scholarly journals Morphology and mechanism of highly selective Cu(II) oxide nanosheet catalysts for carbon dioxide electroreduction

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xingli Wang ◽  
Katharina Klingan ◽  
Malte Klingenhof ◽  
Tim Möller ◽  
Jorge Ferreira de Araújo ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Gas Diffusion ◽  
Reduction Reaction ◽  
Flow Conditions ◽  
Differential Electrochemical Mass Spectrometry ◽  
Transmission Electron ◽  
Cu Catalysts ◽  
Shape Controlled ◽  
X Ray Absorption

AbstractCu oxides catalyze the electrochemical carbon dioxide reduction reaction (CO2RR) to hydrocarbons and oxygenates with favorable selectivity. Among them, the shape-controlled Cu oxide cubes have been most widely studied. In contrast, we report on novel 2-dimensional (2D) Cu(II) oxide nanosheet (CuO NS) catalysts with high C2+ products, selectivities (> 400 mA cm−2) in gas diffusion electrodes (GDE) at industrially relevant currents and neutral pH. Under applied bias, the (001)-orientated CuO NS slowly evolve into highly branched, metallic Cu0 dendrites that appear as a general dominant morphology under electrolyte flow conditions, as attested by operando X-ray absorption spectroscopy and in situ electrochemical transmission electron microscopy (TEM). Millisecond-resolved differential electrochemical mass spectrometry (DEMS) track a previously unavailable set of product onset potentials. While the close mechanistic relation between CO and C2H4 was thereby confirmed, the DEMS data help uncover an unexpected mechanistic link between CH4 and ethanol. We demonstrate evidence that adsorbed methyl species, *CH3, serve as common intermediates of both CH3H and CH3CH2OH and possibly of other CH3-R products via a previously overlooked pathway at (110) steps adjacent to (100) terraces at larger overpotentials. Our mechanistic conclusions challenge and refine our current mechanistic understanding of the CO2 electrolysis on Cu catalysts.

scholarly journals Electrokinetic and in situ spectroscopic investigations of CO electrochemical reduction on copper

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Li ◽  
Xiaoxia Chang ◽  
Haochen Zhang ◽  
Arnav S. Malkani ◽  
Mu-jeng Cheng ◽  
...  
Keyword(s):  
Mass Transport ◽  
Active Sites ◽  
Gas Diffusion ◽  
Reduction Reaction ◽  
Adsorbed Hydrogen ◽  
Diffusion Type ◽  
Proton Coupled Electron Transfer ◽  
Alkaline Electrolytes ◽  
Reaction Orders

AbstractRigorous electrokinetic results are key to understanding the reaction mechanisms in the electrochemical CO reduction reaction (CORR), however, most reported results are compromised by the CO mass transport limitation. In this work, we determined mass transport-free CORR kinetics by employing a gas-diffusion type electrode and identified dependence of catalyst surface speciation on the electrolyte pH using in-situ surface enhanced vibrational spectroscopies. Based on the measured Tafel slopes and reaction orders, we demonstrate that the formation rates of C2+ products are most likely limited by the dimerization of CO adsorbate. CH4 production is limited by the CO hydrogenation step via a proton coupled electron transfer and a chemical hydrogenation step of CO by adsorbed hydrogen atom in weakly (7 < pH < 11) and strongly (pH > 11) alkaline electrolytes, respectively. Further, CH4 and C2+ products are likely formed on distinct types of active sites.

In-situ growth of Cu2O with honeycomb structure on roughed graphite paper for efficient electroreduction of CO2 to C2H4

2021 ◽  
Author(s):  
Zuoyu Yan ◽  
Xiuxiu Wang ◽  
Yang Tan ◽  
Aihua Liu ◽  
Fenqiang Luo ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Cuprous Oxide ◽  
Carbon Dioxide Reduction ◽  
Honeycomb Structure ◽  
Reduction Reaction ◽  
In Situ Growth

Metals and their alloys based electrocatalysts continue to attract great attention for electrochemical carbon dioxide reduction reaction (CO2RR). Herein, cuprous oxide (Cu2O) supported on N-doped flexible roughed graphite paper (NGP)...

Size dependent behavior of Fe3O4crystals during electrochemical (de)lithiation: an in situ X-ray diffraction, ex situ X-ray absorption spectroscopy, transmission electron microscopy and theoretical investigation

2017 ◽  
Vol 19 (31) ◽  
pp. 20867-20880 ◽  
Author(s):  
David C. Bock ◽  
Christopher J. Pelliccione ◽  
Wei Zhang ◽  
Janis Timoshenko ◽  
K. W. Knehr ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
X Ray ◽  
Size Dependent ◽  
Transmission Electron ◽  
Dependent Behavior ◽  
X Ray Absorption

Crystal and atomic structural changes of Fe3O4upon electrochemical (de)lithiation were determined.

scholarly journals CO2 Hydrogenation to Olefin-Rich Hydrocarbons Over Fe-Cu Bimetallic Catalysts: An Investigation of Fe-Cu Interaction and Surface Species

2021 ◽  
Vol 3 ◽  
Author(s):  
Wenjia Wang ◽  
Xiaoxing Wang ◽  
Guanghui Zhang ◽  
Ke Wang ◽  
Fu Zhang ◽  
...  
Keyword(s):  
Product Distribution ◽  
Distribution Analysis ◽  
Cu Alloy ◽  
Cu Catalyst ◽  
Reaction Performance ◽  
Cu Catalysts ◽  
Adsorbed Co ◽  
X Ray Absorption ◽  
Indirect Route

Previously, we reported a strong Fe-Cu synergy in CO2 hydrogenation to olefin-rich C2+ hydrocarbons over the γ-Al2O3 supported bimetallic Fe-Cu catalysts. In this work, we aimed to clarify such a synergy by investigating the catalyst structure, Fe-Cu interaction, and catalyst surface properties through a series of characterizations. H2-TPR results showed that the addition of Cu made both Fe and Cu easier to reduce via the strong interaction between Fe and Cu. It was further confirmed by X-ray absorption spectroscopy (XAS) and TEM, which showed the presence of metallic Fe and Fe-Cu alloy phases in the reduced Fe-Cu(0.17) catalyst induced by Cu addition. By correlating TPD results with the reaction performance, we found that the addition of Cu enhanced both the moderately and strongly adsorbed H2 and CO2 species, consequently enhanced CO2 conversion and C2+ selectivity. Adding K increased the adsorbed-CO2/adsorbed-H2 ratio by greatly enhancing the moderately and strongly adsorbed CO2 and slightly suppressing the moderately and strongly adsorbed H2, resulting in a significantly increased O/P ratio in the produced hydrocarbons. The product distribution analysis and in situ DRIFTS suggested that CO2 hydrogenation over the Fe-Cu catalyst involved both an indirect route with CO as the primary product and a direct route to higher hydrocarbons.

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