Photocoupled Bioanode: A New Approach for Improved Microbial Fuel Cell Performance

Abstract

Microbial fuel cells (MFCs) received considerable attention because of their ability to provide dual advantages of electricity generation and wastewater treatment. However, their performance is primarily limited by the slow oxygen reduction reaction (ORR). To alleviate this problem, we describe a hybrid MFC in which a conventional bioanode is coupled with a TiO2 photoanode. The photocatalytic photoanode utilizes light to provide additional photogenerated electrons to the external circuit of the MFC, which promotes the ORR, as confirmed by power density curves and electrochemical impedance spectra, resulting in improved power generation (1284±20 mW m−2) compared to that of a normal MFC (850±12 mW m−2). Furthermore, the ability of the TiO2 photoanode to reduce CO2 to methane is demonstrated.

Improved Microbial Electrolysis Cell Hydrogen Production by Hybridization with a TiO2 Nanotube Array Photoanode

“…1D nanostructure TiO 2 such as nanotube has crucial advantages over other nanostructures, because we can control its physical properties, specifically diameter and length, which results in an improved and effective system [60]. In a previous study on a MFC coupled with an external TNT array photoanode, we confirmed that supplementary electrons accelerate the oxygen reduction reaction at air cathode, improving overall MFC performance [20].…”

“…The anodization electrolyte was ethylene glycol with 0.5 wt.% NH 4 F and 2.0 vol.% DI water. Anodization was performed at 40 V for 30 min, as previously reported [20,61]. With anodization, Ti 4+ ions are generated (Ti → Ti 4+ + 4e − ) and driven from Ti substrate to the electrolyte by electric field.…”

“…The electrons flow through the electrical circuit to reach the air cathode, where they react with atmospheric oxygen and protons to produce water through the oxygen reduction reaction [13,14]. To improve MFC performance, recent studies have investigated the combination of MFCs with external photocurrent sources, such as photosynthetic microorganisms [15,16], a copper oxide photocathode [17], a PtO x -TiO 2 composite photocathode [18], a CuInS 2 photocathode [19], or a TiO 2 nanotube (TNT) array photoanode [20].…”

Rational design of artificial redox-mediating systems toward upgrading photobioelectrocatalysis

“…There has been a relatively recent surge in biohybrids of non-photosynthetic biofilms and abiotic photosensitizers in photobioelectrocatalysis in order to generate photocurrent, recycle pollutants, and/or produce energy rich chemicals [112][113][114][115][116]. These biohybrids constitute inorganic semiconductors such as TiO 2 [117][118][119], CdS [120][121][122], Rutile [123], Hematite [112,113], CuInS 2 [124], α-Fe 2 O 3 [114] and organic dyes such as Eosin Y [125] in the photosensitizer capacity, paired to bacteria such as S. oneidensis, T. denitrificans, E. coli, M. barkeri. While such systems bear the advantage of tunability (e.g., the ability to synthetically tune the bandgap of a semiconductor to facilitate the maximum solar absorbance [126]), they are nevertheless limited by poor electric wiring to the biofilms, which in turn can be overcome by redox mediation.…”

Recent Advances in Quantum Dots for Photocatalytic CO2 Reduction: A Mini-Review

“…In the present era, CO 2 has been captured (Ibrahim et al, 2018;Fu et al, 2019;Omodolor et al, 2020;Dhoke et al, 2021;Lau et al, 2021), converted (Fu et al, 2019;Omodolor et al, 2020) and stored (Lau et al, 2021) by using different technologies. There are many methods and techniques that are studied for the conversion of CO 2 into renewable energy sources; among them, photocatalytic CO 2 reduction (CO 2 R) (Sorcar et al, 2018;Sorcar et al, 2019;Albero et al, 2020;Li et al, 2021), electrochemical CO 2 R (Jia et al, 2019;Liang et al, 2020), photo-biochemical CO 2 R (Kim et al, 2018), photoelectrochemical CO 2 R (Roy et al, 2016), and thermochemical CO 2 R (Maiti et al, 2018;Pullar et al, 2019) are well-known (He and Janáky, 2020). The photocatalysis process promotes the conversion reactions using clean solar energy, which is an eco-friendly CO 2 conversion technology (shown in Figure 1A).…”