首页|Cu-doped Ni-LDH with abundant oxygen vacancies for enhanced methyl 4-hydroxybenzoate degradation via peroxymonosulfate activation: key role of superoxide radicals
Cu-doped Ni-LDH with abundant oxygen vacancies for enhanced methyl 4-hydroxybenzoate degradation via peroxymonosulfate activation: key role of superoxide radicals
扫码查看
点击上方二维码区域，可以放大扫码查看
原文链接
NSTL
Elsevier
? 2021 Elsevier Inc.Oxygen vacancies (OVs) were introduced into Ni-based layered double hydroxides (LDHs) through Cu doping, and the catalytic performance of the resulting NixCu-LDHs were investigated for peroxymonosulfate (PMS) activation and methyl 4-hydroxybenzoate (MeP) degradation. Compared with that of Ni-LDH, the catalytic performance of NixCu-LDHs were significantly enhanced and increased with increasing OV content in the catalysts, indicating that Cu doping introduced OVs into NixCu-LDHs and greatly improved their catalytic activity with PMS. Quenching experiments and EPR analyses confirmed that oxidation processes dominated by superoxide radicals (O2??) and singlet oxygen (1O2), rather than sulfate radicals (SO4??) or hydroxyl radicals (?OH) used by traditional LDH catalysts, were responsible for MeP degradation by Ni15Cu-LDHs. In addition, quenching experiments with different systems showed the fate of reduced SO4??and ?OH, and demonstrated that O2?? and 1O2 concentrations grew with increasing OV content, confirming that the presence of OVs affected the process of PMS activation. Notably, O2?? mainly originated from adsorbed oxygen or dissolved oxygen (DO) by acquiring electrons from OVs in Ni15Cu-LDHs, since OVs possess abundant localized electrons. Consequently, an OV-mediated oxidative mechanism was proposed for Ni15Cu-LDHs/PMS. This study provides new clues for enhancing the catalytic performance of LDH catalysts by introducing OVs via metal doping in PMS-based AOPs systems.
NSTL
Elsevier
