Xiaoze Yin,Huaqin Yin,Renjie Wang,Jinnan Wang,Aimin Li
Novel Fenton-like catalyst HKUST-1(Cu)/MoS2-3-C with a non-equilibrium-state surface was constructed for selective degradation of phenolic contaminants. Electron-polarized distribution facilitated the formation of σ-Cu-ligand between electron-poor Cu centre and phenolic compounds, which not only enhanced radicals generation but also accelerated the Cu(I)/Cu(II) redox. Meanwhile, ≡Mo–OOSO3−complexes formed by the electron-rich Mo centre and peroxymonosulfate (PMS), could directly oxidize phenolic contaminants with the generation of SO4•−. The radical quenching experiments and EPR tests indicated that both SO4•−and•OH played a dominant role in the reaction. Additionally, O2could be reduced to O2•−by OVs and subsequently converted into1O2over the Mo centre. DFT calculation, FT-IR, and in situ Raman spectra analysis results demonstrated that phenolic compounds and PMS were respectively adsorbed by electron-poor Cu centre and electron-rich Mo centre, favouring the electrons transfer from phenolic contaminants to Mo centre for PMS activation. With synergistic effects of σ-Cu-ligand and ≡Mo–OOSO3−complexes, HKUST-1(Cu)/MoS2-3-C achieved a high degradation rate of phenolic contaminants and utilization efficiency of PMS.Keywords:fenton-like catalyst;non-equilibrium-state surface;σ-Cu-ligand;≡Mo–OOSO3−complex;phenolic contaminants degradation
Zhiqun Xie,Jiali Zhou,Jinnan Wang,Corvini Philippe François-Xavier,Thomas Wintgens
Novel Fenton-like catalyst γ-Cu-Al 2 O 3 -Bi 12 O 15 Cl 6 with electron-poor Cu centre and electron-rich Bi centre was synthesized for selective degradation of phenolic compounds. Different from electron-rich Cu centre catalysts, the electron-poor Cu centre, which was induced by high electronegativity of Bi, could facilitate the formation of σ-Cu-ligand with phenolic compounds. On one hand, H 2 O 2 could directly oxidize σ-Cu-ligand to HO-adduct radicals with the generation of OH. Meanwhile, Cu(II) in the σ-Cu(II) complexes could be reduced to Cu(I) by oxidization of the HO-adduct radicals to hydroxylation products. Such reaction not only prevented Cu(II) from oxidizing H 2 O 2 to HO 2 /O 2 − but also enhanced the redox cycle of Cu(II)/Cu(I), which improved the catalytic activity and H 2 O 2 utilization. On the other hand, although the σ-Cu-ligand was gradually decreased with the decrease of phenolic compounds, dual-reaction centre played the dominant role in catalytic reaction . In addition, large amounts of oxygen vacancies (OVs) are formed in Bi 12 O 15 Cl 6 during the calcining process (BiOCl→Bi 12 O 15 Cl 6 ) , which can also increase the generation of OH. Thus, both electron-rich Bi center and OVs could still reduce H 2 O 2 to · OH for organics degradation even without the formation of σ-Cu-ligand. Being attributed to the synergistic effect of σ-Cu-ligand, dual-reaction centre and OVs mentioned above, γ-Cu-Al 2 O 3 -Bi 12 O 15 Cl 6 achieved high catalytic activity for phenolic compounds degradation and utilization efficiency of H 2 O 2 (η). In addition, various analytic methods (XPS, TPR, FT-IR, Raman, EPR and solid-state EPR) were used to prove the synergistic effect of the electron-poor/rich centre, σ-Cu-ligand and OVs of catalyst.