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

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.