Excellent performance of AgVO3@ZIF(Zn, Co) interfacial heterojunction for photodegradation of organic pollutants: Experimental and computational studies

A series of AgVO3@ZIF(Zn, Co) samples were solvothermally prepared, and further evaluated as the photocatalysts for photodegradation of organic pollutants. The inherent characteristics of the as-synthesized composites were determined by some techniques such as XRD, SEM, TG-DTG, XPS, UV-Vis, ESR, and N2-adsorption. Interestingly, the component of the composite constructed with mass ratio of 3:1 (AgVO3@BZIF-3) showed the highest catalytic performance for the degradation of methylene blue (MB). This may be related to the formation of type II heterojunction between AgVO3 and bimetallic ZIF(Zn, Co), which results in MB molecules to be easily adsorbed and degraded on AgVO3@BZIF-3. The results of DFT calculations suggested that the newly-formed O-N bonds linking ZIF structure and AgVO3 crystal surface could promote the charge carriers through the heterostructure interface easily. Moreover, the highest photodegradation efficiency of MB was achieved with 98.20% when the reaction system was carried out at pH of 5, 3 h and 25 °C in the presence of photocatalyst mass of 30 mg. In addition, various substrates including methyl orange, indole, rofloxacin, methyl blue and tetracycline were respectively investigated under the optimal reaction conditions. Moreover, combined with ESR analysis and free radical capture experiments, superoxide radicals (·O2-) was confirmed as the key active species for organic pollutant photodegradation over AgVO3@BZIF-3.