Electrochemical oxygen reduction to hydrogen peroxide at practical rates in strong acidic media.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35610199.
- Also identified by DOI 10.1038/s41467-022-30337-0 and PMC identifier 9130276.
- 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 oxygen reduction to hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) in acidic media, especially in proton exchange membrane (PEM) electrode assembly reactors, suffers from low selectivity and the lack of low-cost catalysts. Here we present a cation-regulated interfacial engineering approach to promote the H<sub>2</sub>O<sub>2</sub> selectivity (over 80%) under industrial-relevant generation rates (over 400 mA cm<sup>-2</sup>) in strong acidic media using just carbon black catalyst and a small number of alkali metal cations, representing a 25-fold improvement compared to that without cation additives. Our density functional theory simulation suggests a "shielding effect" of alkali metal cations which squeeze away the catalyst/electrolyte interfacial protons and thus prevent further reduction of generated H<sub>2</sub>O<sub>2</sub> to water. A double-PEM solid electrolyte reactor was further developed to realize a continuous, selective (∼90%) and stable (over 500 hours) generation of H<sub>2</sub>O<sub>2</sub> via implementing this cation effect for practical applications.