Search results for "Electrochemical reduction of carbon dioxide"

A Solar Photothermocatalytic approach for the CO2 conversion: Investigation of different synergisms on CoO-CuO/Brookite TiO2-CeO2 catalysts

2022

Abstract The photoactive features of the least common polymorph of TiO2, i.e. brookite, were combined with the thermocatalytic redox ones of cerium oxide, focusing on the effects of the addition of small amounts of Co-Cu oxides for the solar CO2 conversion. By considering the characterization data, a surface segregation of the hosted metal oxides on the TiO2-CeO2 composite was evidenced, and their presence increased the amount of oxygen vacancies and improved the charge carriers separation. The bimetallic oxides-based sample was the most performing one in the photocatalytic carbon dioxide reduction at room temperature. The formation of carbon monoxide and methane was 5 and 0.5 μmol g−1h−1, …

Origin and significance of the production of carbon dioxide during the ozonization of 13C-labeled D-glucose at different pH values.

2001

Abstract [1- 13 C], [2- 13 C] and [6- 13 C] d -glucose were, respectively, ozonized in a semi-batch reactor in acidic and basic conditions. The composition of the gas phase was evaluated by on-line mass spectrometry measurements. The quantitative and isotopic analyses of the carbon dioxide formed during ozonization are presented and discussed. The data, correlated with previous literature results, clearly show that at pH 2.5 the production of carbon dioxide from C-6 and C-1 carbon atoms is nearly equivalent. Conversely, at higher pH values, CO 2 is released with a greater selectivity from the reducing end. The importance of the decarboxylation reaction in the formation of by-products with f…

Polymer Synthesis in Supercritical Carbon Dioxide

2003

It is current opinion of most of the people involved in supercritical fluids (SCFs) technology that as the end of the twentieth century has been devoted to enlarge exploitation of compressed gases in separation processes the beginning of the twenty-first will be mainly aimed to improve their utilisation as solvents for reactions.

Synthesis of dimethyl carbonate in supercritical carbon dioxide

2006

The reactivity of carbon dioxide with methanol to form dimethyl carbonate was studied in the presence of the n-butylmethoxytin compounds n-Bu3SnOCH3, n-Bu2Sn(OCH3)2 , and [n-Bu2(CH3O)Sn]2 O. The reaction occurred under solventless conditions at 423 K and was produced by an increase in CO2 pressure. This beneficial effect is primarily attributed to phase behavior. The mass transfer under liquid-vapor biphasic conditions was not limiting when the system reached the supercritical state for a CO2 pressure higher than 16 MPa. Under these conditions, CO2 acted as a reactant and a solvent.

Electrochemistry of Carbon Dioxide on Carbon Electrodes.

2016

Carbon electrodes have the advantages of being chemically inert at negative potential ranges in all media and high offset potentials for hydrogen evolution in comparison to metal electrodes, and therefore are the most suitable electrodes for electrochemistry and electrochemical conversion of CO2 into valuable chemicals. Herein we summarize on carbon electrodes the voltammetry, electrochemical and electrocatalytic CO2 reduction, as well as electron synthesis using CO2 and carbon electrodes. The electrocatalytic CO2 reduction using carbocatalyts and the future activities about electrochemical CO2 conversion are highlighted.

Leaded Bronze Alloy as a Catalyst for the Electroreduction of CO 2

2019

Electrochemical conversion of CO2 to HCOOH at tin cathode in a pressurized undivided filter-press cell

2018

Abstract The electrochemical reduction of carbon dioxide to formic acid was performed for the first time in a pressurized filter-press cell with a continuous recirculation of the electrolytic solution (0.9 L) at a tin cathode. It was shown that the performances of the system are comparable or slightly better than that of a batch system with a smaller volume (0.05 L). The selection of proper values of both current density and CO2 pressure allowed to achieve quite high values of faradaic efficiencies. Long-time electrolyses have shown that the system is stable and that it can allow to generate quite high concentrations of HCOOH (about 0.4 M).

Development of an Electrochemical Process for the Simultaneous Treatment of Wastewater and the Conversion of Carbon Dioxide to Higher Value Products

2016

Many researchers have shown that selected anodic processes allow effective treatment of a very large amount of wastewater contaminated by pollutants resistant to biological processes. In the meantime, various authors have also shown that carbon dioxide can be converted into higher value products, such as formic acid or synthesis gas, by cathodic reduction at suitable cathodes. These two processes present interesting economic potential that, however, still needs to be improved for further development at an industrial level. Herein, these two kinds of process are combined in the same cell to improve their economic feasibility. In particular, the anodic treatment of wastewater at a boron-doped…

Front Cover: (Photo)electrocatalytic Versus Heterogeneous Photocatalytic Carbon Dioxide Reduction (ChemPhotoChem 9/2021)

2021

Homogeneous Metal-Based Catalysis in Supercritical Carbon Dioxide as Reaction Medium

2016

Above 31.1 degrees C and 73.8 bar, carbon dioxide reaches the supercritical state, being transformed into a fluid (scCO(2)) that has attracted interest in the last few decades as reaction medium for several transition-metal-catalyzed organic transformations. The main feature of this fluid rests on its capability to dissolve large amounts of other gases such as hydrogen, carbon monoxide, ethylene, or even methane and light alkanes. In this manner, very high concentrations of these reactants are available for catalysis. In this contribution a review of the main achievements of the use of transition-metal complexes as catalysts in scCO(2) is presented.