of the substrate during the grafting process. For instance, peaks with positive absorbances indicate increases in the interfacial concentration of the grafting species and/or species with conformations favorable for observation according to SEIRAS selection rules, while peaks with negative absorbance correlate to the opposite . Interpretation of ATR data is based on previously reported IR assignments for graphene, graphene oxide, and 4-amino-TEMPO (Table S1).…”

Section: Resultsmentioning

confidence: 99%

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Monitoring SEIRAS on a Graphitic Electrode for Surface-Sensitive Electrochemistry: Real-Time Electrografting

Siddiqui,

N’Diaye,

Martin

et al. 2024

Anal. Chem.

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The ubiquity of graphitic materials in electrochemistry makes it highly desirable to probe their interfacial behavior under electrochemical control. Probing the dynamics of molecules at the electrode/electrolyte interface is possible through spectroelectrochemical approaches involving surface-enhanced infrared absorption spectroscopy (SEIRAS). Usually, this technique can only be done on plasmonic metals such as gold or carbon nanoribbons, but a more convenient substrate for carbon electrochemical studies is needed. Here, we expanded the scope of SEIRAS by introducing a robust hybrid graphene-on-gold substrate, where we monitored electrografting processes occurring at the graphene/ electrolyte interface. These electrodes consist of graphene deposited onto a roughened gold-sputtered internal reflection element (IRE) for attenuated total reflectance (ATR) SEIRAS. The capabilities of the graphene-gold IRE were demonstrated by successfully monitoring the electrografting of 4-amino-2,2,6,6-tetramethyl-1-piperidine Noxyl (4-amino-TEMPO) and 4-nitrobenzene diazonium (4-NBD) in real time. These grafts were characterized using cyclic voltammetry and ATR-SEIRAS, clearly showing the 1520 and 1350 cm −1 NO 2 stretches for 4-NBD and the 1240 cm −1 C−C, C− C−H, and N−O ̇stretch for 4-amino-TEMPO. Successful grafts on graphene did not show the SEIRAS effect, while grafting on gold was not stable for TEMPO and had poorer resolution than on graphene-gold for 4-NBD, highlighting the uniqueness of our approach. The graphene-gold IRE is proficient at resolving the spectral responses of redox transformations, unambiguously demonstrating the real-time detection of surface processes on a graphitic electrode. This work provides ample future directions for real-time spectroelectrochemical investigations of carbon electrodes used for sensing, energy storage, electrocatalysis, and environmental applications.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Monitoring SEIRAS on a Graphitic Electrode for Surface-Sensitive Electrochemistry: Real-Time Electrografting

Siddiqui,

N’Diaye,

Martin

et al. 2024

Anal. Chem.

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“…Nevertheless, a new band at 1635 cm –1 (marked with * in Figure g) appears in both the IM + EE and IM + EC cathode spectra. This band is very likely attributed to the H–O–H bending mode of water molecules trapped in the imidazolium ad-layer next to the electrode. ,, Moreover, this low-wavelength band is related to the OH-stretching band at 3610 cm –1 , which is consistent with previous studies (Figure S12). Finally, the IM + EC cathode spectrum presents three additional bands: the first one at 1054 cm –1 attributed to the secondary aliphatic amines stretching mode (C–N stretching or C–N elongation vibration); the other two bands are at 840 and 746 cm –1 , associated with C–Cl and C–Br elongation vibration modes, respectively, and due to an incomplete imidazolium functionalization of the electrode.…”

Section: Resultsmentioning

confidence: 99%

Smart Electrode Surfaces by Electrolyte Immobilization for Electrocatalytic CO₂ Conversion

Vichou,

Adjez,

et al. 2024

J. Am. Chem. Soc.

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The activity and selectivity of molecular catalysts for the electrochemical CO 2 reduction reaction (CO 2 RR) are influenced by the induced electric field at the electrode/electrolyte interface. We present here a novel electrolyte immobilization method to control the electric field at this interface by positively charging the electrode surface with an imidazolium cation organic layer, which significantly favors CO 2 conversion to formate, suppresses hydrogen evolution reaction, and diminishes the operating cell voltage. Those results are well supported by our previous DFT calculations studying the mechanistic role of imidazolium cations in solution for CO 2 reduction to formate catalyzed by a model molecular catalyst. This smart electrode surface concept based on covalent grafting of imidazolium on a carbon electrode is successfully scaled up for operating at industrially relevant conditions (100 mA cm −2 ) on an imidazolium-modified carbon-based gas diffusion electrode using a flow cell configuration, where the CO 2 conversion to formate process takes place in acidic aqueous solution to avoid carbonate formation and is catalyzed by a model molecular Rh complex in solution. The formate production rate reaches a maximum of 4.6 g HCOO − m −2 min −1 after accumulating a total of 9000 C of charge circulated on the same electrode. Constant formate production and no significant microscopic changes on the imidazolium-modified cathode in consecutive long-term CO 2 electrolysis confirmed the high stability of the imidazolium organic layer under operating conditions for CO 2 RR.

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“…But the bulk and interfacial electrolyte structures can show stark contrast; hence, understanding and comprehending the interfacial electrolyte structure as a function of potential can give us a clear picture of the effect of DMF on modifying the electrochemical interface at potentials relevant for the CO2RR. The interfacial structure of the electrolyte was probed by in situ ATR-SEIRAS (Figure ) to gain insights about the potential-induced accumulation/depletion and reorientation of water and DMF, as well as the adsorption and desorption of intermediates and spectators. ,− …”

Section: Resultsmentioning

confidence: 99%

“…Since the CO2RR (indeed, all electrochemical reactions) is an interfacial process, a deep understanding of the electrode–electrolyte interface is crucial. Infrared spectroscopy has become an indispensable tool in electrochemistry, particularly in electrocatalysis, since it allows in situ , nondestructive, and label-free analysis of species at the electrode–electrolyte interface . We conducted in situ studies of the electrochemical interface under investigation using surface-enhanced infrared spectroscopy in the attenuated total reflection mode (ATR-SEIRAS).…”

Section: Introductionmentioning

confidence: 99%

Tailoring the Interfacial Water Structure by Electrolyte Engineering for Selective Electrocatalytic Reduction of Carbon Dioxide

2023

Self Cite

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Engineering aqueous electrolytes with low amounts of additives to achieve a tunable CO2 reduction product is an underexplored territory in electrocatalysis. Here, we show the enhancement of the Faradaic efficiency (FE) of CO2 reduction to CO on unmodified polycrystalline gold from ∼67 to ∼94% by the addition of up to 15 mol % of N,N-dimethylformamide (DMF) to an aqueous electrolyte. The role of electrolyte structure modification near the electrode–electrolyte interface was studied using in situ surface-enhanced infrared absorption spectroscopy in attenuated total reflection mode (ATR-SEIRAS). In addition to the expected detection of the adsorbed CO (COad) intermediate present on the Au surface, in both the linearly bonded and bridge-bonded forms, we observed changes in the structure of interfacial water induced by the addition of DMF. The changes in the water stretching band and the DMF carbonyl band indicate an increase in the strongly hydrogen-bonded DMF–water pairs with increasingly negative potential near the interface in the presence of DMF. We hold this interfacial water structure modification by DMF responsible for increasing the CO2RR FE and decreasing the competing hydrogen evolution reaction (HER). Furthermore, the suppression of the HER is observed in other electrolytes and also when platinum was used as an electrode and hence can be a potential method for increasing the product selectivity of complex electrocatalytic reactions.

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ATR-SEIRAS for time-resolved studies of electrode–electrolyte interfaces

Cited by 24 publications

References 36 publications

Monitoring SEIRAS on a Graphitic Electrode for Surface-Sensitive Electrochemistry: Real-Time Electrografting

Monitoring SEIRAS on a Graphitic Electrode for Surface-Sensitive Electrochemistry: Real-Time Electrografting

Smart Electrode Surfaces by Electrolyte Immobilization for Electrocatalytic CO₂ Conversion

Tailoring the Interfacial Water Structure by Electrolyte Engineering for Selective Electrocatalytic Reduction of Carbon Dioxide

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ATR-SEIRAS for time-resolved studies of electrode–electrolyte interfaces

Cited by 24 publications

References 36 publications

Monitoring SEIRAS on a Graphitic Electrode for Surface-Sensitive Electrochemistry: Real-Time Electrografting

Monitoring SEIRAS on a Graphitic Electrode for Surface-Sensitive Electrochemistry: Real-Time Electrografting

Smart Electrode Surfaces by Electrolyte Immobilization for Electrocatalytic CO2 Conversion

Tailoring the Interfacial Water Structure by Electrolyte Engineering for Selective Electrocatalytic Reduction of Carbon Dioxide

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Smart Electrode Surfaces by Electrolyte Immobilization for Electrocatalytic CO₂ Conversion