Anion-tuned nickel chalcogenides electrocatalysts for efficient 2e− ORR towards H2O2 production in acidic media

Electrocatalytic 2e− oxygen reduction reaction (2e− ORR) is a promising approach to producing H2O2 at ambient temperature and pressure especially in acidic media, which, however, is hindered by the high cost of precious metal-based electrocatalysts. Hence, the development of efficient earth-abundant electrocatalysts and reaction mechanism exploration for H2O2 production by 2e− ORR in acidic solution are critically important but remain challenging at present. In this work, NiSe2 has been developed as a novel and high-performance 2e− ORR electrocatalyst in acidic media, moreover, using nickel chalcogenides as the models, the influence of different anion species (Se22−, S22−, and O2−) on 2e− ORR electrocatalytic performance of the catalysts has been investigated. The synthesized NiSe2 exhibits outstanding 2e− ORR performance of high selectivity (90%) and long-term durability (12 h). The maximum H2O2 concentration of NiSe2 reaches 988 ppm, which is the highest among all the reported transition metal chalcogenides. This work demonstrates a novel point of view in anion tuning for designing high-efficiency transition-metal-based electrocatalysts for 2e− ORR.