Fabrication of a Z-scheme CeO2/Bi2O4 heterojunction photocatalyst with superior visible-light responsive photocatalytic performance

Abstract

In this study, a CeO 2 /Bi 2 O 4 Z-scheme heterojunction was prepared by using a facile hydrothermal method. After 40 min of visible-light irradiation, this composite photocatalyst displayed superior photocatalytic activity for removing levofloxacin and methyl orange than pure CeO 2 and Bi 2 O 4 , achieving the degradation efficiencies of 88.75% and 90.3%, respectively. According to the results of transient photocurrent response, electrochemical impedance spectroscopy, and photoluminescence, CeO 2 /Bi 2 O 4 heterojunction photocatalyst exhibited efficient photoinduced charges separation. The enhanced photocatalytic performance was due to synergy between efficient separation of photogenerated carriers and increased solar absorption. A Z-scheme heterojunction between CeO 2 and Bi 2 O 4 was formed, which was contributed by the well-matched band structure, facilitating the fast transfer and separation of carriers. The active species, including h + , O 2 · – , and ·OH, play key roles in the photodegradation reactions, demonstrated by electron spin resonance spectroscopy. High-performance liquid chromatography-mass spectrometry was used to identify the probable degradation path of levofloxacin. This work will benefit the design of efficient Z-scheme heterojunction photocatalysts for environmental remediation. • MO and LVF were used to evaluate the photocatalytic activities. • HAADF-STEM, ESR and HPLC-MS analysis were used to analyze the mechanism. • The separation of photoinduced carriers was testified by photocurrent, PL and SPV. • A possible mechanism of CeO 2 /Bi 2 O 4 Z-scheme heterojunction is proposed.