Dual S-scheme V2O5/CdS/CdFe2O4 heterojunction for efficient visible-light-driven photocatalysis: Experimental and DFT insights

In photocatalysis, key challenges affecting pollutant degradation efficiency include charge recombination, limited light absorption, inadequate adsorption, and poor photocatalyst stability. In this work, a dual S-scheme V2O5/CdS/CdFe2O4 composite photocatalyst was successfully developed via a simple mixing approach, exhibiting enhanced light absorption, effective photocarriers separation, strong redox capability, and excellent stability. The V2O5 material is the major reason for the enhanced adsorption of V2O5/CdS/CdFe2O4 photocatalyst, whereas, narrow band gap of all the materials is responsible for enhanced visible light response. The energy gaps of V2O5, CdS, and CdFe2O4 photocatalysts were also calculated via density function theory (DFT). The calculated band gaps were in close agreement with the experimental values. The V2O5/CdS/CdFe2O4 exhibited dual S-scheme heterojunction which improve the charge separation, migration, and redox ability of photocatalyst. Compared to the pristine V2O5, CdS, and CdFe2O4 photocatalysts, V2O5/CdS/CdFe2O4 exhibited highest degradation efficiency for methylene blue (MB) dye. The V2O5/CdS/CdFe2O4 exhibited 93% degradation efficiency within 90 min towards MB dye under visible light exposure. Here, •OH and •O2− radicals were identified as the significant reactive radicals contributing in MB photodegradation. Therefore, dual S-scheme V2O5/CdS/CdFe2O4 heterojunction is an outstanding photocatalytic material towards textile dye removal because of its enhanced charge separation, adsorption ability and stability.