Abundant oxygen vacancies constructed by deep reduction strategy to achieve ultra-high peroxomonosulfate activation efficiency for degrading organic pollutions in water

Over-Reduced Core–Shell Au@CoOx-Co with Strong Interfacial Interactions for Photoassisted Peroxymonosulfate Activation

“…Scanning transmission electron microscopy HAADF image and element mapping (Figure d) exhibit the core–shell structure, where gold cores are enclosed by cobalt oxide shells. High-resolution TEM (HRTEM) image (Figure c) displays a lattice spacing of 2.41 Å, attributable to the (111) facets of metallic Au, the 2.17 Å spacing matching with (200) facet of CoO, the 2.07 Å spacing matching with (111) facet of Co(0), and 2.52 Å corresponding to (311) facet of spinel Co 3 O 4 . , Compared with the standard lattice parameters of metallic Co(0) and spinel Co 3 O 4 , a slight expansion in the measured lattice spacings was observed. This implies the interfacial strain effects between the Au core and cobalt oxide shell.…”

“…Using electron paramagnetic resonance spectroscopy (EPR), the concentrations of OVs and different free radical species were examined with the Au@CoO x -Co catalyst under identical conditions to photocatalytic testing. 19 Data were captured at 5 min after the addition of PMS, the respective peak generation time points. Impressively, under light irradiation versus dark conditions, significantly enhanced intensities of • OH, SO 4…”

“…16−18 For environmental remediation, cobalt (Co)-based nanomaterials have been widely used as catalysts to activate peroxymonosulfate (PMS) to form reactive radicals. 19,20 Defect engineering, in particular, oxygen vacancies (OVs), has been shown to effectively tune the electronic structure of transition metal oxides and facilitate electron transfer to enhance the activation efficiency of PMS. OVs in metal oxide surfaces serve as critical reactive sites for the adsorption, activation, and mediation of key intermediates involved in the subsequent catalytic oxidation processes.…”

“…21−23 Cao et al utilized deep reduction treatment of Co 3 O 4 to introduce abundant OVs, achieving 100% degradation of sulfadiazine (SD) within 1 min with ultrahigh efficiency, possessing a degradation rate constant (k) value as high as 5.9 ± 0.2 min −1 . 19 Zhang et al doped Co into the lattice of ZnFe 2 O 4 spinel to form ZnFe 0.8 Co 0.4 O 2.4 nanoparticles with OV-rich surfaces, which exhibited high activity and stability in activating PMS for degrading refractory pollutants. 24 However, creating OV-rich cobalt oxide structures often requires post-treatment via costly and energy-consuming thermal processes.…”

“…For environmental remediation, cobalt (Co)-based nanomaterials have been widely used as catalysts to activate peroxymonosulfate (PMS) to form reactive radicals. , Defect engineering, in particular, oxygen vacancies (OVs), has been shown to effectively tune the electronic structure of transition metal oxides and facilitate electron transfer to enhance the activation efficiency of PMS. OVs in metal oxide surfaces serve as critical reactive sites for the adsorption, activation, and mediation of key intermediates involved in the subsequent catalytic oxidation processes. − Cao et al utilized deep reduction treatment of Co 3 O 4 to introduce abundant OVs, achieving 100% degradation of sulfadiazine (SD) within 1 min with ultrahigh efficiency, possessing a degradation rate constant ( k ) value as high as 5.9 ± 0.2 min –1 . Zhang et al doped Co into the lattice of ZnFe 2 O 4 spinel to form ZnFe 0.8 Co 0.4 O 2.4 nanoparticles with OV-rich surfaces, which exhibited high activity and stability in activating PMS for degrading refractory pollutants .…”