Ferroelectric LiTaO₃ as novel photo‐electrocatalyst in microbial fuel cells

Abstract

Microbial fuel cells (MFCs) are a promising technology for simultaneous electricity generation and wastewater treatment. Noble materials can offer high catalyst performance in MFCs but their high cost poses an obstacle for the practical implementation of this technology. Ferroelectric materials such as LiTaO 3 are a new generation of photocatalysts that could potentially be used for the oxygen reduction reaction in these devices. Thus, this work investigates the performance of LiTaO 3 as cathode catalyst in MFCs for the first time. The power performance of carbon cloth cathodes coated with LiTaO 3 was assessed in the presence and absence of light irradiation in MFC systems using wastewater. Prior to be tested in MFCs, the synthesized phase of LiTaO 3 was mainly characterized by XRD, particle-size distribution, TEM, and UV-vis spectroscopy analyses. The results show that the performance of the cathode coated with LiTaO 3 significantly improves under UV-vis irradiation, with a threefold increase in maximum power density compared with the results obtained in the absence of light source. Under these conditions, COD removal from wastewater reached 66% after 120 h.

Preparation of new ferroelectric Li0.95Ta0.57Nb0.38Cu0.15O3 materials as photocatalysts in microbial fuel cells

“…This power value is 10 times greater than that of the MFC using the photocatalyst prepared by slow cooling, displaying a higher catalytic activity. [40] Compared with previous works, the power generated in the case of the Li 0.95 Ta 0.57 Nb 0.38 Cu 0.15 O 3 prepared by rapid cooling (205 mW/m 3 ) was 3.7 fold higher than that of the LiTaO 3 (55 mW/m 3 ), [33] and 1.6 fold higher than that of the LiNbO 3 , [43] indicating an important efficiency of the photocatalyst prepared by rapid cooling. [38] The smallest particles (11.24 mm) of the photocatalyst prepared by rapid cooling could also improve the catalytic properties compared with the photocatalyst prepared by slow cooling (42.60 mm) (see the PDS analysis).…”

“…[14] These materials are known by their catalytic performance for the oxygen reduction reaction, but they are too expensive and vulnerable to contaminations by compounds present in wastewater. [2,[31][32][33]39] In this work, a new photocatalytic material with the chemical formula Li 0.95 Ta 0.57 Nb 0.38 Cu 0.15 O 3 is studied as a cathode catalyst in microbial fuel cells. [19][20][21][22][23][24] These materials mentioned above are limited by their selectivities, stabilities, and catalytic activities.…”

Photochemical Biofuel Cells

“…Another material used as photocathode is lithium-tantalate (LiTaO 3 ), which was also used as a photocathode in biological fuel cell application. When LiTaO 3 photocathode was illuminated with a 500 W of UV/Vis intensity, it can deliver 3-folds higher of power (55 mW cm −2 ) compared to that of the dark reaction (17 mW cm −2 ) [85]. Copper indium sulfide (CuInS 2 ) has also been used as photocathode in a dual-chamber PE-BFC.…”

BaTiO3 Functional Perovskite as Photocathode in Microbial Fuel Cells for Energy Production and Wastewater Treatment

“…It was reported that LiNbO 3 cathodes exhibited a maximum power of 131 mW m −3 under irradiation and a maximum chemical oxygen demand (COD) removal of 84% [ 9 ]. In another study, LiTaO 3 , a ferroelectric material, has shown good performances as a photocathode with a maximum generated power of 55 mW m −3 and a COD removal power of 66% [ 18 ]. The electrocatalytic performance of ceramic materials, such as (Li 0 .…”