Calcium-doped bismuth oxybromide microspheres with enhanced photocatalytic degradation for ciprofloxacin under visible light

Rational design of efficient visible-light-responsive photocatalysts is pivotal for antibiotic degradation in aquatic environments. In this work, calcium-doped BiOBr (BOB) nanocomposites with controlled doping ratios were synthesized via a hydrothermal-calcination method and evaluated for ciprofloxacin (CIP) degradation under visible light. Experimental results demonstrate that the BiOBr/Ca-3 (BOB/Ca-3) sample exhibits a 1.64 times enhancement in CIP degradation efficiency compared to pristine BOB. Characterization data revealed that Ca doping optimizes the electronic and structural properties of BOB. Radical trapping experiments confirmed that •O 2 − and h + serve as the dominant reactive species. Cycling tests demonstrated the structural stability and recyclability of BOB/Ca-3. This study demonstrates that Ca-doped BOB modification proves to be an effective strategy for developing high-performance photocatalysts toward antibiotic-contaminated wastewater remediation.