The photocatalytic degradation performance and mechanism of rod-like hollow derivatives from Co-doped MIL-68(In) under visible light

In this study, we synthesized a convenient and efficient composite photocatalyst, In2O3/Co3O4 from the pyrolysis of Co-doped MIL-68(In). Structural characterization indicates that the composite material exhibited a rod-like hollow structure, thus increasing the specific surface area. Meanwhile, In2O3/Co3O4 forms a PN heterojunction, which reduces the recombination rate of photogenerated hole-electron pairs. Moreover, the visible light absorption ability of this material is enhanced and it has good catalytic properties. Under visible light, the removal rate of tetracycline (TC) reaches 94% by the In2O3/Co3O4 in 90 min, and the reaction constant is 0.02393 min−1, which is 6.86 and 5.56 times of the single component In2O3 and Co3O4, respectively. As shown by free radical quenching experiments and electron paramagnetic resonance (EPR) test, h+ and •O2− play an important role in degrading TC into small molecule intermediates in the catalytic process.