Conjugated polymers S-scheme homojunction with large internal electric field and matching interface for efficient visible light photocatalytic degradation of ciprofloxacin

Abstract

Given the urgent demand and broad prospects for renewable energy and sustainable environmental technologies, the semiconductor-based photocatalysis represents an increasingly attractive frontline technique. Herein, a conjugated polymers S-scheme homojunction was prepared by electrostatic self-assembling the hollow tubular g-C3N4 (PCN) and nitrogen deficient boron doped g-C3N4 nanosheets (BCNx). The photocatalytic removal of the typical antibiotic ciprofloxacin (CIP) was conducted to verify the performance of PCN/BCNx. The pathway of S-scheme charge transfer was validated through the techniques, such as DFT calculations and Kelvin probe force microscope. The PCN/BCNx S-scheme homojunction features the efficient separation of carriers without compromise their redox potentials. The internal electric field (IEF) intensity of PCN/BCN3 was 2.34 times that of PCN and 1.40 times that of BCN3. Given the credit to the unique S-scheme carriers transfer route and the enhanced IEF intensity, under visible light illumination, the tallest CIP degradation percentage (94.9%) was gained in PCN/BCN3. The rate constants (0.0251 min−1) were 2.1 times that of BCN3 and 3.8 times that of PCN, respectively. Furthermore, the reactive oxygen species for CIP degradation was clarified based on chemical trapping experiment and ESR results. The conjugated polymers S-scheme homojunction with large IEF and matching interface was synthesized in the current study for treating antibiotics polluted waters.