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 (Se₂^2-, S₂^2-, and O^2-) 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.

Supplementary material (additional experimental procedures, characterizations, and computational details) is available in the online version of this article at 10.1007/s12274-022-5160-2.