Premium
Enhanced Bio‐Electrochemical Reduction of Carbon Dioxide by Using Neutral Red as a Redox Mediator
Author(s) -
Seelajaroen Hathaichanok,
Haberbauer Marianne,
Hemmelmair Christine,
Aljabour Abdalaziz,
Dumitru Liviu Mihai,
Hassel Achim Walter,
Sariciftci Niyazi Serdar
Publication year - 2019
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201800784
Subject(s) - formate , redox , electrolysis , chemistry , electrochemistry , faraday efficiency , glassy carbon , inorganic chemistry , dielectric spectroscopy , electrode , carbon dioxide , cyclic voltammetry , organic chemistry , catalysis , electrolyte
Microbial electrosynthetic cells containing Methylobacterium extorquens were studied for the reduction of CO 2 to formate by direct electron injection and redox mediator‐assisted approaches, with CO 2 as the sole carbon source. The formation of a biofilm on a carbon felt (CF) electrode was achieved while applying a constant potential of −0.75 V versus Ag/AgCl under CO 2 ‐saturated conditions. During the biofilm growth period, continuous H 2 evolution was observed. The long‐term performance for CO 2 reduction of the biofilm with and without neutral red as a redox mediator was studied by an applied potential of −0.75 V versus Ag/AgCl. The neutral red was introduced into the systems in two different ways: homogeneous (dissolved in solution) and heterogeneous (electropolymerized onto the working electrode). The heterogeneous approach was investigated in the microbial system, for the first time, where the CF working electrode was coated with poly(neutral red) by the oxidative electropolymerization thereof. The formation of poly(neutral red) was characterized by spectroscopic techniques. During long‐term electrolysis up to 17 weeks, the formation of formate was observed continuously with an average Faradaic efficiency of 4 %. With the contribution of neutral red, higher formate accumulation was observed. Moreover, the microbial electrosynthetic cell was characterized by means of electrochemical impedance spectroscopy to obtain more information on the CO 2 reduction mechanism.