Comparison of nonprecious metal cathode materials for methane production by electromethanogenesis

Michael Siegert, Matthew D. Yates, Douglas F. Call, Xiuping Zhu, Alfred Spormann, Bruce E. Logan

Research output: Contribution to journalArticle

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Abstract

In methanogenic microbial electrolysis cells (MMCs), CO 2 is reduced to methane using a methanogenic biofilm on the cathode by either direct electron transfer or evolved hydrogen. To optimize methane generation, we examined several cathode materials: plain graphite blocks, graphite blocks coated with carbon black or carbon black containing metals (platinum, stainless steel or nickel) or insoluble minerals (ferrihydrite, magnetite, iron sulfide, or molybdenum disulfide), and carbon fiber brushes. Assuming a stoichiometric ratio of hydrogen (abiotic):methane (biotic) of 4:1, methane production with platinum could be explained solely by hydrogen production. For most other materials, however, abiotic hydrogen production rates were insufficient to explain methane production. At -600 mV, platinum on carbon black had the highest abiotic hydrogen gas formation rate (1600 ± 200 nmol cm -3 d -1 ) and the highest biotic methane production rate (250 ± 90 nmol cm -3 d -1 ). At -550 mV, plain graphite (76 nmol cm -3 d -1 ) performed similarly to platinum (73 nmol cm -3 d -1 ). Coulombic recoveries, based on the measured current and evolved gas, were initially greater than 100% for all materials except platinum, suggesting that cathodic corrosion also contributed to electromethanogenic gas production.

Original languageEnglish (US)
Pages (from-to)910-917
Number of pages8
JournalACS Sustainable Chemistry and Engineering
Volume2
Issue number4
DOIs
StatePublished - Apr 7 2014

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

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