p-n ZnCr2O4/Bi2O3 heterojunction as an effective photocatalytic degradation of MB and CIP

Photocatalysis is a potentially effective method for organic pollutant degradation, and the development of rationally engineered heterojunction photocatalysts has proven to be a promising solution. The present study investigated the eco-friendly photocatalysts ZnCr2O4 (ZCO), Bi2O3 (BO), and ZnCr2O4/Bi2O3 (BZ) heterojunction for the efficient photocatalytic degradation of an industrial dye Methylene Blue (MB) and a medical antibiotic Ciprofloxacin (CIP). BZ heterojunctions were synthesized using different weight percentages of BO (2 % (2BZ), 4 % (4BZ), and 6 % (6BZ) as photocatalysts through an in-situ hydrothermal method followed by calcination. The XPS assessment confirms that the 4BZ sample has increased its surface oxygen vacancy from 23 % to 49 %. The formation of p-n junction-induced internal electric field (IEF) facilitates the effective degradation towards the MB and CIP with the efficiency of 99 % (k = 0.05548 min−1) and 60 % (k = 0.01307 min−1) in 50 min. This result is 1.57 times higher than that of pristine ZCO for MB degradation and 1.59 times higher for CIP degradation. This investigation provides a promising approach with feasible applications in the degradation of MB dye and CIP antibiotics from aqueous solutions. Further, the photocatalytic mechanism demonstrates how heterojunction transport charge carriers, preventing electron-hole pair recombination and enhancing photocatalytic performance.