CO<sub>2</sub>/carbonate-mediated electrochemical water oxidation to hydrogen peroxide.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35562346.
- Also identified by DOI 10.1038/s41467-022-30251-5 and PMC identifier 9106728.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Electrochemical water oxidation reaction (WOR) to hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) via a 2e<sup>-</sup> pathway provides a sustainable H<sub>2</sub>O<sub>2</sub> synthetic route, but is challenged by the traditional 4e<sup>-</sup> counterpart of oxygen evolution. Here we report a CO<sub>2</sub>/carbonate mediation approach to steering the WOR pathway from 4e<sup>-</sup> to 2e<sup>-</sup>. Using fluorine-doped tin oxide electrode in carbonate solutions, we achieved high H<sub>2</sub>O<sub>2</sub> selectivity of up to 87%, and delivered unprecedented H<sub>2</sub>O<sub>2</sub> partial currents of up to 1.3 A cm<sup>-2</sup>, which represents orders of magnitude improvement compared to literature. Molecular dynamics simulations, coupled with electron paramagnetic resonance and isotope labeling experiments, suggested that carbonate mediates the WOR pathway to H<sub>2</sub>O<sub>2</sub> through the formation of carbonate radical and percarbonate intermediates. The high selectivity, industrial-relevant activity, and good durability open up practical opportunities for delocalized H<sub>2</sub>O<sub>2</sub> production.