Manipulating spin-polarization of Co-doped ZnFe₂O₄ for photocatalytic TC degradation

The rapid recombination of photogenerated electrons and holes was an enormous hindrance constraining the photocatalytic efficiency of photocatalysis, which could be effectively solved by inducing electron spin-polarization. Herein, a series of gradient ZnFe2-xCoxO4 (ZFCO-x) magnetic compounds with spin-polarization properties were synthesized by doping Co cation into ZnFe2O4, as well as the diffraction of x-rays characterization confirmed the successful synthesis of the samples. In photodegradation experiments, ZFCO-0.8 manifested improved photocatalytic degradation efficiency in TC removal experiments with visible-light exposure and external magnetic field. Furthermore, the photodegradation experiments exhibited that the degradation efficiency of ZFCO-x could be raised through Co doping and the photocatalytic degradation efficiency was significantly improved under an external magnetic field. The sample exhibiting the most prominent enhancement was ZFCO-x with doping content of x = 0.8, which displayed 48% photocatalytic degradation performance enhancement with a magnetic field. Density functional theory was used to calculate the density of states (DOS) of materials. The calculated DOS indicated that ZFCO-0.8 exhibited the most intense spin-polarization consistent with the results of the experiment. This work is anticipated to deliver an operating method for manipulating spin-polarization in photocatalytic semiconductors to improve photocatalytic degradation efficiency.