Fabrication of nitrogen-doped graphene nanosheets anchored with carbon nanotubes for the degradation of tetracycline in saline water

Understanding the active sites and associated reaction pathways of metal-free carbocatalysts in persulfate activation and pollutant degradation

“…Specifically, the N-5 content of the carbocatalyst increased after use, while those of N-Q and N-6 decreased. 78,79 Correspondingly, the contents of N-Q and N-6 were increased to a value near the fresh catalyst after restoring the used carbocatalyst. The N-Q and N-6 also coexisted in an N-doped GO catalyst for the cooperative catalytic activation of PDS for phenol and oxalic acid degradation.…”

“…If the numbers of CO and C-O groups of the catalysts become smaller and larger after the AOP while turning to be increased and reduced after catalyst regeneration treatments, respectively, the CO groups can be assumed to be the active sites. 79 Hydroxyl (-OH) groups. Oxygen groups could be effectively removed from the commercial CNT surface via thermal annealing, allowing the zeta potential of the surface-charged CNT to be less negative in neutral solutions and strengthening the adsorption interactions with PDS anions for the formation of metastable CNT-PDS* intermediate due to the weaker electrostatic repulsion.…”

“…If the numbers of CO and C–O groups of the catalysts become smaller and larger after the AOP while turning to be increased and reduced after catalyst regeneration treatments, respectively, the CO groups can be assumed to be the active sites. 79…”

“…11a–d. 79 Such dual N configurations' cooperation effects result in the direct electron transfer pathway for the activation of PMS and PDS to mineralize TC. 78,79 XPS can be employed to monitor the activity of different N configurations.…”

“…79 Such dual N configurations' cooperation effects result in the direct electron transfer pathway for the activation of PMS and PDS to mineralize TC. 78,79 XPS can be employed to monitor the activity of different N configurations. Specifically, the N-5 content of the carbocatalyst increased after use, while those of N-Q and N-6 decreased.…”