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.

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.

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.

Electrochemical CO2 reduction with low overpotential by a poly(4-vinylpyridine) electrode for application to artificial photosynthesis

2017 ◽  
Vol 198 ◽  
pp. 409-418 ◽  
Author(s):  
Hohyun Jeong ◽  
Myung Jong Kang ◽  
Hyeyeong Jung ◽  
Young Soo Kang
Keyword(s):  
Charge Transfer ◽  
Current Density ◽  
Electrochemical Impedance ◽  
Catalytic Properties ◽  
Co2 Reduction ◽  
Surface Concentration ◽  
Reduction Reaction ◽  
Pt Electrodes ◽  
Electrochemical Co2 Reduction ◽  
Low Overpotential

Pyridine molecules have been used as a catalyst to reduce the activation energy of the CO2 reduction reaction. It has been reported that CO2 is reduced by pyridine catalysts at low overpotential around −0.58 V vs. SCE. Poly(4-vinylpyridine), which has pyridine functional groups shows similar catalytic properties to reduce CO2 at low overpotential like pyridinium catalysts. Different thickness of P(4-VP) coated Pt electrodes were analyzed to determine the catalytic properties for CO2 reduction. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy methods showed the catalytic CO2 reduction properties of a P(4-VP)/Pt electrode. Thin P(4-VP)/Pt film showed a low current density of −0.16 mA cm−2 under CO2 atmosphere and the current density reached −0.45 mA cm−2 with increase of the P(4-VP) thickness. The increase of current density was explained by an increased surface concentration of adsorbed pyridinium groups of the thick P(4-VP) layer. Nyquist plots also showed decrease of impedance with increase of the P(4-VP) layer indicating fast charge transfer between Pt and the P(4-VP) layer due to the increase of hybrid ionic complex formation on the Pt surface. However, charge transfer is restricted when the P(4-VP) layer becomes more thick because of slowed protonation of pyridine groups adjacent to the Pt surface due to the suppressed permeability of electrolyte solution into the PVP membrane. This electrochemical observation provides a new aspect of P(4-VP) polymer for CO2 reduction.

(Invited) A Full Carbon Balance Analysis on High Current Density Electrochemical CO2 Reduction Reactors with Cu Catalysts

2020 ◽  
Vol MA2020-01 (36) ◽  
pp. 1497-1497
Author(s):  
Brian Seger ◽  
Ming Ma ◽  
Ezra L Clark ◽  
Kasper Therkildsen ◽  
Ib Chorkendorff
Keyword(s):  
Current Density ◽  
Carbon Balance ◽  
High Current Density ◽  
Co2 Reduction ◽  
High Current ◽  
Electrochemical Co2 Reduction ◽  
Balance Analysis ◽  
Cu 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.

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