Synergistic Photocatalytic Amplification of Rhodamine B Degradation by Ratiometric Optimization of BiOCl/Cr 2 O 3 Heterostructure

ABSTRACT Efficient removal of organic dyes from industrial and domestic effluents is essential for potable water reclamation. Rhodamine B (RhB) is one such dye used extensively in textile, paper, and food industries, having adverse health effects. Heterostructured photocatalysts are deemed to be an effective and affordable solution, while compatibility, stability, and performance are the key challenges. Our approach introduces a BiOCl/Cr 2 O 3 nanocomposite with various BiOCl compositions (10, 15, 20 wt% with respect to Cr 2 O 3 ) as a sustainable photocatalyst for RhB degradation. Enriching BiOCl content improves light absorption, reduces band gap, and minimizes electron‐hole pair recombination. Photocatalytic performance optimization reveals a 99.7% RhB degradation within 75 min at pH 7 using 20 mg of 20 wt% BiOCl/Cr 2 O 3 , significantly outperforming pure BiOCl (61.32%) and Cr 2 O 3 (54.75% RhB degradation) under identical conditions. Kinetic analyses confirm fivefold higher degradation rates of 20 wt% BiOCl/Cr 2 O 3 compared to starting materials. Radical scavenging experiments alludes to hydroxyl radical mediated dye decomposition pathways. This work establishes rational optimization of sustainable composite photocatalysts for cooperative strengthening towards wastewater dye decontamination.