Electrochemical generation of hydrogen peroxide from a zinc gallium oxide anode with dual active sites.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37019917.
- Also identified by DOI 10.1038/s41467-023-37007-9 and PMC identifier 10076521.
- 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 enables the conversion of H<sub>2</sub>O to H<sub>2</sub>O<sub>2</sub>. It holds distinct advantages to the O<sub>2</sub> reduction reaction, which is restricted by the inefficient mass transfer and limited solubility of O<sub>2</sub> in aqueous media. Nonetheless, most reported anodes suffer from high overpotentials (usually >1000 mV) and low selectivity. Electrolysis at high overpotentials often causes serious decomposition of peroxides and leads to declined selectivity. Herein, we report a ZnGa<sub>2</sub>O<sub>4</sub> anode with dual active sites to improve the selectivity and resist the decomposition of peroxides. Its faradaic efficiency reaches 82% at 2.3 V versus RHE for H<sub>2</sub>O<sub>2</sub> generation through both direct (via OH<sup>-</sup>) and indirect (via HCO<sub>3</sub><sup>-</sup>) pathways. The percarbonate is the critical species generated through the conversion of bicarbonate at Ga-Ga dual sites. The peroxy bond is stable on the surface of the ZnGa<sub>2</sub>O<sub>4</sub> anode, significantly improving faradaic efficiency.