title: Conduction-band edge dependence of carbon-coated hematite stimulated extracellular electron transfer of Shewanella oneidensis in bioelectrochemical systems.
abstract: Bacteria-based bioelectrochemical systems (BESs) are promising technologies used for alternative energy generation, wastewater treatment, and environmental monitoring. However, their practical application is limited by the bioelectrode performance, mainly resulting from low extracellular electron transfer (EET) efficiency. In this study, a carbon-coated hematite (C/Hematite) electrode was successfully obtained by a green and solvent-free route, that is, heat treatment in an oxygen-rich environment using solid ferrocene as the precursor. The as-prepared C/Hematite electrode was evaluated as a high-performance electrode material in a Shewanella oneidensis-inoculated BES. The maximum biocurrent density of the Shewanella-attached C/Hematite electrode reached 0.22 ± 0.01 mA cm(-2), which is nearly 6-times higher than that of a bare carbon cloth (CC) electrode (0.036 ± 0.005 mA cm(-2)). Electrochemical measurements revealed that the enhanced conductivity and better energy matching between the outer membrane c-type cytochromes of S. oneidensis and the electrode contributed to the improved EET efficiency. The results of this study demonstrated that the semiconductive properties of iron oxides play important roles for the involved bacterial extracellular respiration activities.
authors.affiliation: Guangdong Institute of Eco-environmental and Soil Sciences, 808 Tianyuan Road, Guangzhou City, Guangdong Province, PR China.
authors.forename: Shungui
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Guangdong Institute of Eco-environmental and Soil Sciences, 808 Tianyuan Road, Guangzhou City, Guangdong Province, PR China.
authors.forename: Jiahuan
authors.initials: J
authors.lastname: Tang
authors.affiliation: Guangdong Institute of Eco-environmental and Soil Sciences, 808 Tianyuan Road, Guangzhou City, Guangdong Province, PR China. Electronic address: yuanyong@soil.gd.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yuan
mesh_terms: D001674:Bioelectric Energy Sources / Q000382:microbiology*; D002244:Carbon / Q000737:chemistry*; D004553:Electric Conductivity; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport / Q000187:drug effects; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism*; D005290:Ferric Compounds / Q000737:chemistry* / Q000494:pharmacology*; D005296:Ferrous Compounds / Q000737:chemistry; D000075163:Metallocenes; D011312:Pressure; D020592:Shewanella / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
chemical_list: D005290:Ferric Compounds; D005296:Ferrous Compounds; D000075163:Metallocenes; C000499:ferric oxide; D002244:Carbon; C004998:ferrocene
keywords: Bioelectrochemical system; Carbon-coated hematite; Conduction-band edge; Extracellular electron transfer; Semiconductor