Facile synthesis of a novel WO3/Ag2MoO4 particles-on-plate staggered type II heterojunction with improved visible-light photocatalytic activity in removing environmental pollutants

Abstract

A novel WO₃/Ag₂MoO₄ heterojunction has been synthesized through a facile precipitation method with Ag₂MoO₄ particles firmly deposited on the surface of WO₃ nanoplates, forming “particles-on-plate” type II heterojunction structures. This heterojunction exhibited improved photocatalytic activities for the degradation of rhodamine B (RhB), 4 chlorophenol (4-CP) and tetracycline hydrochloride (TC) under visible-light irradiation compared to pure Ag₂MoO₄ and WO₃. In addition, the heterojunction with 10 wt% Ag₂MoO₄ displays the best photocatalytic performance, which was about 2 times better than that of pure WO₃ or Ag₂MoO₄. The TC photodegradation rate reaches up to 91% within 90 min visible light irradiation. Furthermore, the photocatalytic efficiency of the Ag₂MoO₄/WO₃ heterojunction is 1.3 times higher than that of the mixture of the two individual photocatalysts. This remarkable enhanced photocatalytic performance results from the staggered bandgap between Ag₂MoO₄ and WO₃, which can suppress the recombination of electron–hole pairs efficiently. Moreover, based on the radical trapping experiment, the superoxide radical anions (·OH) and photogenerated holes (h⁺) are the crucial active oxidizing species.