Carbon dioxide electrocatalytic reduction

Reduction of Carbon Dioxide Electrocatalytic Properties of Carbon 19... 

A v ety of reactions are catalyzed by electrochemically generated Ni(0) (62). Electrochemical reduction of Ni(bipy)3Br2 affords a reagent that couples acid chlorides and alkyl or aryl halides to form unsymmetrical ketones (63). Symmetrical ketones are formed from alkyl halides and carbon dioxide (64). Reductive electrochemical carboxylation of terminal alkynes, enynes and diynes can be accomplished with 10% Ni(bipy)3(Bp4)2 in DMF (65-68). Terminal allies lead selectively to a-substituted acrylic acids. Electrocatalytic hydrogenation on hydrogen-active electrodes has been reviewed (69). Radical cyclizations of vinyl, alkyl and aryl radicals can be carried out by indirect electrochemical reduction with a Ni(II) complex as a mediator (70). 

Electrocatalytic reduction of carbon dioxide to Q-C3 hydrocarbons with less than 0.2% electrochemical yield was reported154 at pH 7 in the presence of pyrocatechol, TiCl3, and Na2Mo04 at -1.55 V versus SCE. 

Low-valent rhenium complexes are effective in the catalytic reduction of carbon dioxide. The conversion can be accomplished photolytically or electrochemically and is of interest with regard to fuel production and greenhouse gas remediation [9]. Electrocatalytic reduction of CO2 to CO is initiated by the reduction of fac-Re(bpy)(CO)3Cl or a related complex and can be accomplished in homogeneous solution [54, 55] or on a polymer-modified electrode surface [56]. Catalytic current... 

Fisher and Eisenberg (107) have reported on the electrocatalytic reduction of carbon dioxide using macrocycle complexes of nickel and cobalt (e.g., complex 27). An indirect electrochemical reduction of C02 was ac-... 

Morris AJ, McGibbon RT, Bocarsly AB. Electrocatalytic carbon dioxide activation the rate-determining step of pyridinium-catalyzed CO2 reduction. ChemSusChem. 2011 4 191-6. 

Isse, A.A., Ferlin, M.G. and Gennaro, A. (2005a) Electrocatalytic reduction of arylethyl chlorides at silver cathodes in the presence of carbon dioxide Synthesis of 2-arylpropanoic acids. J. Electroanal. Chem. 581, 38 15. 

Fig. 18. Ligand architectures for coordinative carbon dioxide activation structure of the biotin-C02 coenzyme (17) involved in many biological carboxylations (146). Proposed pyridinium-COz adduct (18) accelerating electrocatalytic carbon dioxide reduction processes (147).

The electrocatalytic behavior of cathodes appears to play a crucial role in the reduction of carbon dioxide. To find more efficient catalysts, detailed mechanistic studies of CO2 reduction are needed. Further studies could also concentrate on the investigation of different electrolytes as well as different catalysts delivering products of choice, such as alcohols. 

Another important reaction is the coupling of two carbon dioxide molecules at the carbon atoms to give oxalate. This process appears to be a side reaction in some electrocatalytic reductions yet it has... 

Electrocatalysis at metal electrodes in aqueous (1.2) and non-aqueous ( ) solvents, phthalocyanine ( ) and ruthenium ( ) coated carbon, n-type semiconductors (6.7.8),and photocathodes (9,10) have been explored in an effort to develop effective catalysts for the synthesis of reduced products from carbon dioxide. The electrocatalytic and photocatalytic approaches have high faradaic efficiency of carbon dioxide reduction (1,6). but very low current densities. Hence the rate of product formation is low. Increasing current densities to provide meaningful amounts of product, substantially reduces carbon dioxide reduction in favor of hydrogen evolution. This reduction in current efficiency is a difficult problem to surmount in light of the probable electrostatic repulsion of carbon dioxide, or the aqueous bicarbonate ion, from a negatively charged cathode (11,12). 

Regarding suitable cathodes for the electrocatalytic reduction of carbon dioxide to methanol, indium, and tin have good prospects because each has a high overpotential for hydrogen evolution, the chief competitor in aqueous solution for carbon dioxide reduction to methanol ... 

However, Hori (1986) found the electrocatalytic reduction of carbon dioxide to methane on a molybdenum cathode to be electrocatalytic [11]. One hundred percent reduction of carbon dioxide to methanol at 0°C was reported. What remains open to research is the use of nonaqueous solvents, for example, acetonitrile, because there would be then no competition from hydrogen evolution. Carbon dioxide does undergo electrochemical reduction in acetonitrite to glycolic acid. Here is a research topic, which could have world consequences and cost very little (about 105 per year per researcher, even a dozen would make a great difference in five years). 

The importance of reactions of cobalt(I) complexes with proton donors in the context of understanding the photo- and electrocatalytic reduction of water to H2 and of carbon dioxide to HCO2 has been highlighted. [146] In a series of reports the thermodynamics and kinetics of proton binding to the cobalt(I) complex of the macrocycle, 5,7,7,12,14,14,-hexamethyl-... 

A number of transition-metal complexes, both in solution and on electrode surfaces, have been shown to be effective in the electrocatalytic reduction of carbon dioxide. All of those complexes significantly decrease the overpotential for reduction of CO2 by up to IV (as compared to a 1-el reduction to the C02 radical), and yield various multielectron reduction products. Known electrocatalysts yield primarily carbon monoxide and formate anion as the major products of the CO2 reduction. Sullivan et al. did detailed mechanistic work on a sales of bipyridine complexes of transition metals, and made several suggestions concerning the design of new electrocatalysts that would be capable of reducing CO2 past the CO and formate step. Their major recommendation is to use as electrocatalysts "electron reservoir" complexes, i.e. compounds capable of storing multiple electrons. 

K. R. Electrochemical and IR Spectroelectrochemical Studies of the Electrocatalytic Reduction of Carbon Dioxide by [Ir2(dimen)4] (dimen = 1,8-Diisocyanomenthane),/norg. Chem. 1996,35,... 

The electrocatalytic reduction of carbon dioxide has recently been reviewed [20]. Work in this area has concentrated on transition meatal complexes such as metal polypyridyl complexes [21], metal macrocycle complexes [22,23] and the use of different metals and alloys [24],... 

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