Construction of novel WO₃/SnNb₂O₆ hybrid nanosheet heterojunctions as efficient Z-scheme photocatalysts for pollutant degradation

The artificially Z-scheme heterojunctions between WO₃ nanosheet and SnNb₂O₆ nanosheet with strongly coupled heterointerfaces were successfully constructed via a simple hydrothermal coassembly method. Transmission electron microscopy (TEM) and high-resolution TEM proved that an intimate contact interface was formed. The synthesized heterojunctions exhibites enhanced photodegradation efficiency for Rhodamine B under irradiation of visible light, and the highest reaction rate over 30%-WO₃/SnNb₂O₆ nanosheet heterojunctions is about 4.7-fold and 2-fold higher than that of pristine WO₃ and SnNb₂O₆, respectively. Such a considerable improvement could be mainly attributed to the rapid migration of the photo-induced e^-/h⁺ pairs through the nanosheets-coupled heterojunction interfaces. A possible directly Z-scheme charge transfer mechanism was proposed for the elimination of organic contaminants under irradiation of visible light. This work may furnish new insights into development of novel 2D/2D nanosheet heterojunctions with the enhanced photocatalytic activity.