文献速递|山东大学ACB:尖晶石氧化物的表面羟基： 过一硫酸盐活化过程中的双刃剑

第一作者：Yufei Han

通讯作者：周维芝 教授

通讯单位：山东大学土建与水利学院

DOI:10.1016/j.apcatb.2024.124849

Fig. 1. Structure and characterization of the samples: (A) XRD patterns of spinel oxides with different Mn content. (B) FTIR spectra of spinel oxides with different Mn content. (C) Nitrogen adsorption-desorption isotherms of CoFe2O4 and CoFeMnO4. (D) The SEM and TEM image of CoFeMnO4. XPS spectra of Co 2p (E), Fe 2p (F), Mn 2p(3 s) (G) and O 1 s (H) regions for CoFeMnO4 and CoFe2O4. (I) The surface hydroxyl density of CoFeMnO4 and CoFe2O4. (J) Adsorption energy of water on CoFeMnO4 and CoFe2O4. (K) Changes in the adjacent Co−O bond lengths of CoFeMnO4 and CoFe2O4 before and after water adsorption. In the DFT calculation, red balls are oxygen, blue balls are cobalt, orange balls are iron, cyan balls are manganese, yellow balls are sulfur, and white balls are hydrogen.

Fig. 2. Catalytic performance of the samples. (A) Performance for SMX degradation of different reaction systems (B) The kinetic fitting of SMX degradation in different reaction systems. (C) Comparison of the yield of CoFeMnO4 using scaled-up synthesis and small-scale synthesis. (D) Comparison of the activities of CoFeMnO4 synthesized on a large scale and on a small scale. (E) Comparison of normalized rate constant of SMX degradation for different catalysts. (F) Cycling performance of CoFeMnO4. Reaction conditions: Temperature = 25°C, pH = 7.0 ± 0.1, [SMX] = 20 μM, [PMS] = 0.1 mM. Catalyst dosage for Fig. 1A is 0.05 g/L, all other catalyst dosages are 0.2 g/L.

Fig. 3. Identification of the main ROS in the CoFeMnO4/PMS system. (A) Effects of different scavengers on SMX degradation in the reaction system. (B) EPR spectra with DMPO as the spin trap. (C) EPR spectra with TEMP as the spin trap. (D) I-t and OCP curves of CoFeMnO4 as working electrode. (E) Transformation of PMSO in CoFeMnO4/PMS system. (F) Transformation of PMSO in PMS alone system. (G) EIC spectrum of the 18O isotope labeling experiment on PMSO. (H) MS spectrum of the 18O isotope labeling experiment on PMSO. Reaction conditions: Temperature = 25°C, pH = 7.0 ± 0.1, [SMX] = 20 μM, [PMS] = 0.1 mM, [Catalyst] = 0.2 g/L.

Fig. 4. Identification of the active sites in the CoFeMnO4/PMS system. (A) Effect of phosphate on SMX degradation. (B) Effect of phosphate on PMS activation. (C) kobs of SMX degradation and PMS decomposition, inset is the correlation of the inhibition rate of phosphate on SMX degradation and PMS decomposition. (D) Effects of phosphate on the ATR-FTIR spectra of CoFeMnO4 in D2O suspension. (E) Effects of PMS on the ATR-FTIR spectra of CoFeMnO4 in D2O suspension. (F) Schematic diagrams of terminal hydroxyls and bridging hydroxyls on CoFeMnO4. (G) Adsorption energy and Bader charge of different hydroxyl sites on PMS. In the DFT calculation, red balls are oxygen, blue balls are cobalt, orange balls are iron, cyan balls are manganese, yellow balls are sulfur, and white balls are hydrogen. Reaction conditions: Temperature = 25°C, pH = 7.0 ± 0.1, [SMX] = 20 μM, [PMS] = 0.1 mM, [Catalyst] = 0.2 g/L.

Fig. 5. Reaction mechanism of the CoFeMnO4/PMS system. (A) The O 1 s (A), Co 2p (B), Fe 2p (C) and Mn 3 s (D) spectra of CoFeMnO4 before and after the reaction. (E) Differential charge of PMS when activated at different sites. (F) FTIR spectra of CoFeMnO4 before and after the reaction. (G) In situ ATR-FTIR of the activation process of PMS by CoFeMnO4 (in H2O). In the DFT calculation, red balls are oxygen, blue balls are cobalt, orange balls are iron, cyan balls are manganese, yellow balls are sulfur, and white balls are hydrogen.

Fig. 6. The influence of anions on the reaction system. Among them, (A), (B), (C) and (D) represent four anions: Cl–, HCO3–, SO42– and NO3–. (1) is the effect of the corresponding anions on SMX removal. (2) is the effect of the corresponding anions on PMS decomposition. (3) is the kobs of SMX removal and PMS decomposition in the system when the corresponding anions exist. The gray color represents the kobs for SMX degradation, while the colored sections represent the kobs for PMS decomposition. (4) is the correlation between SMX degradation and inhibition of PMS decomposition in the presence of the corresponding anions. (5) is the effect of corresponding anions on the ATR-FTIR spectra of CoFeMnO4 in D2O suspension. Reaction conditions: Temperature = 25°C, pH = 7.0 ± 0.1, [SMX] = 20 μM, [PMS] = 0.1 mM, [Catalyst] = 0.2 g/L.