Crystal OH mediating pathway for hydrogen peroxide production via two-electron water oxidation in non-carbonate electrolytes.

Wang, Ruilin; Luo, Hao; Duan, Chengyu; Liu, Huimin; Sun, Mengdi; Zhou, Quan; Ou, Zheshun; Lu, Yinglong et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Water oxidation presents a promising avenue for hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) production. However, the reliance on alkaline bicarbonate electrolytes as an intermediate has limitations, such as H<sub>2</sub>O<sub>2</sub> decomposition and a narrow pH effectiveness range (7-9), restricting its utility across wider pH ranges. This study unveils a crystal OH mediating pathway that stabilizes SO<sub>4</sub>OH* as a crucial intermediate. Basic copper carbonate (Cu<sub>2</sub>(OH)<sub>2</sub>CO<sub>3</sub>) tablets, commonly found on cultural relics, exhibit the capability to generate H<sub>2</sub>O<sub>2</sub> in neutral or acidic non-bicarbonate electrolytes. By leveraging this crystal OH mediating strategy, considerable H<sub>2</sub>O<sub>2</sub> production in Na<sub>2</sub>SO<sub>4</sub> electrolytes is achievable. Notably, the H<sub>2</sub>O<sub>2</sub> production rate can reach 64.35 μmol h<sup>-1</sup> at 3.4 V vs. RHE in a 50 mL 0.5 M Na<sub>2</sub>SO<sub>4</sub> electrolyte. This research underscores the importance of crystal part in catalyst in catalyzing the 2e<sup>-</sup> water oxidation reaction, offering valuable insights for future investigations.