Cobalt/nitrogen co-carved carbon nanorod for efficient Fenton-like reaction:Degradation efficacy,reaction mechanism and singlet oxygen generation

摘要

The Fenton-like process shows promising potential to generate reactive oxygen species for the reme-diation of increasingly environmental pollutants.However,the slow development of high-activity cata-lysts with strong stability and low leaching of metal ions has greatly inhibited scale-up application of this technology.Here,cobalt(Co)/nitrogen(N)atom co-curved carbon nanorod(CoNC)containing highly uniform CoN_(x)active sites is developed as a Fenton-like catalyst for the effective catalytic oxidation of various organics via peroxymonosulfate(PMS)activation with high stability.As confirmed by the exper-imental results,singlet oxygen(^(1)O_(2))is the dominant active species for the degradation of the organ-ics,with a proportion of 100%.Furthermore,density functional theory calculations indicate that CoN_(2)C_(2)is the most effective ligand structure with more negative adsorption energy for PMS and the shortest length Co-O bond,while the most reasonable generation pathway for^(1)O_(2)was CoN_(2)C_(2)-PMS→CoN_(2)C_(2)-OH∗→2O∗→^(1)O_(2).Further studies demonstrate that the electron can be transferred from the highest occupied molecular orbitals of the organics to the lowest unoccupied molecular orbitals of the PMS via CoN_(2)C_(2)action.In addition,the CoNC presents strong resistance to inorganic ions and natural organic matter in the Fenton-like catalysis process.The presence of CoN_(2)C_(2)active centre can significantly shorten the migration distance of the^(1)O_(2)generated from PMS activation,which further enhances the Fenton-like catalytic activity in terms of mineralising various organic contaminants with high efficiency over a wide pH range.