In Situ Synthesis of Magnetically Recoverable Nife2o4/T-Bivo4/Bi2MoO6 Ternary Heterojunction for Ciprofloxacin Degradation and H2 Evolution

Abstract

Rational design of novel conjugated step-scheme (S-scheme) multijunction heterostructure with synergistic charge channelization, superior light harvesting efficiency and strong redox ability is a pioneering approach to mimic natural photosynthesis process. A mild CTAB assisted one pot reflux synthesis route is used for in situ integration of MOF-derived NiFe2O4 with t-BiVO4 and Bi2MoO6 to prepare NiFe2O4/t-BiVO4/Bi2MoO6 ternary composites. Morphologically, fine dispersion of NiFe2O4 (NFO) quantum dots over Bi2MoO6 (BMO) and t-BiVO4 (BVO) nanoplates yielded three types of microscopic heterojunctions among BMO-BVO, BVO-NFO and BMO-NFO phases. The ternary composites displayed important physicochemical attributes including high surface area, strong optical absorption, superior charge mobility and higher excited state lifetime which accounted for its improved photocatalytic activity towards ciprofloxacin degradation (>99% in 90 min) and H2 evolution (1.11 mmolh−1g−1, photon conversion efficiency 18.5%). Kinetics study revealed 12–55 fold higher ciprofloxacin photodegradation activity and 31–41 times higher H2 evolution rate for the ternary composite in comparison to the pure semiconductors. A conjugated S-scheme charge transfer mechanism has been deduced from comprehensive band position analysis and radical trapping study to explain the enhanced photocatalytic activity.