Bench-scale electrochemical system for generation of CO and syn-gas

A flow cell based, bench-scale electrochemical system for generation of synthesis-gas (syn-gas) is reported. Sensitivity to operating conditions such as CO2 flow, current density, and elevated temperature are described. By increasing the temperature of the cell the kinetic overpotential for the reduction of CO2 was lowered with the cathode voltage at 70 mA cm−2 decreased by 0.32 V and the overall cell voltage dropping by 1.57 V. This equates to an 18% increase in cell efficiency. By closely monitoring the products it was found that at room temperature and 70 °C the primary products are CO and H2. By controlling the current density and the flow of CO2 it was possible to control the H2:CO product ratio between 1:4 and 9:1. The reproducibility of performing experiments at elevated temperature and the ability to generate syn-gas for extended periods of time is also discussed.

[1]  Bent Sørensen,et al.  Hydrogen and Fuel Cells , 2005 .

[2]  K. Hashimoto,et al.  Carbon dioxide reduction at low temperature on various metal electrodes , 1989 .

[3]  M. W. Chase.  NIST-JANAF thermochemical tables , 1998 .

[4]  Akihiko Kudo,et al.  Electrochemical reduction of carbon dioxide under high pressure on various electrodes in an aqueous electrolyte , 1995 .

[5]  K. W. Frese,et al.  Electrochemical Reduction of Carbon Dioxide to Methane, Methanol, and CO on Ru Electrodes , 1985 .

[6]  A. Fujishima,et al.  Electrochemical Reduction of CO 2 in the Micropores of Activated Carbon Fibers , 2000 .

[7]  G. Moradi,et al.  Effects of Feed Composition and Space Velocity on Direct Synthesis of Dimethyl Ether from Syngas , 2008 .

[8]  D. Lowy,et al.  Electrochemical reduction of carbon dioxide on flat metallic cathodes , 1997 .

[9]  Toshio Tsukamoto,et al.  Electrocatalytic process of CO selectivity in electrochemical reduction of CO2 at metal electrodes in aqueous media , 1994 .

[10]  J. Morse,et al.  The carbonic acid system and calcite solubility in aqueous Na-K-Ca-Mg-Cl-SO4 solutions from 0 to 90°C , 1993 .

[11]  K. H. Tetzlaff,et al.  Alkaline falling-film fuel cell A breakthrough in technology and cost , 1994 .

[12]  Narendra K. Gupta,et al.  Electrochemical reduction of CO2 to hydrocarbons to store renewable electrical energy and upgrade biogas , 2007 .

[13]  Ronald L. Cook,et al.  High Rate Gas Phase CO 2 Reduction to Ethylene and Methane Using Gas Diffusion Electrodes , 1990 .

[14]  Devin T. Whipple.  Microfluidic reactor for the electrochemical reduction of carbon dioxide , 2010 .

[15]  John Newman,et al.  Design of an Electrochemical Cell Making Syngas ( CO + H2 ) from CO2 and H2O Reduction at Room Temperature , 2007 .

[16]  M. N. Mahmood,et al.  Use of gas-diffusion electrodes for high-rate electrochemical reduction of carbon dioxide. II. Reduction at metal phthalocyanine-impregnated electrodes , 1987 .

[17]  Yoshio Hori,et al.  Silver-coated ion exchange membrane electrode applied to electrochemical reduction of carbon dioxide , 2003 .

[18]  Ulrich Kunz,et al.  Chlor-alkali electrolysis with oxygen depolarized cathodes: history, present status and future prospects , 2008 .

[19]  Masahiro Hiramoto,et al.  Electrochemical Reduction of Carbon Dioxide on Various Metal Electrodes in Low‐Temperature Aqueous KHCO 3 Media , 1990 .

[20]  George A. Olah,et al.  Beyond Oil and Gas: The Methanol Economy , 2005 .

[21]  Akihiko Kudo,et al.  Change in the product selectivity for the electrochemical CO2 reduction by adsorption of sulfide ion on metal electrodes , 1997 .

[22]  K. Hara,et al.  Electrocatalytic Formation of CH 4 from CO 2 on a Pt Gas Diffusion Electrode , 1997 .

[23]  Hiro-o Tominaga,et al.  Selective synthesis of dimethyl ether from synthesis gas. , 1984 .