Ammonium ion-promoted electrochemical production of synthetic gas from water and carbon dioxide on a fluorine-doped tin oxide electrode

2021 ◽  
Vol 57 (12) ◽  
pp. 1438-1441
Author(s):  
Shin-ichi Naya ◽  
Hisayoshi Yoshioka ◽  
Hiroaki Tada
Keyword(s):  
Carbon Dioxide ◽  
Tin Oxide ◽  
Reaction Rate ◽  
Reduction Reaction ◽  
Ammonium Ion ◽  
Oxide Electrode ◽  
Ammonium Ions ◽  
Synthetic Gas ◽  
Electrochemical Production

In situ generated Sn nanoparticles on fluorine-doped tin oxide act as an electrocatalyst for the CO2 reduction reaction to efficiently and stably produce synthetic gas from water and carbon dioxide with the reaction rate drastically enhanced by the addition of ammonium ions.

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)...

In-Situ Leaching of South Texas Uranium Ores-Part 2: Oxidative Removal of Adsorbed Ammonium Ions With Sodium Hypochlorite

1983 ◽  
Vol 23 (02) ◽  
pp. 387-396 ◽  
Author(s):  
J.M. Paul ◽  
W.F. Johnson ◽  
A. Fletcher ◽  
P.B. Venuto
Keyword(s):  
Cation Exchange ◽  
Sodium Hypochlorite ◽  
Geographical Area ◽  
Ammonium Bicarbonate ◽  
South Texas ◽  
Ion Concentration ◽  
Ammonium Ion ◽  
Side Reactions ◽  
Ammonium Ions

Abstract This paper reports a laboratory study of the oxidative destruction by sodium hypochlorite (NaOCl) of ammonium ions adsorbed on relatively reduced south Texas uranium ore. Included are an assessment of reaction stoichiometry, determination of some major reaction pathways and side reactions, and identification of several pathways and side reactions, and identification of several intermediates. Adsorbed ammonium ions were completely removed by 0.5 % NaOCl, with the concentration of NH3 in the effluent falling to a very low value after 10 to 15 PV NaOCl oxidant. A small fraction (5 to 10%) of NaOCl was utilized in reacting with NH3. After the NH3 was nearly depleted, mono-, di-, and trichloramines, the expected intermediates in NaOCl oxidation of NH3, were observed. Chloramine decomposition studies showed that all three decomposed completely within 12 days. Since the ore was relatively highly reducing, the major pan of the NaOCl was, not unexpectedly, consumed in side reactions. Substantial quantities of sulfate, reflecting oxidation of sulfide minerals such as pyrite, were formed, large amounts of uranium were leached out, and substantial amounts of calcium and magnesium ions were also produced during the presaturation with NH4HCO3 preceding the oxidation stage. Introduction A leachate that has sometimes been used for in-situ leaching of uranium ores is a solution of ammonium bicarbonate (NH4HCO3) containing an oxidant-usually hydrogen peroxide (H2O2) or oxygen (O2). The ammonium ion (NH4+) introduced into the ore body upon injection of this leachate is exchanged for cations such as calcium (Ca+2 ) and sodium (Na+), which are associated with mineral species in the formation possessing available cation exchange sites. As the indigenous groundwaters reinvade the leached zone, the adsorption process is reversed with NH4+ ions being displaced from process is reversed with NH4+ ions being displaced from the cation exchange sites and returned to the ground-waters. In general, this latter process maintains the ammonia (NH3 (or NH4+ ion) concentration well above the baseline (pre-mining) value in groundwater for extended periods of time in waters produced from wells in or near the mined zone following cessation of leachate injection. Prior to abandonment of an in-situ leach-mining site by the operator, satisfactory restoration of groundwater quality must be demonstrated. Requirements for this demonstration vary with the geographical area. A summary of applicable regulations has been provided by Kasper et al. A review of the state of restoration demonstrations to Sept. 1979 has been given by Tiepel. Most of the in-situ leach operations in south Texas have been conducted in aquifers containing indigenous waters with TDS contents in the 700- to 3,000-ppm range. Ca+ 2, magnesium (Mg+2), and bicarbonate ion (HCO3 ) concentrations are high in these slightly alkaline waters. These equilibrium water compositions indicate that an appreciable fraction of the interlayer ion exchange sites of the smectite clays in the formation are occupied by Ca+2 or Mg+2 ions. SPEJ P. 387

Mathematical Modeling of the Stream Method of Underground Coal Gasification

1975 ◽  
Vol 15 (05) ◽  
pp. 425-436 ◽  
Author(s):  
C.F. Magnani ◽  
S.M. Farouq Ali
Keyword(s):  
Mathematical Modeling ◽  
Carbon Dioxide ◽  
Coal Seam ◽  
Coal Gasification ◽  
Underground Coal Gasification ◽  
Hydrocarbon Gases ◽  
Underground Gasification ◽  
Performance Curves ◽  
Synthetic Gas

Abstract This investigation focuses on mathematical modeling of the process of underground gasification of coal by the stream method. A one-dimensional, steady-state model consisting of five coupled differential equations was formulated, and the solution, extracted analytically, was used to develop closed-form expressions for the parameters influencing coal gasification. The model then was used for interpreting field performance curves, predicting the results of The performance curves, predicting the results of The field tests, and ascertaining the over-all process sensitivity to the input variables. The usefulness of the model was shown by establishing the parameters influencing the success or failure of parameters influencing the success or failure of an underground gasification project. Introduction One method of eliminating many of the technological and environmental difficulties encountered during the production of synthetic gas through aboveground coal gasification involves gasifying cod in situ. This process, known as underground coal gasification, was first proposed in 1868 by Sir William Siemens and is based on the controlled combustion of coal in situ. This in-situ combustion results in the production of an artificial or synthetic gas that is rich in carbon dioxide, carbon monoxide, hydrogen, and hydrocarbon gases. Despite the fact that reaction stoichiometry is a moot element of underground coal gasification, it is nonetheless believed thatcarbon dioxide is formed by the partial oxidation of coal,carbon monoxide is generated by the subsequent reduction of carbon dioxide, andthe hydrogen and hydrocarbon gases result from the water-gas reaction and carbonization of coal, respectively. To effect the controlled combustion of coal in situ, the coal seam first must be ignited and a means must be provided for supporting combustion (through injection of a suitable gasification agent) and producing the gases generated underground. Fig. 1 presents a schematic diagram of an underground gasification system that complies with these requirements. This approach to gasifying coal is known as the stream or channel method and necessitates drilling two parallel galleries, one serving as an injection gas inlet and the other as a producer gas outlet. These wells are then linked by a borehole drilled horizontally through the coal seam. Ignition occurs in the coal seam at the gas inlet and proceeds in the direction of flow. The combustion front thus generated moves essentially perpendicular to the direction of gas flow. perpendicular to the direction of gas flow.Since the technological inception of underground gasification, over 1,500 publications have appeared in the literature that bear testimony to the absence of a complete, legitimate, theoretical analysis of the underground gasification process. Given this observation, it is the basis of this paper that progress in underground coal-gasification research progress in underground coal-gasification research has suffered from the absence of "interpretative theory"; that is, it has suffered from a lack of logical, physical, and mathematical analysis of the governing and underlying aerothermochemical principles. The difficulties in formulating a principles. The difficulties in formulating a mathematical model adequately describing the numerous phenomena involved during coal gasification are indeed formidable. SPEJ P. 425

Three-dimensional hydrogel-modified indium tin oxide electrode with enhanced performance for in situ electrochemical detection of extracellular H2O2

The Analyst ◽  
2021 ◽  
Author(s):  
Shiying Zhou ◽  
Xianfeng Wang ◽  
Liuyi Jiang ◽  
Human Sun ◽  
Danqun Huo ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Electrochemical Detection ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Electrochemical Sensors ◽  
Three Dimensional ◽  
Oxide Electrode ◽  
Indium Tin Oxide Electrode ◽  
H2o2 Reduction

Two different electrochemical sensors (Hemin-G4/Au/GCE and Hemin-G4/Au/ITO) were developed and applied to explore the electrocatalytic capacity of H2O2 reduction. Due to the excellent catalytic activity of Hemin-G4 and the high...

Self-supported mesoscopic tin oxide nanofilms for electrocatalytic reduction of carbon dioxide to formate

2021 ◽  
Author(s):  
Juwon Jeong ◽  
Jin Soo Kang ◽  
Heejong Shin ◽  
Soo Hong Lee ◽  
Junghwan Jang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Surface Area ◽  
Tin Oxide ◽  
Co2 Reduction ◽  
Reduction Reaction ◽  
Electrochemical Process ◽  
Sno2 Film ◽  
Large Surface Area ◽  
Electrocatalytic Reduction ◽  
Co2 Reduction Reaction

Here we report self-supported SnO2 nanofilm prepared by a robust electrochemical process as an electrocatalyst for CO2 reduction reaction. SnO2 film had large surface area originating from its nano-architecture and...

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.

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