Visible light assisted photocatalytic performance of Europium doped ZnS-Nb2O5 heterostructure for mineralization of Acid violet 7 dye

Schematic representation of photogenerated charge transfer process in Europium doped ZnS-Nb2O5 heterostructure. [Display omitted] •3Eu50ZN catalysts with defects levels/surface states for mineralization of AV7 dye.•Visible light absorption with prominent redshift for 3Eu50ZN heterostructure.•Superior capacitance, enhanced charge carrier separation with improved stability.•Combined effect of reduced band gap, enhanced charge separation and surface area. The present study focuses on the visible light assisted photocatalytic performance of Europium doped ZnS-Nb2O5 heterostructure catalysts for the mineralization of organic pollutants such as Acid violet 7 (AV7) dye. Structural and morphological investigations reveal the presence of wurtzite ZnS and Nb2O5 components in the prepared heterostructure in separate phases. The prepared Europium doped ZnS-Nb2O5 (3Eu50ZN) heterostructures shows enhanced visible light absorption with prominent redshift. Photoluminescence study suggests the presence of surface states/defect energy levels in Europium doped ZnS-Nb2O5 heterostructure catalysts. In comparison to doped and undoped components, the fluorescence lifetime analysis demonstrates enhanced charge separation in 3Eu50ZN heterostructure catalysts. Photo/electrochemical studies reveal superior capacitance behavior, enhanced charge carrier separation, and improved stability in the aqueous phase for 3Eu50ZN heterostructure in comparison to ZnS and Nb2O5 catalysts. The superior visible light assisted photocatalytic performance with 3Eu50ZN heterostructure catalysts was achieved for the mineralization of AV7 dye (20 mg L−1). Active species determination suggests photogenerated holes (h+) to be the major active species responsible for the degradation reaction and a plausible reaction pathway was proposed. The 3Eu50ZN heterostructure catalysts exhibit a recycling nature and demonstrate improved stability.