Importance

Facilitating electrochemical reactions on heterogeneous surfaces is essential for achieving sustainability through the production of renewable electricity from fuels and chemicals. With previous efforts focused on the electroconversion of small molecules (e.g., H2O and CO2), advances involving complex, abundant, and high-value molecules, such as compounds derived from biomass, have been limited. This work proposes an electrochemical method, called potential cycling, which allows standard Pt nanoparticles to exhibit high activity for the electrooxidation of polyols derived from biomass. The turnover is improved by orders of magnitude, overcoming the severe limitation of negligible activity exhibited by the same catalyst under typical electrochemical conditions. In addition, the demonstration of a two-electrode system that couples the electrooxidation of the polyol with the reduction of water to H2 highlights the potential applicability of the method.

Abstract

The electrification of chemical reactions is crucial to fundamentally transform our society, which is still heavily dependent on fossil resources and unsustainable practices. In addition, electrochemical-based approaches offer a unique way to catalyze reactions through the rapid and continuous alteration of applied potentials, unlike traditional thermal processes. Here, we show how the continuous cyclic application of the electrode potential allows Pt nanoparticles to electro-oxidize biomass-derived polyols with an orders of magnitude improved turnover frequency compared to usual rates under normal conditions. of fixed potential. In addition, secondary alcohol oxidation is enhanced, with a ketosis / aldose ratio increased up to six times. The idea resulted in the construction of a symmetrical single compartment system in a two electrode configuration. Its operation by voltage cycling demonstrates high-rate electrolysis of sorbitol with formation of H2 as a desired co-product at operating voltages below 1.4 V. The designed method presents a potential approach to the use of renewable electricity to drive chemical processes.

Footnotes

    • Accepted September 2, 2021.
  • Author contributions: research designed by DK and MC; DK has done research; CZ and MZ provided new reagents / analytical tools; DK analyzed the data; and DK and MC wrote the paper.

  • The authors declare no competing interests.

  • This article is a direct PNAS submission.

  • This article contains additional information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2113382118/-/DCSupplemental.

Data availability

All study data is included in the article and / or SI Annex.


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