Topic
Partial current
About: Partial current is a research topic. Over the lifetime, 217 publications have been published within this topic receiving 4423 citations.
Papers published on a yearly basis
Papers
TL;DR: The electrochemical model reported here is simple, fairly easy to implement, and involves only a small increase in computational cost over calculations neglecting the effects of the electrolyte and the applied field, Therefore, it can be used to study theeffects of applied potential and electrolyte composition on the energetics of surface reactions for a wide variety of electrochemical reactions.
Abstract: We have carried out a periodic Kohn-Sham density functional theory investigation of the pathways by which carbon-carbon bonds could be formed during the electrochemical reduction of CO2 on Cu(100) using a model that includes the effects of the electrochemical potential, solvent, and electrolyte. The electrochemical potential was set by relating the applied potential to the Fermi energy and then calculating the number of electrons required by the simulation cell for that specific Fermi energy. The solvent was included as a continuum dielectric, and the electrolyte was described using a linearized Poisson-Boltzmann model. The calculated potential of zero charge for a variety of surfaces agrees with experiment to within a mean average error of 0.09 V, thereby validating the assumptions of the model. Analysis of the mechanism for C-C bond formation revealed that at low-applied potential, C-C bond formation occurs through a CO dimer. However, at high applied potentials, a large activation barrier blocks this pathway; therefore, C-C bond formation occurs through reaction of adsorbed CHO and CO. Rate parameters determined from our calculations were used to simulate the kinetics of ethene formation during the electrochemical reduction of CO over a Cu(100) surface. An excellent match was observed between previously reported measurements of the partial current for ethene formation as a function of applied voltage and the variation in the partial current for C-C bond formation predicted by our microkinetic model. The electrochemical model reported here is simple, fairly easy to implement, and involves only a small increase in computational cost over calculations neglecting the effects of the electrolyte and the applied field. Therefore, it can be used to study the effects of applied potential and electrolyte composition on the energetics of surface reactions for a wide variety of electrochemical reactions.
584 citations
TL;DR: In this article, the influence of electrolyte composition on the electrochemical reduction of CO2 to CO in an electrochemical flow reactor was investigated, and the effect of alkali cations on the partial current densities of the two products: CO and H2.
Abstract: We investigate the influence of electrolyte composition on the electrochemical reduction of CO2 to CO in an electrochemical flow reactor. Specifically, we study the effect of alkali cations on the partial current densities of the two products: CO and H2 .W e report that the presence of large cations such as cesium and rubidium in the electrolyte improves the partial current density for CO production. Furthermore, large cations suppress H2 evolution, resulting in high faradaic yields for CO production. For example, with a large cation, specifically CsOH, a partial current density of 72 mA/cm 2 was obtained at a cathode potential of −1.62 V vs Ag/AgCl. In contrast, in the presence of a small cation, specifically sodium, a partial current density of only 49 mA/cm 2 was achieved at a much more negative cathode potential of −2.37 V vs Ag/AgCl, with NaBr. The effect of cation size on product selectivity for CO production can be explained by the interplay between the level of cation hydration and the extent of cation adsorption on Ag electrodes.
332 citations
TL;DR: In this article, structural effects on the rates of CO 2 reduction were studied on Ag(111), Ag(100) electrodes in 0.1 M KHCO 3 using macroelectrolysis.
277 citations
TL;DR: In this paper, CO2 is reduced to CO in 0.5 M aqueous KHCO3 solution at a gold electrode at 18°C, the reaction proceeding with markedly low overvoltage, starting at −0.8 V vs. normal hydrogen electrode (N.H.E).
Abstract: CO2 is electrochemically reduced to CO in 0.5 M aqueous KHCO3 solution at a gold electrode at 18°C, the reaction proceeding with markedly low overvoltage, starting at –0.8 V vs. normal hydrogen electrode (N.H.E.); the faradaic efficiency for CO formation is 91% at –1.10 V vs. N.H.E. with a partial current of 3.7 mA cm–2, and the reaction probably proceeds via adsorbed intermediates.
261 citations
TL;DR: The results of this work highlight the importance of carrying out a carbon balance, in addition to traditional measurements of activity and selectivity, to adequately assess the performance of CO2 reduction devices at high current densities, and inform future efforts aimed at mitigating membrane crossover in MEA-type electrolyzers forCO2 reduction.
Abstract: Cell designs that integrate membrane-electrode assemblies (MEAs) with highly selective catalysts are a promising route to reduce ohmic losses and achieve high energy efficiency in CO2 reduction at industrially relevant current densities. In this work, porous silver filtration membranes are demonstrated as simple and efficient gas-diffusion electrodes for CO2 reduction to CO at high current densities in an MEA-type device. A partial current density for CO of up to ca. 200 mA cm-2 was achieved at a cell voltage of ca. 3.3 V, in tandem with minimal H2 production. However, the analysis of cathodic and anodic outlet streams revealed that CO2 cross-over across the anion-exchange membranes, mostly in the form of CO32- but partially as HCOO- generated over the cathode, actually exceeds the amount of CO2 converted to the target product, resulting in a poor utilization of the reactant and in the early onset of mass transfer limitations. In addition, CO2 cross-over leads to a nonstoichiometric decrease of the outlet flow rate from the cathodic compartment. This effect can lead to a substantial overestimation of catalytic performance if the inlet flow rate of CO2 is used as reference for calculating partial current densities and Faradaic efficiencies. The results of this work highlight the importance of carrying out a carbon balance, in addition to traditional measurements of activity and selectivity, to adequately assess the performance of CO2 reduction devices at high current densities, and inform future efforts aimed at mitigating membrane cross-over in MEA-type electrolyzers for CO2 reduction.
232 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 13 |
| 2020 | 9 |
| 2019 | 9 |
| 2018 | 3 |
| 2017 | 3 |
| 2016 | 3 |