Ultrathin single-crystal PtSe₂ nanosheets for high-efficiency O₂ electroreduction to H₂O₂

Electrochemical synthesis of H₂O₂via a two-electron oxygen reduction reaction (2e^- ORR) has emerged as a promising alternative to the anthraquinone process. However, the strong competition from the 4e^- pathway severely limits its activity and selectivity, especially for Pt-based catalysts. Herein, ultrathin single-crystal PtSe₂ nanosheets were successfully prepared via an in situ selenization process using commercial Pt/C as a precursor, demonstrating an exclusive 2e^- ORR pathway compared to the 4e^- pathway of commercial Pt/C, delivering a high H₂O₂ selectivity over a wide pH range (>80%, up to 94.1%). Furthermore, in situ infrared spectroscopy results revealed Pt as an active center, accompanied by the key intermediate OOH* adsorption and HOOH formation.