Improved photocatalytic performance of CdS/α-Fe2O3 heterostructure for anionic dye mineralization and charge storage applications

[Display omitted] •The visible light-assisted photocatalytic performance of CdS/α-Fe2O3 heterostructure catalysts is explored for AV7 dye mineralization and charge storage applications.•The improved photocatalytic performance was achieved due to the interactive effect of visible light absorption, increased surface area, and an enhanced lifetime of photogenerated charge carriers.•The optimized 85CF heterostructure electrode shows improved specific capacitance of 938 F/g at 1.0 A/g of current density.•The greater capacity retention of 99.02% was achieved with the 85CF heterostructure after 2000 continuous charge/discharge cycles. The present work focuses on the photocatalytic mineralization of Acid violet 7 (AV7) dye with visible light assistance and the electrochemical functionality of synthesized CdS/α-Fe2O3 (85CF) heterostructure for energy storage applications. The prepared CdS/α-Fe2O3 heterostructure shows enhanced absorption of visible light compared to pristine CdS. Photoluminescence (PL), fluorescence lifetime, and electrochemical studies suggest improved charge separation in the optimized 85CF heterostructure catalysts compared to pure components. Electrochemical studies reveal improved capacitance, reduced charge transfer resistance, and superior charge–discharge behavior in optimized 85CF heterostructure catalysts compared to pristine components and other prepared composites. The improved photocatalytic activity was achieved by 85CF heterostructure catalysts for a higher concentration of AV7 dye (85 mg L−1) degradation. The major reactive oxygen species (ROS) were investigated, and a possible reaction pathway was presented. TOC analysis suggests mineralization occurs during the degradation reaction. The optimized 85CF heterostructure shows a higher specific capacitance of 938 F/g at 1.0 A/g of current density. A greater capacity retention of 99.02% was achieved with the 85CF heterostructure after 2000 continuous charge/discharge cycles.