Ultrathin single-crystal PtSe 2 nanosheets for high-efficiency O 2 electroreduction to H 2 O 2 .

Electrochemical synthesis of H 2 O 2 via 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 PtSe 2 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 H 2 O 2 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.