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![Some possible chemical transformations of carbon dioxide. [Reproduced from Ref. 7 with permission from Consultancy Development Centre, New Delhi].](profile/Balasubramanian-Viswanathan/publication/266351993/figure/fig1/AS:392177294299136@1470513761020/Some-possible-chemical-transformations-of-carbon-dioxide-Reproduced-from-Ref-7-with.png)
Some possible chemical transformations of carbon dioxide. [Reproduced from Ref. 7 with permission from Consultancy Development Centre, New Delhi].
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It is known that carbon dioxide undergoes electrochemical reduction to a variety of products like CO, hydrocarbons and alcohols on metallic surfaces and that the nature of the metal has a role to play in the observed selectivity of products. Rationalization of the results obtained on different metallic surfaces and accounting for the selectivity ha...
Citations
... In recent years, the increasing demands of fossil fuel and a continuous increasing the atmospheric CO 2 levels demands intensive carbon management. Consequently, a variety of photocatalytic/ electrocatalytic process has been presumed by the researchers for the intensive carbon management [3][4][5]. For instance, some researcher has reported an electrochemical method to reduce the level of CO 2 on a metallic surface [4,5]. ...
... Consequently, a variety of photocatalytic/ electrocatalytic process has been presumed by the researchers for the intensive carbon management [3][4][5]. For instance, some researcher has reported an electrochemical method to reduce the level of CO 2 on a metallic surface [4,5]. The electrochemical reduction of CO 2 into useful solar chemicals is clearly depicted in Scheme 1. ...
The consumption of carbon dioxide (CO2) for direct solar fuel productions and synthesis of fine solar chemicals are gaining leading significance due to the shortage of fossil-fuel and global warming worldwide. Therefore, herein, we report the synthesis and development of solar light harvesting bamboo-shape magnesium tetraphenyl porphyrin based framework (Mg-TPPBF) photocatalyst. The development of Mg-TPPBF photocatalyst-biocatalyst bonded system as a solar light harvesting photocatalyst functions in a extremely efficient manner, increasing to high regeneration of NADH (73.9%), followed by its utilization in exclusive amount of formic acid (HCOOH) production (197.2 μmol) from CO 2. The Mg-TPPBF photocatalyst also enables in consecutive C-S/C-N bonds formation with high yield (~96-99%) and selectivity (~97-99%) under solar light with excellent reusability. The current research work highlights the enlargement and application of Mg-TPPBF photocatalyst for direct solar fuel production from CO 2 and fine solar chemical synthesis.
... All living organisms convert carbon dioxide, by autotrophic consumption or heterotrophic production, and measurement of CO 2 concentration changes are thus essential in many scientific and medical studies. Very large investments are currently made to lower the anthropogenic emission of CO 2 , and even to transform the CO 2 now being emitted into organic compounds by chemical processes [1]. ...
... Oxygen is reduced (to superoxide [8]) at much less negative potentials than CO 2 , and any protic chemical species entering through the membrane, such as water, may also be reduced. A large variety of CO 2 reduction products may be formed in the presence of water or any other reactive chemical species such as alkenes and alkynes [1], and even trace amounts of water contamination in an aprotic electrolyte may affect the outcome of the cathodic reduction [11]. A negatively charged gold-plated front membrane has been used to reduce O 2 before it entered the cathodic chamber of a CO 2 sensor through a second membrane, but a reasonable response was only obtained above 2% CO 2 , and the response to changes in CO 2 concentration was very slow [12]. ...
A simple method to measure dissolved CO2 at a microscale would be beneficial for many scientific and medical applications. A simple amperometic microsensor for CO2 with a 20-100 µm wide tip was developed by placing a layer of acidic O2 trap solution containing Cr2+ in front of a Clark-type electrochemical sensor. The Clark-type sensor contains a Ag cathode in an ionic liquid, and also a Ag guard cathode behind the sensing cathode to prevent interference from reducible contaminants in the ionic liquid. The constructed sensors exhibited linear response over relatively large intervals of CO2 partial pressure, but for CO2 partial pressures of < 20 Pa the response was only about 60% of that observed at 20-1000 Pa. The slope of the calibration curve at 2-6 kPa was about 80% of the slope from 0-1 kPa. A high baseline signal caused by water diffusing through the membrane into the ionic liquid was avoided by making very conical sensors so that the water concentration around the cathode was kept low by diffusional transport into the bulk reservoir of ionic liquid, but elevated zero currents by a factor of about two was often observed for sensors more than 1 month old. The lifetime of the sensor by continuous operation can be more than 4 months, but with a slow decrease in sensitivity that may be caused by lower membrane permeability. Use of the sensor was demonstrated by measuring CO2 dynamics in the thallus of a red algae along with variations in O2 and pH.
... Zum einen Katalysatoren und Mechanismus [38,39,40], zum zweiten das Elektrodendesign [41,42,43] und zuletzt Aufbau und Funktionsweise der Elektrolysezellen [41,44]. An dieser Stelle lassen sich folgende Reviews empfehlen, die eine gute Übersicht über das Thema der Kohlendioxidelektrolyse geben [39,45,46,47,48,49,50,51,52] [46] stellt man fest, dass diese sehr eng beieinander liegen [46,48] Energieversorgung und muss weiter erforscht und gefördert werden. ...
... 14 It is particularly important to highlight that the broken CO 2 geometry is related to the possibility to convert it in other chemical row materials. 52 We have noted that for some systems, such as [TMA] + -CO 2 , the C−H bond is shortened by 0.001 Å with complexation, occasioned by the carbon radius increasing and consequent reduction of the H radius. As described by Grabowski,53 (Table 2). ...
In recent years, the global climate change is in evidence and is almost a consensus that is caused by the greenhouse gases emissions. As an alternative to reduce these emissions is the Carbon Capture and Storage (CCS), which employs solvents based on amine compounds. In this scene, Ionic Liquids (IL) has been investigated in a greater extent to this application. In this work, we make an evaluation of interactions between gases (CO2, SO2 and H2S) and anion/cation from IL, as well as cation-anion interactions. For this, quantum calculations in vacuum were performed at B3LYP/6-311+G** level of theory and using the M06-2X functional, where dispersion effects are considered. Among the well-studied systems based on imidazolium cations and fluorinated anions, we also studied the tetraalkylammonium, tetraalkylphosphonium, ether-functionalized imidazolium based systems and tetrahexylammonium bis(trifluoromethanesulfonyl)imide, [THA][Tf2N], as a potential prototype. The ion pairs evaluated include [Tf2N]--based IL, with alkyl chain varying from [C1mim]+ to [C8mim]+ and [C1mim]+-based IL. We found that the anion becomes more available to interact with gas with the weakening of the cation-anion interaction. [THA][Tf2N] has binding energy of -274.89 kJ/mol at B3LYP/6-311+G** level of theory, which is considered energetically interesting to gas capture applications.
... (1) as a non toxic feedstock which is used to replace harmful chemicals, (2) raw material for the production of some polymers, (3) as an alternate and efficient feed stock, and (4) production of new chemicals which could positively impact carbon balance [2]. The electrochemical reduction process utilizes only gaseous carbon dioxide and possibly protons from aqueous electrolytes and yields a variety of hydrocarbon products. ...
Carbon dioxide a common greenhouse gas is converted to value added products such as methane and ethane by electrochemical reduction at a surface oxidized copper electrode. The product yield and the relationships between the surface chemistry and reaction behavior were investigated. Ethane was observed as a dominant product at the surface oxidized Cu electrodes suggesting that Cu (I) species play a critical role in selectivity towards C2 species.
Solar reforming of hydrocarbons from the photocatalytic reduction of carbon dioxide is receiving considerable attention worldwide due to both the simplicity of the process and the easy manageability of the system. The methods of reducing carbon dioxide can be electrochemical, photochemical, photocatalytic, photoelectrochemical, and biochemical. This chapter summarizes the various means of activation to reduce carbon dioxide. It examines the heterogeneous photocatalytic reduction of carbon dioxide by semiconducting materials. The chapter presents a brief description of nanomaterials. It focuses on how useful they are for the photocatalytic reduction of carbon dioxide. It is realized that in any successful attempt to make this process viable commercially, the selection of photocatalytic material is an important requirement. The chapter provides a list of semiconductors with data on bandgap, valence band maximum, and conduction band minimum. Carbon dioxide is chemically inert, has a closed shell electronic configuration, and is linear in structure.
Energy generation from fossil fuels is a major source for greenhouse gases, especially CO2, which has been associated to the global climate change. On the other hand, SO2 e H2S have other sources, such as volcanic activity and natural gas fields, respectively.
In this context, Ionic Liquids (IL) are considered promising materials for gas capture and separation, as they present advantageous properties that include: low vapor pressure, low melting points, high stability and ability to dissolute gases. In this thesis, it has been evaluated the interactions between IL and CO2, SO2 and H2S gases. In the first step, anion-gas and cation-gas interactions have been investigated to understand the role of cations and anions in the gas-IL interactions. In particular, it has been considered imidazolium-based IL with a with a varying alkyl chain, tetraalkylammonium and tetraalkylphosphonium-based IL and imidazolium-functionalized cations with ether groups, whereas anions include halide, fluoride, acetate and sulfate/alkylsulfate. In the second step, cation-anion interactions and their effects over gas solubility have been evaluated, where the combinations were [C1mim]X, where X= [BF4]-, [Tf2N]-, [MeSO4]-, [PF6]-, [EtSO4]-, [Cnmim][Tf2N] and ion pairs with functionalized cations, here called [C1Odmim][Tf2N] and [C1Oemim][Tf2N]. In the last step, CO2-ion pair interactions were assessed in selected systems, i. e., [Cnmim][Tf2N]. Here, it is also proposed six novel ion pairs, which correspond to functionalized systems with ether groups and the system with best values for binding energies. In this thesis, the ab initio calculations were carried out in Gaussian 09 using the B3LYP and M06-2X levels of theory and 6-311+G** basis set.
Keywords: Gas Capture. Ionic Liquids. Solubility. Intermolecular Interactions.
Computational Simulations.
This master's thesis was written in Portuguese, but the results were published in the Journal of Physical Chemistry C, in 2014.
Link: https://pubs.acs.org/doi/10.1021/jp503293j
The alleviation of greenhouse gas (GHG) emissions is a major provoke for waste management and composting industry in expect of the global warming regards. Carbon dioxide and GHG emission reduction during composting have been noticed as one of the important steps toward environmental engineering. To keep GHG below the standard limit, huge quantity CO2 emissions’ reduction through dissociation and exploitation will be necessary. In addition, CO2 generation reduction will uprise an unique methods option when expanse of CO2 emissions is considered to be enclosed in the waste collection, separation, and transportation price. This chapter with consideration the possible CO2 reduction/fixation biotechnology and it’s utilization via biochemical engineering as by-products in composting factory. Many CO2 reduction and adsorption methods such as organic, inorganic and microbial adsorption and transformation to CO2, oxidative dehydrogenation, hydrogenation, and polymerization are extensively considered. The methods’ limitation and recent advancement and accomplished fact are also summarized.
In this chapter, preliminary discussion on the need for mitigation of greenhouse gas emissions in today’s scenario is emphasized, followed by the foundation to the conversion of CO2 into useful chemicals. Various techniques employed for CO2 sequestration are introduced, and in the midst of these approaches, electrochemical reduction of CO2 is emphasized, owing to its advantages in product selectivity, operation at ambient conditions without supplementary chemical requirements, environmental compatibility, relatively simple modularity and quick scalability. Different types of catalysts reported in the literature for activating and reducing CO2 are critically analysed. To start with, metallic electrodes in aqueous solutions and nanoporous materials are discussed. The reaction mechanism and effect of supporting electrolytes, pressure, and temperature are summarized. Combination of various techniques such as bio-electrochemical reduction and photocatalytic technologies have been accentuated. Furthermore, limitations and outlook of electrochemical reduction of CO2 are presented, in which development of modules similar to that of commercially available H2O electrolysers could pave the way for commercialization of electrocatalytic reduction of CO2.
The motivation for this presentation is to examine why photo-catalytic reduction of carbon dioxide to fuel precursors and fuels has not yielded the desired levels of activity in spite of the intense pace of research in the recent years? Main issues, namely the relevance of residual carbon for the reduction products, inadequacy of analysis techniques existing, partial nature of the measures used to denote the activity and also suitably adjusting (increasing) the reducing power of the excited electron, have been identified, even though there may be other reasons for this disappointing progress. The remedial measures suggested may facilitate the progress in realizing this process as a viable one.
