Defect- and nitrogen-rich porous carbon embedded with Co NPs derived from self-assembled Co-ZIF-8 @ anionic polyacrylamide network as PMS activator for highly efficient removal of tetracycline hydrochloride from water

Surface Nitrogen-Doped Carbon Decoration of Co Catalyst Supported on Mesoporous Carbon to Boost Peroxymonosulfate Activation for Antibiotics Degradation

“…In addition to quenching experiments, TEMP and DMPO were used as spin traps to determine the presence of 1 O 2 and other relevant radicals. As shown in Figure b, the EPR profile presents a strong TEMP– 1 O 2 signal, which can be attributed to (i) the reaction of HSO 5 – and SO 5 2– () during self-PMS activation induced by O L species in the catalyst (confirmed by the XPS results discussed above) and (ii) the formation of reactive oxygen (O*) that can activate PMS and generate nonradical 1 O 2 species ( and ) . Additionally, Figure d confirms the presence of DMPO– • OH and DMPO–SO 4 •– , which is consistent with the quenching experiment results.…”

“…Overall, such species can play a key role in promoting PMS activation and antibiotic degradation. 46,47 As shown in Figure 5c, the N 1s spectra of Co/MC@NC catalysts present the characteristic peaks of pyridinic N, Co−N x , pyrrolic N, and graphitic N at 398.4, 399.0, 400.0, and 401.3 eV, respectively. 8,48,49 Among these species, pyridinic N normally exhibits thermal instability, turning into stable graphitic N at a high carbonization temperature.…”

“…As shown in Figures 5a and S3b, all of the catalysts exhibit the characteristic peak of surface-adsorbed oxygen (O sur ) at 532.4 eV. 46 Compared to Co/MC, after surface NC decoration, Co/MC@NC exhibits an additional characteristic peak at ∼529.8 eV, which can be attributed to the lattice oxygen (O L ). 43 Interestingly, with increased carbonization temperature from 700 to 900 °C, the intensity of the O L peak increases considerably.…”

“…For the C 1s spectra, all of the catalysts show C−C/C−H and C�O species with characteristic peaks located at 284.6 and 286.3 eV, respectively. 46 The C 1s spectra of Co/MC@NC catalysts (Figure 5a) show a C−N peak at ∼285.3 eV (induced by NC surface decoration). The peak intensity slightly increases with increasing carbonization temperature.…”

“…This behavior is observed from the peak area of pyridinic N in Co/MC@NC-1100 being considerably smaller than that of other catalysts. 50,51 Co−N x is recognized as one of the dominant active centers for PMS activation, 46,50 while graphitic N is the active site for 1 O 2 generation, directly degrading antibiotics in a non-free-radical pathway. 8 As shown in Figure 5d, the Co 2p spectra of Co/MC@NC catalysts exhibit different characteristic peaks at 803.8, 796.0, 786.0, 782.1, and 780.2 eV, indicating the presence of a Co 2p shake-up satellite, Co 2+ , Co−N x , Co 3+ , and Co 0 , respectively.…”