Synergistic photoelectrocatalytic degradation of tetracycline using a novel Z-scheme Zn0.5Ni0.5Fe2O4/SiNWs heterostructure: Towards sustainable antibiotic remediation

Abstract

Photoelectrocatalytic technology (PEC) is an emerging green and sustainable technology for treating antibiotic wastewater. However, its effectiveness is limited by the recombination of photogenerated carriers. To address this issue, the Fenton reaction, an advanced oxidation process, can be coupled with PEC technology to enhance the oxidative degradation of antibiotic wastewater. This research involved creating a Zn_0.5Ni_0.5Fe₂O₄/silicon nanowires (SiNWs) Z-type heterojunction through the spin coating technique, which was then utilized in the PEC coupled Fenton reaction to break down antibiotic wastewater. The inherent electric field and the voltage applied hastened the segregation of e⁻ and h⁺ within the system. These advantages make the Zn_0.5Ni_0.5Fe₂O₄/SiNWs heterojunction highly efficient in removing various antibiotics, including tetracycline (TC), ciprofloxacin (CIP), amoxicillin (AMX), and levofloxacin (LVX). In particular, the Zn_0.5Ni_0.5Fe₂O₄/SiNWs heterojunction demonstrated an 82.21% degradation efficiency for TC, exhibiting a kinetic constant (k) of 0.02688 min⁻¹, a rate 2.82 times (4.80 times) greater than that of SiNWs. Experimental findings reveal that Zn_0.5Ni_0.5Fe₂O₄/SiNWs exhibit superior light absorption properties and a reduced rate of photogenerated charge recombination. The doping of Zn_0.5Ni_0.5Fe₂O₄ effectively improves the catalytic performance of SiNWs. This research offers fresh insights into researching PEC-coupled Fenton reaction methods for the degradation of antibiotics and paves the way for advancing the creation of more potent photoelectrochemical catalysts in the future.