Hollow In2O3@ZnFe2O4 heterojunctions for highly efficient photocatalytic degradation of tetracycline under visible light

Abstract

Visible-light active hollow In₂O₃@ZnFe₂O₄ heterojunctions are obtained through loading ZnFe₂O₄ nanosheets on hollow In₂O₃. First, uniform-size hollow In₂O₃ is prepared via thermal annealing of hexagonal In-MIL-68. Then layered double hydroxide (ZnFe-LDH) nanosheets are electrodeposited on the outer surfaces of the hollow In₂O₃ and annealed into ZnFe₂O₄. This unique design incorporates two oxide semiconductors into a Z-scheme heterojunction with hollow structure and nanosheet subunits, which can enhance visible-light absorption, inhibit the recombination of photogenerated charges and expose abundant active sites for further reaction. Thus, the resulting heterostructures exhibit a more efficient degradation efficiency of tetracycline (TC) under visible-light irradiation. The optimized In₂O₃@ZnFe₂O₄ photocatalyst exhibits a 90% photodegradation rate of TC (50 mg L⁻¹) in 30 min. In addition, the In₂O₃@ZnFe₂O₄ heterojunction shows excellent cycling stability and can be easily separated for recycling in view of its excellent stability and unique magnetic properties, which are advantageous for further application in environmental purification.