Heterojunction Engineering of CdS Nanospheres and Rice‐Like Brookite TiO 2 for High‐Efficiency Visible‐Light Photocatalytic Removal of Ciprofloxacin Hydrochloride

ABSTRACT The pervasive application of antibiotics has resulted in substantial contamination of aquatic ecosystems, necessitating the implementation of effective antibiotic wastewater treatment. We reported synthesizing highly crystalline rice‐like brookite TiO 2 via hydrothermal synthesis. Based on this, CdS/brookite TiO 2 heterojunction composites with varied molar ratios were made via the same protocol using Cd(CH 3 COO) 2 ·2H 2 O as precursor. SEM characterization revealed that the synthesized brookite exhibited a rice‐shaped morphology with a smooth surface, measuring approximately 200 nm in length. In contrast, CdS displayed spherical nanostructures with an average diameter of 500 nm. DRS analysis further demonstrated that the incorporation of CdS into the composite substantially narrowed the band gap of brookite. A systematic investigation into the visible‐light‐driven photocatalytic degradation of ciprofloxacin (CIP) hydrochloride was conducted utilizing the synthesized composite materials. The experimental results revealed that the CdS/brookite TiO 2 composite with 20 mol% CdS loading demonstrated superior degradation efficiency compared to pristine brookite TiO 2 . The composite demonstrated a degradation efficiency of 73% after five consecutive cycles. The marked improvement in performance was primarily due to the formation of a heterojunction structure between the two integrated materials. This work contributed valuable theoretical insights for the design and application of efficient photocatalytic systems targeting CIP‐contaminated wastewater.