Cobalt-based ZIF coordinated hybrids with defective TiO2-x for boosting visible light-driven photo-Fenton-like degradation of bisphenol A

Abstract

Designing heterostructure of photocatalyst as an efficient approach to boost visible light-driven photocatalytic degradation, we prepared a series of cobalt-based ZIF coordinated with defective TiO2-x, denoted as B–TiO2-x@ZIF-67 composites, through wrapping defective B–TiO2-x on ZIF-67 for promoting photocatalytic degradation efficiency of biphenyl A. The B–TiO2-x@ZIF-67 composites displayed superior photocatalytic performance to pure TiO2-x or ZIF-67 because of faster separation of photogenerated charge carriers and more suitable redox potentials. Such a novel photo-Fenton-like system composed of B–TiO2-x@ZIF-67/H2O2/visible light accelerated the peroxidative degradation of biphenyl An up to a removal efficiency of 95.30%, which is also higher than that of photocatalysis or Fenton-like reaction alone. In addition, the degradation efficiency of biphenyl A is unchanged after catalyst reuse of four cycles. Integrating the trapping experiments and electrochemical analysis, we found the oxygen vacancy on B–TiO2-x capturing the electrons to promote the separation of photogenerated charges, meanwhile the Co(II) in the composite decomposed hydrogen peroxide (H2O2) to produce more •OH radical. Both of them mutually boosted the removal efficiency. Finally, feasible degradation pathways of biphenyl A were proposed based on the assay of LC-MS spectrometry. This strategy offers a novel insight into fabrication of Co-ZIF-based TiO2-x materials and application to visible light-driven photocatalytic and Fenton-like degradation reaction.