The formation of surface stable anion vacancy states at CeO2 ultra-small crystallite dimensions

para Substituted chloro, bromo, and nitro derivatives of 2-acyl-5-phenylfurane are reduced polarographically in a one-electron wave to the corresponding anion radicals, which were studied by the EPR method. The reduction of nitro derivatives, studied by the Kalousek switch, is reversible and leads to a stable anion radical with an unpaired electron center on the nitrogen nucleus; the reduction of the halogen derivatives is only partly reversible and leads to unstable ketyl radicals. The bromo derivatives give polarographic maxima typical for concurrent reactions.

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Toward alkaline-stable anion exchange membranes in fuel cells: cycloaliphatic quaternary ammonium-based anion conductors

Electrochemical Energy Reviews ◽

10.1007/s41918-021-00105-7 ◽

2021 ◽

Author(s):

Jiandang Xue ◽

Junfeng Zhang ◽

Xin Liu ◽

Tong Huang ◽

Haifei Jiang ◽

...

Keyword(s):

Fuel Cells ◽

Anion Exchange ◽

Quaternary Ammonium ◽

Anion Exchange Membranes ◽

Stable Anion

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Double sulfur vacancies by lithium tuning enhance CO2 electroreduction to n-propanol

Nature Communications ◽

10.1038/s41467-021-21901-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Chen Peng ◽

Gan Luo ◽

Junbo Zhang ◽

Menghuan Chen ◽

Zhiqiang Wang ◽

...

Keyword(s):

Anion Vacancy ◽

High Energy ◽

Hydrogen Electrode ◽

Cycle Number ◽

Faradaic Efficiency ◽

Flow Cells ◽

Forming Mechanism ◽

Co2 Electroreduction ◽

Tuning Strategy ◽

Partial Current

AbstractElectrochemical CO2 reduction can produce valuable products with high energy densities but the process is plagued by poor selectivities and low yields. Propanol represents a challenging product to obtain due to the complicated C3 forming mechanism that requires both stabilization of *C2 intermediates and subsequent C1–C2 coupling. Herein, density function theory calculations revealed that double sulfur vacancies formed on hexagonal copper sulfide can feature as efficient electrocatalytic centers for stabilizing both CO* and OCCO* dimer, and further CO–OCCO coupling to form C3 species, which cannot be realized on CuS with single or no sulfur vacancies. The double sulfur vacancies were then experimentally synthesized by an electrochemical lithium tuning strategy, during which the density of sulfur vacancies was well-tuned by the charge/discharge cycle number. The double sulfur vacancy-rich CuS catalyst exhibited a Faradaic efficiency toward n-propanol of 15.4 ± 1% at −1.05 V versus reversible hydrogen electrode in H-cells, and a high partial current density of 9.9 mA cm−2 at −0.85 V in flow-cells, comparable to the best reported electrochemical CO2 reduction toward n-propanol. Our work suggests an attractive approach to create anion vacancy pairs as catalytic centers for multi-carbon-products.

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Combining Soft- and Hard-Templating Approaches in MWW-Type Zeolites

Molecules ◽

10.3390/molecules25153335 ◽

2020 ◽

Vol 25 (15) ◽

pp. 3335

Author(s):

Anderson Joel Schwanke ◽

Jaíne Fernandes Gomes ◽

Katia Bernardo-Gusmão ◽

Sibele Pergher

Keyword(s):

Electron Microscopy ◽

X Ray Diffraction ◽

N2 Adsorption ◽

X Ray ◽

Carbon Particles ◽

Soft Templating ◽

Small Crystallite ◽

Scanning Electron ◽

Soft Templates ◽

Hard Templating

A combination of hard-templating (HT) and soft-templating (ST) approaches was studied to obtain MWW-type materials with intermediate physicochemical properties. The HT methodology involved the introduction of carbon particles as hard templates during gel synthesis to obtain a layered zeolitic precursor (LZP) with particles possessing a microspherical morphology. The LZP obtained was treated with surfactants as soft templates to expand the layers of the LZP, followed by a pillaring procedure. The materials were characterized by X-ray diffraction, transmission and scanning electron microscopy, elemental analysis and N2 adsorption. The results demonstrate that the obtained material possesses intermediate properties from both approaches, with interparticle mesopores/macropores and pore sizes between 18 and 46 Å. However, the ST procedure causes a partial disruption of some microspheres, forming small crystallite aggregates, and results in a decrease in the number of interparticle mesopores/macropores previously formed by the HT method.

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