Metastable Hexagonal Phase SnO2 Nanoribbons with Active Edge Sites for Efficient Hydrogen Peroxide Electrosynthesis in Neutral Media

Abstract Electrochemical two‐electron oxygen reduction reaction (2 e − ORR) to produce hydrogen peroxide (H 2 O 2 ) is a promising alternative to the energetically intensive anthraquinone process. However, there remain challenges in designing 2 e − ORR catalysts that meet the application criteria. Here, we successfully adopt a microwave‐assisted mechanochemical‐thermal approach to synthesize hexagonal phase SnO 2 (h‐SnO 2 ) nanoribbons with largely exposed edge structures. In 0.1 M Na 2 SO 4 electrolyte, the h‐SnO 2 catalysts achieve the excellent H 2 O 2 selectivity of 99.99 %. Moreover, when employed as the catalyst in flow cell devices, they exhibit a high yield of 3885.26 mmol g −1 h −1 . The enhanced catalytic performance is attributed to the special crystal structure and morphology, resulting in abundantly exposed edge active sites to convert O 2 to H 2 O 2 , which is confirmed by density functional theory calculations.