In-situ fabrication of 3D hierarchical flower-like β-Bi2O3@CoO Z-scheme heterojunction for visible-driven simultaneous degradation of multi-pollutants

Abstract

Development of an efficient heterojunction catalyst with a superior visible-light driven activity is regarded as a promising strategy to decontaminate organic wastewater. Herein, a novel direct Z-scheme β-Bi2O3@CoO heterojunction was well designed and successfully fabricated by in situ incorporating the two energy band-matched semiconductors. The obtained β-Bi2O3@CoO hybrid presented a unique 3D hierarchical structure with a mass of open channels and mesoporous, which afforded not only rapid mass transfer of targets but also good light-harvesting in view of the multiple reflections. Compared to the pristine β-Bi2O3 and CoO, the β-Bi2O3@CoO hybrid exhibited remarkably improved photocatalytic activity towards the simultaneous degradation of chlorotetracycline (CTC), tetracycline hydrochloride (TCH), oxytetracycline (OTC) and nitrobenzene (NB) under visible-light irradiation. The possible intermediates and degradation pathways were also tracked by mass spectra (MS) analysis. Moreover, a direct Z-scheme charge transfer mechanism in the intimate contact interface between β-Bi2O3 and CoO was verified for the improved catalytic activity, endowing the effective separation/transportation of the photo-excited charge carriers and maintenance of the strong redox ability in β-Bi2O3@CoO heterojunction. The present work affords a simple approach to design and construct 3D hierarchical direct Z-scheme photocatalysts with promising applications in water environment remediation.