Highly Conductive Poly(3,4-ethylenedioxythiophene) Polystyrene Sulfonate Polymer Coated Cathode for the Microbial Electrosynthesis of Acetate From Carbon Dioxide

Abstract

Microbial electrosynthesis (MES) is a bioelectrochemical technology developed for the conversion of carbon dioxide and electric energy into multicarbon chemicals of interest. As with other biotechnologies, achieving high production rate is a prerequisite for scaling up. In this study, we report the development of a novel cathode for MES, which was fabricated by coating carbon cloth with conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) polymer. Sporomusa ovata-driven MES reactors equipped with PEDOT:PSS-carbon cloth cathodes produced 252.5 ± 23.6 mmol d −1 acetate per m 2 of electrode over a period of 14 days, which was 9.3 fold higher than the production rate observed with uncoated carbon cloth cathodes. Concomitantly, current density was increased to −3.2 ± 0.8 A m −2 , which was 10.7-fold higher than the untreated cathode. The coulombic efficiency with the PEDOT: PSS-carbon cloth cathodes was 78.6 ± 5.6%. Confocal laser scanning microscopy and scanning electron microscopy showed denser bacterial population on the PEDOT:PSS-carbon cloth cathodes. This suggested that PEDOT:PSS is more suitable for colonization by S. ovata during the bioelectrochemical process. The results demonstrated that PEDOT: PSS is a promising cathode material for MES.

Increased carbon dioxide reduction to acetate in a microbial electrosynthesis reactor with a reduced graphene oxide-coated copper foam composite cathode

“…In recent years, research efforts have been carried out to increase the productivity of MES systems for potential scaling up. Microbial catalysts, growth medium, and cathodes are all components of MES reactors that have been studied and optimized [9][10][11][12][13][14][15][16][17][18]. Electron transfer from the cathode to microbes is at the core of MES and multiple strategies have pursued the development of novel electrode materials and spatial arrangements to improve it.…”

Accelerated H2 Evolution during Microbial Electrosynthesis with Sporomusa ovata

“…To study the possible correlation between microbial alterations and H 2 evolution in a MES system, a hydrogen microsensor was placed in close proximity to the surface of a cathode set at different potentials to measure H 2 evolution in situ in the presence of sterile medium, bacterial culture or cell-free filtrate. Sporomusa ovata, one of the best pure culture MES catalysts for the production of acetate from CO 2 [38,39] is used here as a model because of its capacity to perform MES over a large range of cathode potential [3,[40][41][42][43][44][45][46]. In order to further understand H 2 evolution and electron uptake during MES, other variables were investigated, including the presence of metals at the cathode surface as well as the presence of hydrogenases and other enzymes in the cell-free spent medium.…”

Sporomusa ovata as Catalyst for Bioelectrochemical Carbon Dioxide Reduction: A Review Across Disciplines From Microbiology to Process Engineering

“…Sporomusa ovata grown on cathodes use the electrode as an electron source and CO 2 as the carbon source to sustain their autotrophic metabolism. We found that pre-cultures for bioelectrochemical experiments are also grown autotrophically under H 2 and CO 2 conditions ( Aryal et al, 2016 , 2017b , 2018 , 2019 ; Chen et al, 2016 ). We have not found any published study inoculating bioelectrochemical experiments directly from a betaine grown S. ovata culture.…”

“… Acetate production rates of S. ovata with different electrode materials. Bars of the same color are derived from the same studies: [1]: ( Aryal et al, 2019 ), [2]: ( Aryal et al, 2016 ), [3]: ( Bian et al, 2018 ), [4]: ( Li et al, 2018 ), [5]: ( Cui et al, 2017 ), [6]: ( Aryal et al, 2017a ), [7]: ( Aryal et al, 2018 ), [8]: ( Aryal et al, 2016 ), [9]: ( Gong et al, 2013 ), [10]: ( Zhang et al, 2013 ). On that basis, the same color results are directly comparable, as other parameters (cathode potential, medium, temperature, reference for normalization) are equal.…”