Enhanced photocatalytic activation of peroxymonosulfate by CeO2 incorporated ZnCo-layered double hydroxide toward organic pollutants removal

In this study, ceria nanosheets incorporated zinc cobalt-layered double hydroxide composites (ZnCo-LDH@CeO2) were prepared and employed as a heterogeneous photocatalyst to degrade contaminants in combination with peroxymonosulfate (PMS). The morphologies and physicochemical properties of the as-prepared photocatalysts were characterized by various technologies. The ZnCo-LDH@CeO2 /PMS system exhibited the highest photocatalytic removal performance among a series of catalytic schemes with phenol (20 mg/L) as model compound and 99.8% removal was achieved after 30 min reaction under optimal conditions with 0.8 g/L PMS and 0.2 g/L catalyst at room temperature. The enhancement of more efficient separation and transportation of photogenerated electrons and holes for ZnCo-LDH@CeO2 than the two individual units was determined by transient photocurrent responses and electrochemical impedance spectroscopy instruments. The generated oxidizing species including SO4 center dot-, (OH)-O-center dot, O-center dot(2)-, and h(+) during the degradation process were analyzed by quenching experiments and electron paramagnetic resonance spectra, and the possible degradation mechanism was proposed. The satisfactory reusability and wide applications of ZnCo-LDH@CeO2 /PMS/vis system indicated a class of promising technology for various non-biodegradable organic pollutants remediation.

Automated summary

In this study, ceria nanosheets incorporated zinc cobalt-layered double hydroxide composites were used as a heterogeneous photocatalyst in combination with peroxymonosulfate to degrade contaminants. The ZnCo-LDH@CeO2 /PMS system showed excellent photocatalytic removal performance, with 99.8% removal of phenol achieved in 30 minutes under optimal conditions. The efficient separation and transportation of photogenerated electrons and holes in ZnCo-LDH@CeO2 contributed to its enhanced performance.