Fe doping induced selenium vacancy on cobalt selenide for enhanced hydrogen peroxides production

Electrocatalytic two-electron oxygen reduction reaction (2e-ORR) pathway for hydrogen peroxides (H2O2) generation has emerges as an appealing alternative to conventional anthraquinone craft. In this work, Fe doped CoSe was synthesized via hydrothermal and subsequent high temperature (HT) annealing process. The doping of trace amount of Fe could tune the crystal growth direction and induce the generation of Se vacancy during annealing. During the Electrocatalytic measurement, the Faraday efficiency of 2e-ORR can reach 99.1%, 83.2% and 93.6% in 0.1 M KOH, 0.1 M Na2SO4, and 0.05 M H2SO4, respectively. Under the neutral condition, the production rate of H2O2 reached 18.37 mmol L-1 in 120 min. Moreover, Fe-CoSe-HT exhibits good stability and Fe2+ regeneration during flow-Fenton reaction. Hence, the dual role of selenium-vacancy-enriched Fe-CoSe-HT greatly enhanced selectivity of 2e-ORR and accelerated Fe reduction, resulting in promoted center dot OH radical generation and organic pollutants treatment.