Rationally designed ZnFe1.2Co0.8O4/BiVO4 S-scheme heterojunction with spin-polarization for the elimination of antibiotic

Recently, the regulation of electronic spin polarization has attracted considerable interest as an effective strategy to mitigate the rapid recombination of photo-generated charges. However, current research predominantly targets individual photocatalysts, where the efficiency of charge separation still has significant room for improvement. Herein, a ZnFe_1.2Co_0.8O₄ (ZFCO) and BiVO₄ (BVO) S-scheme heterojunction was developed, which synergistically promoted charge separation through the S-scheme heterojunction and spin polarization, and further enhanced the photocatalytic performance in removing organic pollutants under an external magnetic field. Experimental results revealed that under sole light irradiation, ZB-1.5 (ZFCO : BVO ​= ​3 : 2) demonstrated optimal performance, with a reaction rate constant (k) for tetracycline (TC) degradation of 0.0146 ​min⁻¹. Under light irradiation and magnetic field conditions, the reaction rate constant (k) of ZB-1.5 for TC degradation increased to 0.0175 ​min⁻¹, indicating enhanced photocatalytic performance. DFT calculations indicated that ZFCO exhibited the spin polarization. Photoluminescence measurements demonstrated that the S-scheme heterojunction structure improved the charge separation efficiency. In addition, possible degradation pathways and toxicity were assessed, indicating successful detoxification. This work provides some useful insights into utilizing S-scheme heterojunctions to develop photocatalysts with efficient separation of photo-generated charges.