Published October 22, 2021 | Version Published
Journal article Open

Mimicking the microbial oxidation of elemental sulfur with a biphasic electrochemical cell

  • 1. Departamento De Química, Facultad De Ciencias, Universidad Nacional De Colombia, Cra 30 # 45-03, Edificio 451, Bogotá, Colombia
  • 2. The Bernal Institute and Department of Chemical Sciences, School of Natural Sciences, University of Limerick (UL), Limerick V94 T9PX, Ireland
  • 3. Instituto de Electroquímica, Universidad de Alicante, Ap.99, E–03080, Alicante, Spain

Description

The lack of an artificial system that mimics elemental sulfur (S8) oxidation by microorganisms inhibits a deep mechanistic understanding of the sulfur cycle in the biosphere and the metabolism of sulfur-oxidising microorganisms. In this article, we present a biphasic system that mimics biochemical sulfur oxidation under ambient conditions using a liquid|liquid (L|L) electrochemical cell and gold nanoparticles (AuNPs) as an interfacial catalyst. The interface between two solvents of very different polarity is an ideal environment to oxidise S8, overcoming the incompatible solubilities of the hydrophobic reactants (O2 and S8) and hydrophilic products (H+, SO32–, SO42–, etc.). Furthermore, the interfacial AuNPs provide a catalytic surface onto which O2 and S8 can adsorb. Control over the driving force for the reaction is provided by polarising the L|L interface externally and tuning the Fermi level of the interfacial AuNPs by the adsorption of aqueous anions. Comparison of electrochemical measurements using a 4-electrode closed bipolar electrochemical cell and a L|L electrochemical cell confirmed that electron transfer reactions are possible between O2, gold and S8 in biphasic systems.

Notes

M.F.S.-H. acknowledges the "Universidad Nacional de Colombia" for allowing his sabbatical leave and the "Fundación Banco de la República" through the grant 4.562.

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Additional details

Funding

Designing Reactive Functionalised Soft Interfaces _ Self-healing soft materials for solar energy conversion, energy storage, and sustainable low cost hydrogen production 13/SIRG/2137
Science Foundation Ireland
SOFT-PHOTOCONVERSION – Solar Energy Conversion without Solid State Architectures: Pushing the Boundaries of Photoconversion Efficiencies at Self-healing Photosensitiser Functionalised Soft Interfaces 716792
European Commission