Boosted degradation of tetracycline over a novel Z-scheme DyVO4/MIL-53(Fe) heterojunction with surface oxygen vacancy under visible light irradiation

Abstract

The construction of heterojunction and surface defect engineering are attractive methods for the improvement of the photocatalytic performance of the semiconductors. Herein, a novel Z-scheme heterojunction DyVO4/MIL-53(Fe) composed of DyVO4 with oxygen vacancies (OVs) and MIL-53(Fe) was for the first time fabricated by a facile solvothermal method. The prepared photocatalyst were characterized by a variety of techniques. The photocatalytic activity was assessed by the photodegradation of tetracycline (TC) under visible light irradiation. The characterization results shows that DyVO4/MIL-53(Fe) exhibits excellent visible light response. The introduction of OVs on the surface of DyVO4 accelerated the separation of photogenerated carriers. Furthermore, OVs and Z-scheme hetero constructure showed synergism in promoting the transfer and separation of the photoinduced charge carriers. The prepared DyVO4/MIL-53(Fe) has excellent photocatalytic performance for TC degradation. At pH of 5, the degradation efficiency of TC over the optimum composite DM30 (30 wt% DyVO4/MIL-53(Fe)) is up to 98.2%, and TOC removal rate is 46.2%. The hydroxyl radical (•OH), superoxide radicals (•O2−), and holes (h+) were all found to act as main active species in TC photodegradation. The enhanced photocatalytic activity is attributed to the excellent visible light response and the obviously promoted transfer and separation of the photogenerated electrons and holes.