Hierarchical N-doped C/Fe3O4 nanotube composite arrays grown on the carbon fiber cloth as a bioanode for high-performance bioelectrochemical system

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 406; p. 126832
• Main Authors: Wang, Yi, Liu, Chuangchuang, Zhou, Shaofeng, Hou, Rui, Zhou, Lihua, Guan, Fengyi, Chen, Renlian, Yuan, Yong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.02.2021
• Subjects: Bioelectrochemical systems; Bioelectrode; Current output; N-doped carbon; Nanotube arrays; Nanotube arrays; N-doped carbon; Bioelectrode; Current output; Bioelectrochemical systems
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2020.126832

[Display omitted] •The CC@N-C/Fe3O4 electrode was fabricated from N-doped C/Fe3O4 nanotube arrays on CC.•CC@N-C/Fe3O4 exhibited high conductivity, capacitance and low Rct for EET.•The CC@N-C/Fe3O4 nano-structure supports microbial adhesion and substrate diffusion.•CC@N-C/Fe3O4 achieved high current output (4.11 mA/cm2) and CE (89%) in BES.•CC@N-C/Fe3O4 could serve as a potential 3D electrode for high-performance BES. Three-dimensional (3D) nano-structure materials with a large bacterial accessible specific area have emerged as promising electrode materials for bioelectrochemical systems (BESs), achieving high bioelectricity outputs. However, it remains a challenge that biofilms with increased thickness inhibit substrate diffusion into the 3D nano-structure during long-term operation of BESs, causing a reduction in bioenergy output. Herein, an innovative ordered 3D nano-structure electrode was fabricated by growing self-supported N-doped C/Fe3O4-nanotube composite arrays onto carbon fiber cloth (CC@N-C/Fe3O4), using template-based deposition coupled with thermal reduction/carbonization methods. The fabricated CC@N-C/Fe3O4 electrode was applied as a bioelectrode in a conventional three-electrode BES and as an anode in microbial fuel cell (MFC), while their capacity to improve bioelectricity generation was assessed. Results indicate that the hierarchical N-doped C-coated nanotube arrays not only significantly enhanced conductivity and areal capacitance of the electrode, but also reduced its charge transfer resistance and provided the 3D open nano-structure with excellent biocompatibility for microbial colonization and internal diffusion of the culture substrate. Consequently, a high maximum current density (4.11 mA/cm2) and coulombic efficiency (~89%) was obtained from the CC@N-C/Fe3O4 electrode after about 3 months of BES operation, exhibiting higher biocatalytic performance and extracellular electron transfer efficiency than the original carbon fiber cloth (CC, 1.89 mA/cm2). Moreover, MFC equipped with CC@N-C/Fe3O4 anode produced a maximum power density of 1.21 ± 0.04 W/m2, which was 2.1 times higher than CC (0.58 ± 0.03 W/m2). This study demonstrates the outstanding advantages of CC@N-C/Fe3O4 nanotube composite arrays assembled on CC, making it a potential alternative to existing 3D electrodes for high-performance BES applications.