Efficient photocatalytic degradation of microplastics by constructing a novel Z-scheme Fe-doped BiO2-x/BiOI heterojunction with full-spectrum response: Mechanistic insights and theory calculations

Abstract

Recently, microplastics (MPs) have garnered significant attention as a challenging emerging pollutant to address. Here, a full-spectrum light-driven Fe-doping BiO_2-x/BiOI (FBI) Z-scheme heterojunction was constructed for efficiently degrading MPs in waters. Compared with BiO_2-x, Fe doping BiO_2-x, and BiOI, the optimal photocatalyst (40-FBI) can cause deep cracks in the polyethylene terephthalate (PET) within 10 hours under the irradiation of full-spectrum light. Meanwhile, FT-IR characterization revealed that the absorption peak intensities of the C-O group, C=O group, -CH stretching vibration, and -OH group on the MPs surface gradually increased with degradation time. A series of experiments and theory calculations revealed that the introduction of Fe creates impurity levels, accelerating the separation of photo-generated carriers and reducing the work function of BiO_2-x, thereby enhancing the transport of photo-generated carriers between Z-scheme heterojunctions. This study offers a valuable idea for designing an efficient photocatalyst by simultaneously introducing ion doping and constructing heterojunctions for enhancing MPs degradation.