Application of gas diffusion electrodes in bioelectrochemical syntheses and energy conversion

Abstract

Combining the advantages of biological components (e.g., reaction specificity, self-replication) and electrochemical techniques in bioelectrochemical systems offers the opportunity to develop novel efficient and sustainable processes for the production of a number of valuable products. The choice of electrode material has a great impact on the performance of bioelectrochemical systems. In addition to the redox process at the electrodes, interactions of biocatalysts with electrodes (e.g., enzyme denaturation or biofouling) need to be considered. In recent years, gas diffusion electrodes (GDEs) have proved to be very attractive electrodes for bioelectrochemical purposes. GDEs are porous electrodes, that posses a large three-phase boundary surface. At this interface, a solid catalyst supports the electrochemical reaction between gaseous and liquid phase. This mini-review discusses the application of GDEs in microbial and enzymatic fuel cells, for microbial electrolysis, in biosensors and for electroenzymatic synthesis reactions.

Gas diffusion electrodes improve hydrogen gas mass transfer for a hydrogen oxidizing bioanode

“…Application of GDEs in combination with microorganisms is already well established for oxygen reducing cathodes. 13 Overall, the aim of this study was to improve mass transfer of hydrogen gas to a bioanode by the use of a gas diffusion electrode to increase the current density produced from this hydrogen gas. To test its suitability, we analyzed the performance of a GDE for use as a hydrogen-fed bioanode using polarization tests.…”

Studies into design and operation of microbial fuel cells using oxygen gas diffusion electrodes

“…GDEs are mounted to face one side of the electrode towards the electrolyte and the other side towards the gas phase. Usually, GDEs are used in nonbiological alkaline and proton exchange membrane fuel cells (Horst et al, 2016). Up to now, GDEs have predominantly been applied in processes such as fuel cell and chloralkali electrolysis (Bulan et al, 2011).…”

“…GDEs have advantages especially if a component from the gas phase is involved in the electrochemical reaction or when a desired gaseous component is developed at the electrode. GDEs are porous electrodes; the electrolyte can float from one side and the desired gas can diffuse into the electrode from the other side (Horst et al, 2016). The structure of the GDE represents a large threephase boundary surface between solid catalysts, electrolyte and gas phase (Horst et al, 2016).…”

“…GDEs are porous electrodes; the electrolyte can float from one side and the desired gas can diffuse into the electrode from the other side (Horst et al, 2016). The structure of the GDE represents a large threephase boundary surface between solid catalysts, electrolyte and gas phase (Horst et al, 2016). A solid catalyst at this interface supports the electrochemical reaction between gaseous and liquid phase (Horst et al, 2016).…”

Bioelectrochemical metal recovery with microbial fuel cells

“…GDEs rely on the gas molecules to react directly at the electrode surface while the produced ions are released into the electrolyte. Their use for oxygen reducing cathodes is well established 89 . The main advantage of GDEs is that the fuel for the electrode reactions (hydrogen or oxygen gas) does not need to be dissolved into the electrolyte and can, therefore, be transferred faster to the electrode.…”