TiO₂ Nanotube Arrays Modified Titanium: A Stable, Scalable, and Cost-Effective Bioanode for Microbial Fuel Cells

Abstract

Titanium has been widely used as a dimensionally stable anode in the electrolysis industry because of its excellent corrosion resistance, conductivity, and scalability. However, because of its poor biocompatibility and poor performance as a bioanode, it has drawn little attention in the field of microbial fuel cells (MFCs). This study reports an efficient way to convert a titanium electrode into a high-performance anode for MFCs, in situ growth of titanium dioxide nanotubes (TNs) on its surface. After TN modification, the titanium surface became rougher, more hydrophilic, and more conducive for anodic biofilm formation. The maximal current density achieved on this TNmodified titanium electrode was 12.7 A m −2 , which was 190-fold higher than that of the bare titanium electrode and even higher than that of the most commonly used carbon felt electrode. Therefore, the high conductivity, corrosion resistance, and current density make the TN-modified titanium electrode a promising and scalable anode for MFCs.

Effect of surface roughness, porosity and roughened micro-pillar structures on the early formation of microbial anodes

“…which has been shown to be heavily detrimental to electroactive biofilms [46][47][48]. According to the equations developed previously, the modified Damköhler number (Da mod ) relative to HCO 3 is:…”

“…Mass transfer of the buffering species was no longer able to mitigate the acidification at the bottom of the micro-pillar array. This issue points out, once again, the crucial importance of interfacial acidification [46][47][48] and the importance of ion transport to mitigate it [56].…”

Effects of the Structure of TiO2 Nanotube Arrays on Its Catalytic Activity for Microbial Fuel Cell

“…According to the XRD results, anatase is the dominant phase in both the TNA‐HF and TNA‐NF samples. As calcination was performed at 500 °C, no rutile phase was observed . Figure b,c shows the high‐resolution X‐ray photoelectron spectroscopy (XPS) spectra of the Ti and O regions, respectively.…”

“…The measurements were conducted at a stable ambient temperature (30 ± 2 °C). The anolyte consisted of CH 3 COONa (10 × 10 −3 m ), NH 4 Cl (5 × 10 −3 m ), NaCl (30 × 10 −3 m ), MgSO 4 (8 × 10 −3 m ), and other trace elements . The anolyte was inoculated with the liquid from sludge storage which contains microorganism (in Figure S7, Supporting Information).…”

Impact of electrode micro- and nano-scale topography on the formation and performance of microbial electrodes

“…Surfaces modified with titanium oxide nanowires (Jia et al, 2016) and titanium oxide nanotubes (Feng et al, 2016) have shown that a titanium surface with a nanometre organization constitutes a suitable electrode material for forming microbial anodes, in contrast to smooth titanium, which has proved to be of no interest. After inoculation with effluent from an existing acetate-fed MFC reactor, no biofilm developed on smooth titanium, and consequently no current was produced, while the titanium electrodes coated with nanotubes were completely covered with biofilm and produced 12.7 A m -2 .…”