CoSe2 supported single Pt site catalysts for hydrogen peroxide generation via two‐electron oxygen reduction

Abstract Electrocatalytic oxygen reduction reaction (ORR) to prepare H 2 O 2 in acidic medium has the advantages of green, safety, and portability, which shows broad development prospects. However, it still suffers from low catalyst activity, insufficient selectivity, and high cost. Herein, Pt 1 /CoSe 2 with ultralow 0.01 wt.% Pt atomic distribution was synthesized by a simple hydrothermal method. The Pt 1 /CoSe 2 with ultralow Pt content exhibits high activity, high selectivity, and long‐term stability for ORR to H 2 O 2 in O 2 ‐saturated 0.1 M HClO 4 . The onset potential is as low as 0.75 V versus reversible hydrogen electrode (RHE), H 2 O 2 selectivity is as high as 84% (0.4 V vs. RHE), and the electron transfer number is 2.3 (0.4 V vs. RHE). Moreover, the hydrogen peroxide yield using the flow cell testing is 110.02 mmol g cat. −1 h −1 with high Faradaic efficiency of 78% (0 V vs. RHE) at 0.1 M HClO 4 , and the catalyst did not deactivate significantly after 60 h stability testing. Mechanistic studies and in situ X‐ray photoelectron spectroscopy characterization confirm that the ultralow Pt content on CoSe 2 can effectively regulate the electronic structure of Co as the real active site around the Pt site, which gives a suitable ∆ dp value (the difference between the d‐band center of the active metal site and the p‐band center of the terminal oxygen in *OOH), provides an ideal *OOH binding energy, and inhibits the O–O bond breakage. This work successfully improves the intrinsic activity of the Co active sites around Pt in Pt 1 /CoSe 2 for acidic ORR to H 2 O 2 by constructing ultralow‐content Pt single atom.