Publicação
Electrochemical production of syngas from CO2 at pressures up to 30 bar in electrolytes containing ionic liquid
| Resumo: | ABSTRACT: Electrochemical CO2 reduction in a reactor that can operate up to 100 bar and 80 degrees C, with a configuration similar to that of an alkaline electrolyser, for hydrogen production suitable to be used industrially is reported for the first time. The effect of pressure on the co-electrolysis of CO2 and water was studied. The successful scale-up from a previously reported batch process to electrodes of ca. 30 cm(2) geometrical area (30-fold factor) that combines the use of pressure and an ionic liquid-based electrolyte is presented. Also for the first time, the potential of the system under study to achieve high conversions of CO2 to avoid a purification step of syngas from unreacted CO2 is shown. An inexpensive commercial foil of the common metal zinc was employed. A semi-continuous operation yielded syngas productivities in the range of 0.02-0.04 mmol cm(-2) h(-1) at ca. -1.2 V vs. QRE Ag/Ag+. When an electrolyte consisting of 90 wt% H2O and 10 wt% 1-ethyl-3-methylimidazolium trifluoromethanesulfonate was used, selectivities for CO in the range of 62% to 72% were obtained at 10 bar pressure, whereas selectivities of 82% were obtained at 30 bar pressure. H-2/CO ratios in the range of 1/1 to 4/1 at 10 bar pressure suitable for the synthesis of a variety of fuels, such as hydrocarbons, methanol, methane and chemical building blocks, were observed. An energy efficiency of 44.6% was calculated for a H-2/CO ratio of 2.2 suitable for the synthesis of methanol. |
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| Autores principais: | Messias, Sofia |
| Outros Autores: | Sousa, Miguel M.; Ponte, Manuel Nunes; Rangel, C. M.; Pardal, T.; Machado, Ana |
| Assunto: | Carbon dioxide Electrochemical reduction Energy conversion Ionic liquids Electrolytes |
| Ano: | 2019 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Laboratório Nacional de Energia e Geologia, I.P. |
| Idioma: | inglês |
| Origem: | Repositório do LNEG |
| Resumo: | ABSTRACT: Electrochemical CO2 reduction in a reactor that can operate up to 100 bar and 80 degrees C, with a configuration similar to that of an alkaline electrolyser, for hydrogen production suitable to be used industrially is reported for the first time. The effect of pressure on the co-electrolysis of CO2 and water was studied. The successful scale-up from a previously reported batch process to electrodes of ca. 30 cm(2) geometrical area (30-fold factor) that combines the use of pressure and an ionic liquid-based electrolyte is presented. Also for the first time, the potential of the system under study to achieve high conversions of CO2 to avoid a purification step of syngas from unreacted CO2 is shown. An inexpensive commercial foil of the common metal zinc was employed. A semi-continuous operation yielded syngas productivities in the range of 0.02-0.04 mmol cm(-2) h(-1) at ca. -1.2 V vs. QRE Ag/Ag+. When an electrolyte consisting of 90 wt% H2O and 10 wt% 1-ethyl-3-methylimidazolium trifluoromethanesulfonate was used, selectivities for CO in the range of 62% to 72% were obtained at 10 bar pressure, whereas selectivities of 82% were obtained at 30 bar pressure. H-2/CO ratios in the range of 1/1 to 4/1 at 10 bar pressure suitable for the synthesis of a variety of fuels, such as hydrocarbons, methanol, methane and chemical building blocks, were observed. An energy efficiency of 44.6% was calculated for a H-2/CO ratio of 2.2 suitable for the synthesis of methanol. |
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