Flow Electrochemistry Enables Microbial Atmospheric CO₂ Fixation via Coupling with Iodine-Mediated Organic Reactions

Abstract

Electroreduction of CO 2 powered by renewable energy has been proposed to realize carbon neutrality as a response to subsequent global warming. However, these strategies either suffer from low efficiency and spatial and temporal limitations or require a large amount of energy and CO 2 gas of high purity. These shortcomings can be addressed by the development of a green, renewable electrochemical system that directly fixes atmospheric CO 2 to generate biomass chemicals. Here, we present a flow electrochemical microbial CO 2 fixation system (EMCF) based on the propagation of Acidithiobacillus ferrooxidans in the presence of Fe 2+ /Fe 3+ as redox mediators. We demonstrate that the overpotential is significantly reduced by the in situformed Fe 2 CoSe 4 electrocatalysts, which results in an energy consumption of 15.6 GJ per ton fixed CO 2 when paired with the oxygen evolution reaction. We show that the energy consumption can be reduced to 0.62 GJ/t when KI is used for selective 5hydroxymethylfurfural oxidation and can even supply an energy of 10.08 GJ/t at low current density. This study demonstrates that the proposed EMCF system has the potential to be a sustainable and carbon-negative platform that can convert atmospheric CO 2 into value-added biomass chemicals and realize the selective oxidation of a broad range of chemicals simultaneously.

Accelerating the dissolution kinetics of iodine with a cosolvent for a high-current zinc–iodine flow battery

“…30,31 We also expect the insights to benet the efforts of using the I 2 /I À redox for owelectrochemical synthesis 32 and CO 2 xation. 33 Author contributions…”

Selective Electrochemical Oxidation of p-Xylylene Glycol Coupled with the Hydrogen Evolution Reaction via a Continuous Flow Strategy

“…The direct electro-oxidation strategy has been well studied and usually needs to be performed using a constant voltage method to prevent the overoxidation of aldehyde. − In comparison to the direct electro-oxidation strategy, the selective oxidation of alcohol could be realized by selecting suitable redox mediators in the indirect electrosynthesis where the redox mediator is oxidized at a large current density to avoid alcohol overoxidation. − Particularly, I – /I 3 – was used as a redox mediator to attain high selectivity of the product in the indirect electro-oxidation of organics due to its inherent properties of low toxicity, electrophilicity, and easy handling. Pairing the organic oxidation of alcohol with HER in the flow system through the mediator I – /I 3 – could achieve valuable product synthesis and hydrogen production simultaneously at a higher current. − For example, our group reported efficient electro-oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) with >99% selectivity via mediators of I – /I 3 – and 2,2,6,6-tetramethylpiperidoxyl (TEMPO). However, the product yield dramatically decreased without the TEMPO mediator, which increased the cost and complicated the separation process.…”

A prototype of high-performance two-electron non-aqueous organic redox flow battery operated at −40 °C

“…1,2 Secondary batteries that store energy in solid electrodes (e.g., lithium-ion batteries) or in active species dissolved in electrolytes (e.g., redox ow batteries) can be used to supply controllable and consistent electricity to the electrical grid. [3][4][5] The essential performance of these batteries for the application under consideration means sensitivity to temperature must be addressed. [6][7][8][9][10] Redox ow batteries (RFBs) which can be operated under subzero temperature are signicant for applications in cold regions.…”