Fabrication and photocatalytic degradation activity of core/shell ZIF-67@CoWO4@CoS heterostructure photocatalysts under visible light

Abstract

In this work, high photocatalytic degradation activity towered organic pollutants (methylene blue (MB) dye) has been achieved under visible light using new core/shell ZIF-67@CoWO4@CoS heterostructures. The optical, structural and morphological properties were studied using XRD, FE-SEM, EDX, UV-DRS, VSM, and BET surface area characterization methods. Noticeably, the photocatalytic degradation efficiency of the ZIF-67@CoWO4@CoS photocatalyst was higher to that of its individual-component complements (about 100% after 10 min of irradiation time). Furthermore, ZIF-67@CoWO4@CoS photocatalyst showed higher activity than ZIF-67@CoWO4 and ZIF-67@CoS nanocomposites. This enhanced photocatalytic degradation efficiency of ZIF-67@CoWO4@CoS can be attributed to the synergistic effects of ZIF-67, CoWO4 and CoS nanoparticles, and the narrow band gap energy of the synthesized core/shell ZIF-67@CoWO4@CoS heterostructure. The photocatalytic degradation of MB followed a pseudo-first-order kinetic model (K1 = 0.105 min−1). Moreover, the recyclability study exhibited that the ZIF-67@CoWO4@CoS photocatalyst was extremely stable and can be used eight times without considerable loss in its photocatalytic degradation activity. The results of this work underline the use of effective, low-cost and easily available ZIF-67@CoWO4@CoS photocatalyst for the decomposition of wide range of organic pollutants in wastewater under visible light irradiation.