Electroreduction of carbon dioxide

Ruthenium is a known active catalyst for the hydrogenation of carbon monoxide to hydrocarbons (the Fischer-Tropsch synthesis). It was shown that on rathenized electrodes, methane can form in the electroreduction of carbon dioxide as weU. At temperatures of 45 to 80°C in acidihed solutions of Na2S04 (pH 3 to 4), faradaic yields for methane formation up to 40% were reported. On a molybdenium electrode in a similar solution, a yield of 50% for methanol formation was observed, but the yield dropped sharply during electrolysis, due to progressive poisoning of the electrode. 

Scheme 127 Catalytic cycle for the electroreduction of carbon dioxide to carbon monoxide and formate.

The Electroreduction of Carbon Dioxide in Protic Media (Water and Alcohols) 327... 

According to the last mechanism an electrochemical active particle is carbon dioxide. Therefore direct electroreduction of carbon dioxide, dissolved in the salt melts must also give a carbon as a cathode product. It was confirmed in the [6, 7], but there were no any data about morphology and structure of obtained carbon powders. The electrodeposition of carbon from carbon dioxide was taken as the base process for high-temperature electrochemical synthesis (HTES) of refractory carbides [8, 9]. 

Electroreduction of carbon dioxide up to carbon can be taken as the base of high-temperature electrochemical synthesis (HTES) of various nano-sized carboniferous inorganic compounds carbon films and powders of different structures. 

The different electrocatalytic reactions described below concern the oxidation of molecular hydrogen and of small organic molecules and alcohols, the reduction of protons and of dioxygen, the electrohydrogenation of organic molecules, the reduction of halides and the electroreduction of carbon dioxide. 

Figure 5.17. Relevant part of Pc s and the antibonding MO and CO2. Reprinted from Figure 5.2 N. Furuya and S. Koide, Electroreduction of carbon dioxide by metal phthalo-cyanines, Electrochimica Acta, 36(8), 1309-1313 (1991). Copyright 1991, with permission of Elsevier.

Abbi, F., G. de Santis, L. Fabbrizzi, M. Licchelli, A.M.R Manotti-Lanfredi, R Rallavicini, A. Roggi, F. Ugozzoliz (1994). Nickel(II) complexes of azacyclams oxidation and reduction behavior and catalytic effects in the electroreduction of carbon dioxide. Inorg. Chem. 33, 1366-1375. 

Furuya, N. and K. Matsui (1989). Electroreduction of carbon dioxide on gas-diffusion electrodes modified by metal phthalocyanines. J. Electroanal. Chem. 271(1-2), 181-191. 

Aga, H., A. Aramata, and Y. Hisaeda (1997). The electroreduction of carbon dioxide by macrocyclic cobalt complexes chemically modified on a glassy carbon electrode. 

Vassiliev YB, Bagotzky VS, Osetrova NV, Khazova OA, Mayorova NA (1985) Electroreduction of carbon-dioxide 1. The mechanism and kinetics of electroreduction Of CO2 in aqueous-solutions on metals with high and moderate hydrogen overvoltages. J Electroanal Qiem 189(2) 271-294... 

Peterson AA, Abild-Pedersen F, Studt F, Rossmeisl J, Nprskov JK (2010) How copper catalyzes the electroreduction of carbon dioxide into hydrocarbon fuels. Energy Environ Sci 3 1311-1315... 

Nikolic, B.Z., et al. 1990. Electroreduction of carbon dioxide on platinum single crystal electrodes electrochemical and in situ FT-IR studies. /. Electroanal. Chem. 295 415-423. 

Tin dioxide, an n-type semiconductor with a wide bandgap (3.6 eV at 300 K), has been widely studied as a sensor, a (photo)electrode material and in oxidation reactions for depollution. The performance of tin(iv) oxide is closely linked to structural features, such as nanosized crystallites, surface-to-volume ratio and surface electronic properties. The incentive for carbon-dioxide transformation into value-added products led to examination of the electroreduction of carbon dioxide at different cathodes. It has been recognised that the faradic yield and selectivity to carbon monoxide, methane, methanol, and formic acid rely upon the nature of the cathode and pH. ° Tin(iv) oxide, as cathode, was found to be selective in formate formation at pH = 10.2 with a faradic yield of 67%, whereas copper is selective for methane and ethene, and gold and silver for carbon monoxide. Nano-tin(iv) oxide has been shown to be active and selective in the carboigrlation of methanol to dimethyl carbonate at 150 °C and 20 MPa pressure. The catalyst was recyclable and its activity and selectivity compare with that of soluble organotins (see Section 21.5). 

Tezuka M, Yajima T, Tsuchiya A, Matsumoto Y, Uchida Y, Hidai M (1982) Electroreduction of carbon dioxide catalyzed by iron-sulfur cluster compounds [Fe4S4(SR)4] . J Am (Them Soc 104 6834-6836... 

Christophe J, Doneux T, Buess-Herman C (2012) Electroreduction of carbon dioxide on copper-based electrodes activity of copper single crystals and copper-alloys. Electrocatalysis 3 139-146... 

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