Synthesis of Bi2S3/Bi2WO6 hierarchical microstructures for enhanced visible light driven photocatalytic degradation and photoelectrochemical sensing of ofloxacin

Ofloxacin has been a severe threat to the ecological system due to its perseverance. The extensive use partakes in toxic effects on both ground and surface water even in low concentrations. It is quite critical to design materials as platform that can have direct sensing and can also promote remediation. Herein for the purpose, hierarchical Bi2S3 propelled Bi2WO6 was designed through topotactic transformation of Bi2WO6 in the presence of thiourea under controlled hydrothermal atmosphere. Different weight percent Bi2S3/Bi2WO6 was synthesized for evaluation of ofloxacin photooxidation. The results suggested that 10 wt% Bi2S3/Bi2WO6 microstructures (87%) were efficiently reliable for visible light induced photocatalysis in comparison to pristine Bi2WO6 (78%) and Bi2S3 (21%) structures. The intact interfacial heterojunction as evident from high resolution imaging and photocurrent measurement advocates the acceleration in the electron transfer process in 10 wt% Bi2S3/Bi2WO6 (0.58 μA/cm2) in comparison to pure-Bi2WO6 (0.27 μA/cm2) and Bi2S3 (0.23 μA/cm2). Furthermore, 10 wt% Bi2S3/Bi2WO6/FTO modified electrode was explored as novel anode sensor that exhibited predominant performance for ofloxacin detection in a wide linear range from 1 µM to 100 µM and limit of detection obtained to be 0.906 µM (0.9 ng/mL). The presented strategy implies that such Bi2S3/Bi2WO6 heterojunction microstructure could be exploited in development of multifarious detection and remediation through photoelectrochemistry.