scholarly journals Electrochemical Reduction of CO2 to CO on Hydrophobic Zn Foam Rod in a Microchannel Electrochemical Reactor

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1592
Author(s):  
Chunxiao Zhang ◽  
Shenglin Yan ◽  
Jing Lin ◽  
Qing Hu ◽  
Juhua Zhong ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Saturated Calomel Electrode ◽  
Co2 Reduction ◽  
Active Surface ◽  
Active Surface Area ◽  
Mass Transfer Limitation ◽  
Faradaic Efficiency ◽  
Electrochemical Co2 Reduction ◽  
Hydrophobic Layer ◽  
Co2 Mass Transfer

Due to CO2 mass transfer limitation as well as the competition of hydrogen evolution reaction in electroreduction of CO2 in the aqueous electrolyte, Zn-based electrodes normally exhibit unsatisfying selectivity for CO production, especially at high potentials. In this work, we introduced a zinc myristate (Zn [CH3(CH2)12COO]2) hydrophobic layer on the surface of zinc foam electrode by an electrodeposition method. The obtained hydrophobic zinc foam electrode showed a high Faradaic efficiency (FE) of 91.8% for CO at −1.9 V (vs. saturated calomel electrode, SCE), which was a remarkable improvement over zinc foam (FECO = 81.87%) at the same potentials. The high roughness of the hydrophobic layer has greatly increased the active surface area and CO2 mass transfer performance by providing abundant gas-liquid-solid contacting area. This work shows adding a hydrophobic layer on the surface of the catalyst is an effective way to improve the electrochemical CO2 reduction performance.

scholarly journals Electrochemical CO2 Reduction on Nanostructured Metal Electrodes: Fact or Defect?

2019 ◽  
Author(s):  
Recep Kas ◽  
Kailun Yang ◽  
Divya Bohra ◽  
Ruud Kortlever ◽  
Thomas Burdyny ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Structural Changes ◽  
Co2 Reduction ◽  
Catalyst Layer ◽  
Active Surface ◽  
Process Conditions ◽  
Active Surface Area ◽  
Catalytic Layer ◽  
Nanostructured Electrodes ◽  
Electrochemical Co2 Reduction

<div> <p>Electrochemical CO<sub>2</sub> reduction has received an increased amount of interest in the last decade as a promising avenue for storing renewable electricity in chemical bonds. Despite considerable progress on catalyst performance using nanostructured electrodes, the sensitivity of the reaction to process conditions has led to debate on the origin of the activity and high selectivity. Additionally, this raises questions on the transferability of the performance and knowledge to other electrochemical systems. At its core, the discrepancy is primarily a result of the highly porous nature of nanostructured electrodes, which are vulnerable to both mass transport effects and structural changes during the electrolysis. Both effects are not straightforward to identify and difficult to decouple. Despite the susceptibility of nanostructured electrodes to mass transfer limitations, we highlight that nanostructured silver electrodes exhibit considerably higher activity when normalized to the electrochemically active surface in contrast to gold and copper electrodes. Alongside, we provide a discussion on how active surface area and thickness of the catalytic layer itself can influence the selectivity, stability, activity and mass transfer inside and outside of the three dimensional catalyst layer. Key parameters and potential solutions are highlighted to decouple mass transfer effects from the measured activity in electrochemical cells utilizing CO<sub>2</sub> saturated aqueous solutions. </p> </div> <br>

scholarly journals Electrochemical CO2 Reduction on Nanostructured Metal Electrodes: Fact or Defect?

2019 ◽  
Author(s):  
Recep Kas ◽  
Kailun Yang ◽  
Divya Bohra ◽  
Ruud Kortlever ◽  
Thomas Burdyny ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Structural Changes ◽  
Co2 Reduction ◽  
Catalyst Layer ◽  
Active Surface ◽  
Process Conditions ◽  
Active Surface Area ◽  
Catalytic Layer ◽  
Nanostructured Electrodes ◽  
Electrochemical Co2 Reduction

<div> <p>Electrochemical CO<sub>2</sub> reduction has received an increased amount of interest in the last decade as a promising avenue for storing renewable electricity in chemical bonds. Despite considerable progress on catalyst performance using nanostructured electrodes, the sensitivity of the reaction to process conditions has led to debate on the origin of the activity and high selectivity. Additionally, this raises questions on the transferability of the performance and knowledge to other electrochemical systems. At its core, the discrepancy is primarily a result of the highly porous nature of nanostructured electrodes, which are vulnerable to both mass transport effects and structural changes during the electrolysis. Both effects are not straightforward to identify and difficult to decouple. Despite the susceptibility of nanostructured electrodes to mass transfer limitations, we highlight that nanostructured silver electrodes exhibit considerably higher activity when normalized to the electrochemically active surface in contrast to gold and copper electrodes. Alongside, we provide a discussion on how active surface area and thickness of the catalytic layer itself can influence the selectivity, stability, activity and mass transfer inside and outside of the three dimensional catalyst layer. Key parameters and potential solutions are highlighted to decouple mass transfer effects from the measured activity in electrochemical cells utilizing CO<sub>2</sub> saturated aqueous solutions. </p> </div> <br>

Effect of mass transfer and kinetics in ordered Cu-mesostructures for electrochemical CO2 reduction

2018 ◽  
Vol 232 ◽  
pp. 391-396 ◽  
Author(s):  
Hakhyeon Song ◽  
Mintaek Im ◽  
Jun Tae Song ◽  
Jung-Ae Lim ◽  
Beom-Sik Kim ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Co2 Reduction ◽  
Electrochemical Co2 Reduction

Electrochemical CO2 reduction to methane with remarkably high Faradaic efficiency in the presence of a proton permeable membrane

2020 ◽  
Vol 13 (10) ◽  
pp. 3567-3578 ◽  
Author(s):  
Hanqing Pan ◽  
Christopher J. Barile
Keyword(s):  
Co2 Reduction ◽  
Permeable Membrane ◽  
Faradaic Efficiency ◽  
Electrochemical Co2 Reduction

Cu electrodes modified with a Nafion layer catalyze the reduction of CO2 to CH4 with up to 88% Faradaic efficiency.

scholarly journals Zn- and Ti-Doped SnO2 for Enhanced Electroreduction of Carbon Dioxide

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2354
Author(s):  
Katarzyna Bejtka ◽  
Nicolò B. D. Monti ◽  
Adriano Sacco ◽  
Micaela Castellino ◽  
Samuele Porro ◽  
...  
Keyword(s):  
Formic Acid ◽  
Current Density ◽  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Active Surface ◽  
Active Surface Area ◽  
Co2 Conversion ◽  
Hydrogen Electrode ◽  
Faradaic Efficiency ◽  
Wet Impregnation

The electrocatalytic reduction of CO2 into useful fuels, exploiting rationally designed, inexpensive, active, and selective catalysts, produced through easy, quick, and scalable routes, represents a promising approach to face today’s climate challenges and energy crisis. This work presents a facile strategy for the preparation of doped SnO2 as an efficient electrocatalyst for the CO2 reduction reaction to formic acid and carbon monoxide. Zn or Ti doping was introduced into a mesoporous SnO2 matrix via wet impregnation and atomic layer deposition. It was found that doping of SnO2 generates an increased amount of oxygen vacancies, which are believed to contribute to the CO2 conversion efficiency, and among others, Zn wet impregnation resulted the most efficient process, as confirmed by X-ray photoelectron spectroscopy analysis. Electrochemical characterization and active surface area evaluation show an increase of availability of surface active sites. In particular, the introduction of Zn elemental doping results in enhanced performance for formic acid formation, in comparison to un-doped SnO2 and other doped SnO2 catalysts. At −0.99 V versus reversible hydrogen electrode, the total faradaic efficiency for CO2 conversion reaches 80%, while the partial current density is 10.3 mA cm−2. These represent a 10% and a threefold increases for faradaic efficiency and current density, respectively, with respect to the reference un-doped sample. The enhancement of these characteristics relates to the improved charge transfer and conductivity with respect to bare SnO2.

scholarly journals CO2-Induced Fibrous Zn Catalyst Promotes Electrochemical Reduction of CO2 to CO

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 477
Author(s):  
Mengquan Guo ◽  
Xiangxiang Li ◽  
Yuxin Huang ◽  
Linfa Li ◽  
Jixiao Li ◽  
...  
Keyword(s):  
Electrochemical Reduction ◽  
Active Surface ◽  
Active Surface Area ◽  
Atmospheric Conditions ◽  
X Ray Diffraction ◽  
Faradaic Efficiency ◽  
Highly Active ◽  
Fibrous Morphology ◽  
Reduction Of Co2 ◽  
Area X

The electrochemical reduction of CO2 is a promising strategy to achieve efficient conversion and utilization. In this paper, a series of Zn catalysts were prepared by electrodeposition in different atmospheric conditions (N2, CO2, H2, CO). A fibrous Zn catalyst (Zn-CO2) exhibits high electrochemical activity and stability. The Zn-CO2 catalyst shows 73.0% faradaic efficiency of CO at −1.2 V vs. RHE and the selectivity of CO almost did not change over 6 h in −1.2 V vs. RHE. The excellent selectivity and stability is attributed to the novel fibrous morphology, which increases the electrochemical active surface area. X-ray diffraction (XRD) results show that Zn-CO2 catalyst has a higher proportion of Zn (101) crystal planes, which is considered to be conducive to the production of CO. The search further demonstrates the importance of morphology control for the preparation of highly active and stable catalysts.

scholarly journals Fast operando spectroscopy tracking in situ generation of rich defects in silver nanocrystals for highly selective electrochemical CO2 reduction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xinhao Wu ◽  
Yanan Guo ◽  
Zengsen Sun ◽  
Fenghua Xie ◽  
Daqin Guan ◽  
...  
Keyword(s):  
Active Sites ◽  
Density Functional ◽  
Co2 Reduction ◽  
Density Functional Theory Calculations ◽  
Defect Concentration ◽  
Hydrogen Electrode ◽  
Efficient Catalyst ◽  
Faradaic Efficiency ◽  
Electrochemical Co2 Reduction ◽  
Cell Reactor

AbstractElectrochemical CO2 reduction (ECR) is highly attractive to curb global warming. The knowledge on the evolution of catalysts and identification of active sites during the reaction is important, but still limited. Here, we report an efficient catalyst (Ag-D) with suitable defect concentration operando formed during ECR within several minutes. Utilizing the powerful fast operando X-ray absorption spectroscopy, the evolving electronic and crystal structures are unraveled under ECR condition. The catalyst exhibits a ~100% faradaic efficiency and negligible performance degradation over a 120-hour test at a moderate overpotential of 0.7 V in an H-cell reactor and a current density of ~180 mA cm−2 at −1.0 V vs. reversible hydrogen electrode in a flow-cell reactor. Density functional theory calculations indicate that the adsorption of intermediate COOH could be enhanced and the free energy of the reaction pathways could be optimized by an appropriate defect concentration, rationalizing the experimental observation.

scholarly journals Visualisation and quantification of flooding phenomena in gas diffusion electrodes (GDEs) used for electrochemical CO2 reduction: A combined EDX/ICP–MS approach

2022 ◽  
Author(s):  
Ying Kong ◽  
Huifang Hu ◽  
Menglong Liu ◽  
Yuhui Hou ◽  
Viliam Kolivoska ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Co2 Reduction ◽  
Gas Diffusion ◽  
Reduction Reaction ◽  
Gas Diffusion Electrodes ◽  
Cross Sectional ◽  
Faradaic Efficiency ◽  
Icp Ms ◽  
Electrochemical Co2 Reduction ◽  
Current Densities

The most promising strategy to up-scale the electrochemical CO2 reduction reaction (ec-CO2RR) is based on the use of gas diffusion electrodes (GDEs) that allow current densities close to the range of 1 A/cm2 to be reached. At such high current densities, however, the flooding of the GDE cathode is often observed in CO2 electrolysers. Flooding hinders the access of CO2 to the catalyst, and by thus leaving space for (unwanted) hydrogen evolution, it usually leads to a decrease of the observable Faradaic efficiency of CO2 reduction products. To avoid flooding as much as possible has thus become one of the most important aims of to-date ec-CO2RR engineering, and robust analytical methods that can quantitatively assess flooding are now in demand. As flooding is very closely related to the formation of carbonate salts within the GDE structure, in this paper we use alkali (in particular, potassium) carbonates as a tracer of flooding. We present a novel analytical approach —based on the combination of cross-sectional energy-dispersive X-ray (EDX) mapping and inductively coupled plasma mass spectrometry (ICP--MS) analysis— that can not only visualise, but can also quantitatively describe the electrolysis time dependent flooding in GDEs, leading to a better understanding of electrolyser malfunctions.

scholarly journals Preparation of Metal Amalgam Electrodes and Their Selective Electrocatalytic CO2 Reduction for Formate Production

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 367 ◽  
Author(s):  
Syed Asad Abbas ◽  
Seong-Hoon Kim ◽  
Hamza Saleem ◽  
Sung-Hee Ahn ◽  
Kwang-Deog Jung
Keyword(s):  
Current Density ◽  
Co2 Reduction ◽  
Active Phase ◽  
Base Metals ◽  
Metallic Component ◽  
Faradaic Efficiency ◽  
Amalgam Electrode ◽  
Electrochemical Co2 Reduction ◽  
The One ◽  
Formate Production

Electrochemical CO2 reduction to produce formate ions has studied for the sustainable carbon cycle. Mercury in the liquid state is known to be an active metallic component to selectively convert CO2 to formate ions, but it is not scalable to use as an electrode in electrochemical CO2 reduction. Therefore, scalable amalgam electrodes with different base metals are tested to produce formate by an electrochemical CO2 reduction. The amalgam electrodes are prepared by the electrodeposition of Hg on the pre-electrodeposited Pd, Au, Pt and Cu nanoparticles on the glassy carbon. The formate faradaic efficiency with the Pd, Au, Pt and Cu is lower than 25%, while the one with the respective metal amalgams is higher than 50%. Pd amalgam among the tested samples shows the highest formate faradic efficiency and current density. The formate faradaic efficiency is recorded 85% at −2.1 V vs SCE and the formate current density is −6.9 mA cm−2. It is concluded that Pd2Hg5 alloy on the Pd amalgam electrode is an active phase for formate production in the electrochemical CO2 reduction.

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