Measurements of the double layer capacitance for electrodes in supercritical CO2/acetonitrile electrolytes

Bartlett, Philip N.; Cook, David

doi:10.1016/j.jelechem.2015.03.022

Cited by 7 publications

(7 citation statements)

References 43 publications

(49 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These double-layer capacitances, calculated without explicit water molecules, were calculated as 18 and 22 μF/cm 2 for Au(111) and Pt(111), respectively (for further details, see the Supporting Information). This is in reasonable agreement with the experimental values that show a wide range between 10 and 40 μF/cm 2 for Au(111) − and between 9 and 38 μF/cm 2 − for Pt(111) and the computational result based on the application of JDFT, , where a value of 19 μF/cm 2 for Pt(111) has been reported. It should be emphasized, however, that the double-layer capacitance is highly dependent on the electrolyte in the experimental setup, where the value can differ by a factor of 2 …”

Section: Resultssupporting

confidence: 91%

Controlled-Potential Simulation of Elementary Electrochemical Reactions: Proton Discharge on Metal Surfaces

2018

View full text Add to dashboard Cite

The simulation of electrochemical reaction dynamics from first principles remains challenging, since over the course of an elementary step, an electron is either consumed or produced by the electrode. For example, the hydrogen evolution reaction begins with a simple proton discharge to a metal surface, but with conventional electronic structure methods, the simulated potential, which is manifested as the metal’s workfunction, varies over the course of the simulation as the electron is consumed in the new metal–hydrogen bond. Here, we present a simple approach to allow the direct control of the electrochemical potential via charging of the electrode surface. This is achieved by changing the total number of electrons in the self-consistent cycle, while enforcing charge neutrality through the introduction of a jellium counter charge dispersed in an implicit solvent region above the slab. We observe that the excess electrons localize selectively at the metal’s reactive surface and that the metal workfunction responds nearly linearly to the variation in electronic count. This linear response allows for control of the potential in simulations with a minimal computational penalty compared to standard electronic structure calculations. This scheme can be straightforwardly implemented with common electronic structure calculators (density functional theory in the present work), and we find this method to be compatible with the commonly used computational hydrogen electrode model, which we expect will make it useful in the construction of potential-dependent free-energy diagrams in electrochemistry. We apply this approach to the proton-deposition (Volmer) step on both Au(111) and Pt(111) surfaces and show that we can reliably control the simulated electrode potential and thus assess the potential dependence of the initial, transition, and final states. Our method allows us to directly assess the location along the reaction pathway with the greatest amount of charge transfer, which we find to correspond well with the reaction barrier, indicating this reaction is a concerted proton–electron transfer. Interestingly, we show that the Pt electrode has not only a more favorable equilibrium energy with adsorbed hydrogen but also a lower intrinsic barrier under thermoneutral conditions.

show abstract

Section: Resultssupporting

confidence: 91%

Controlled-Potential Simulation of Elementary Electrochemical Reactions: Proton Discharge on Metal Surfaces

2018

View full text Add to dashboard Cite

show abstract

“…Recently, Bartlett & Cook [ 61 ] published results for the study of the double-layer capacitance in scCO 2 /11 wt% MeCN mixtures of constant density between 306 K, 15.5 MPa and 316 K, 20.2 MPa. They found that the results for Pt and Au electrodes could be described by a simple Helmholtz layer model.…”

Section: Supercritical Fluids As Solvents For Electrochemistrymentioning

confidence: 99%

“…Black squares: 0.5 mm diameter platinum disc; red circles: 0.5 mm diameter gold disc; blue triangles: 1 mm diameter glassy carbon disc [61]. (Reproduced with permission from [61]. Copyright c Elsevier.…”

Section: (C) the Double Layer In Supercritical Fluidsmentioning

confidence: 99%

“…Comparison of C dl for different substrates in scCO 2 /11 wt% CH 3 CN with 12.15 mM [NBu n 4 ][BF 4 ] at 306 K and 15.5 MPa.Open symbols represent data taken on the cathodic scan; filled symbols on the anodic scan. Black squares: 0.5 mm diameter platinum disc; red circles: 0.5 mm diameter gold disc; blue triangles: 1 mm diameter glassy carbon disc[61]. (Reproduced with permission from[61].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Electrochemistry in supercritical fluids

Branch¹,

Bartlett²

2015

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

A wide range of supercritical fluids (SCFs) have been studied as solvents for electrochemistry with carbon dioxide and hydrofluorocarbons (HFCs) being the most extensively studied. Recent advances have shown that it is possible to get well-resolved voltammetry in SCFs by suitable choice of the conditions and the electrolyte. In this review, we discuss the voltammetry obtained in these systems, studies of the double-layer capacitance, work on the electrodeposition of metals into high aspect ratio nanopores and the use of metallocenes as redox probes and standards in both supercritical carbon dioxide–acetonitrile and supercritical HFCs.

show abstract

“…Numerous reports exist concerning the solubility of inorganic salts and small organic molecules in scCO 2 , − the conductivity of scCO 2 and applicable electrolyte additives, ,,− voltammetric experiments on ferrocene and decamethylferrocene, , and electrochemical metal depositions in scCO 2 . − Nevertheless, only a few reports have so far addressed the electrochemical reduction of scCO 2 itself under such conditions. , Thus, a deeper understanding of the performance gain using scCO 2 for the CO 2 R is yet to be established.…”

Section: Introductionmentioning

confidence: 99%

Assessing the Influence of Supercritical Carbon Dioxide on the Electrochemical Reduction to Formic Acid Using Carbon-Supported Copper Catalysts

et al. 2020

View full text Add to dashboard Cite

The electrocatalytic reduction of carbon dioxide (CO2) by means of renewable energies is widely recognized as a promising approach to establish a sustainable closed carbon cycle economy. However, widespread application is hampered by the inherent difficulty in suppressing the hydrogen evolution reaction and controlling the overall process selectivity. Further critical parameters are the limited solubility of CO2 in many electrolytes and its hindered mass transport to the electrodes. Herein we report on a series of nanoparticle Cu electrocatalysts on different carbon supports and their potential to perform the electrochemical CO2 reduction under supercritical conditions (scCO2). Herein, CO2 serves as the reaction medium and reactant alike. By a detailed comparison to ambient conditions we show that scCO2 conditions largely suppress the undesirable hydrogen evolution and favor the production of formic acid by the Cu electrodes. Furthermore, we show that scCO2 conditions significantly prevent Cu nanoparticle agglomeration during electrocatalysis.

show abstract

Measurements of the double layer capacitance for electrodes in supercritical CO2/acetonitrile electrolytes

Cited by 7 publications

References 43 publications

Controlled-Potential Simulation of Elementary Electrochemical Reactions: Proton Discharge on Metal Surfaces

Controlled-Potential Simulation of Elementary Electrochemical Reactions: Proton Discharge on Metal Surfaces

Electrochemistry in supercritical fluids

Assessing the Influence of Supercritical Carbon Dioxide on the Electrochemical Reduction to Formic Acid Using Carbon-Supported Copper Catalysts

Contact Info

Product

Resources

About