Modification of electrode surface with carboxylic acid terminated alkanethiol self-assembled monolayers （SAMs） has been found to be an effective approach to improve the extracellular electron transfer （EET） of ele...Modification of electrode surface with carboxylic acid terminated alkanethiol self-assembled monolayers （SAMs） has been found to be an effective approach to improve the extracellular electron transfer （EET） of electrochemically active bacteria （EAB） on electrode surface, but the underlying mechanism behind such enhanced EET remains unclear. In this work, the gold electrodes modified by mercapto-acetic acid and mercapto- ethylamine （Au-COOH, Au-NH2） were used as anodes in microbial electrolysis cells （MECs） inoculated with Geobacter sulfurreducens DL- 1, and their electrochemical performance and the bacteria-electrode interactions were investigated. Results showed that the Fe（CN）6^3-/4^- redox reaction occurred on the Au-NH2 with a higher rate and a lower resistance than that on the Au or the Au-COOH. Both the MECs with the Au-COOH and Au-NH2 anodes exhibited a higher current density than that with a bare Au anode. The biofilm formed on the Au-COOH was denser than that on bare Au, while the biofilm on the Au-NH2 had a greater thickness, suggesting a critical role of direct EET in this system. This work suggests that functional groups such as --COOH and-NH2 could promote electrode performance by accelerating the direct EET of EAB on electrode surface.展开更多
基金The authors wish to thank the National Natural Science Foundation of China （Grant No. 21477120）, the Program for Changjiang Scholars and Innovative Research Team in University and the Collaborative Innovation Center of Suzhou Nano Science and Technology of Ministry of Education of China for the partial support of this work.
文摘Modification of electrode surface with carboxylic acid terminated alkanethiol self-assembled monolayers （SAMs） has been found to be an effective approach to improve the extracellular electron transfer （EET） of electrochemically active bacteria （EAB） on electrode surface, but the underlying mechanism behind such enhanced EET remains unclear. In this work, the gold electrodes modified by mercapto-acetic acid and mercapto- ethylamine （Au-COOH, Au-NH2） were used as anodes in microbial electrolysis cells （MECs） inoculated with Geobacter sulfurreducens DL- 1, and their electrochemical performance and the bacteria-electrode interactions were investigated. Results showed that the Fe（CN）6^3-/4^- redox reaction occurred on the Au-NH2 with a higher rate and a lower resistance than that on the Au or the Au-COOH. Both the MECs with the Au-COOH and Au-NH2 anodes exhibited a higher current density than that with a bare Au anode. The biofilm formed on the Au-COOH was denser than that on bare Au, while the biofilm on the Au-NH2 had a greater thickness, suggesting a critical role of direct EET in this system. This work suggests that functional groups such as --COOH and-NH2 could promote electrode performance by accelerating the direct EET of EAB on electrode surface.
