title: Spontaneous modification of graphite anode by anthraquinone-2-sulfonic acid for microbial fuel cells.
abstract: In this study, anthraquinone-2-sulfonic acid (AQS), an electron transfer mediator, was immobilized onto graphite felt surface via spontaneous reduction of the in situ generated AQS diazonium cations. Cyclic voltammetry (CV) and energy dispersive spectrometry (EDS) characterizations of AQS modified graphite demonstrated that AQS was covalently grafted onto the graphite surface. The modified graphite, with a surface AQS concentration of 5.37 ± 1.15 × 10(-9)mol/cm(2), exhibited good electrochemical activity and high stability. The midpoint potential of the modified graphite was about -0.248 V (vs. normal hydrogen electrode, NHE), indicating that electrons could be easily transferred from NADH in bacteria to the electrode. AQS modified anode in MFCs increased the maximum power density from 967 ± 33 mW/m(2) to 1872 ± 42 mW/m(2). These results demonstrated that covalently modified AQS functioned as an electron transfer mediator to facilitate extracellular electron transfer from bacteria to electrode and significantly enhanced the power production in MFCs.
authors.affiliation: National University of Singapore, Department of Civil and Environmental Engineering, Centre for Water Research, Singapore 117576, Singapore; National University of Singapore, NUS Graduate School for Integrative Sciences and Engineering, Singapore 117456, Singapore.
authors.forename: Xinhua
authors.initials: X
authors.lastname: Tang
authors.affiliation: Chinese Academy of Sciences, Institute of Process Engineering, National Key Laboratory of Biochemical Engineering, Beijing 100190, China.
authors.forename: Haoran
authors.initials: H
authors.lastname: Li
authors.affiliation: Chinese Academy of Sciences, Institute of Process Engineering, National Key Laboratory of Biochemical Engineering, Beijing 100190, China.
authors.forename: Zhuwei
authors.initials: Z
authors.lastname: Du
authors.affiliation: National University of Singapore, Department of Civil and Environmental Engineering, Centre for Water Research, Singapore 117576, Singapore. Electronic address: howyongng@nus.edu.sg.
authors.forename: How Yong
authors.initials: HY
authors.lastname: Ng
mesh_terms: D000880:Anthraquinones / Q000737:chemistry*; D001674:Bioelectric Energy Sources; D004560:Electricity; D055664:Electrochemical Techniques; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission
chemical_list: D000880:Anthraquinones; C023554:anthraquinone sulfonate; D006108:Graphite
keywords: Anodic electron transfer; Anthraquinone-2-sulfonic acid; Diazonium cations; Graphite anode; Microbial fuel cells