Construction of immobilized CuS/TiO₂ nanobelts heterojunction photocatalyst for photocatalytic degradation of enrofloxacin: synthesis, characterization, influencing factors and mechanism insight

Abstract

BACKGROUND: Numerous antibiotics are consumed and excreted to the natural environment by humans and animals, which can cause considerable water pollution. There is strong demand to find an efficient and inexpensive photocatalyst to remove antibiotics effectively from contaminated water. RESULTS: Here, CuS/TiO 2 nanobelts (NBs) heterojunction photocatalyst immobilized on a titanium foil substrate was constructed. The morphology, structure, composition, optical, and electrochemistry characteristics were explored by corresponding characterization methods. The CuS/TiO 2 NBs exhibited enhanced photocatalytic activity for the photocatalytic degradation of antibiotic enrofloxacin (ENR) under simulated solar light illumination. The outstanding photocatalytic performance of as-prepared composite is attributed to not only the improvement of visible light harvest but also the enhanced separation and transfer efficiency of photoinduced charge carriers. Results showed that the presence of some anions produced a negative effect on the photocatalytic degradation of ENR. The photocatalytic degradation efficiency of ENR followed the order: no anion > Cl − = HCO 3 − > SO 4 2− > NO 3 − . The photocatalytic degradation of ENR was restrained in the presence of HA, however, the addition of hydrogen peroxide (0.05 mmol L −1 ) or application of extra electric field (1.5 V) resulted in an improvement in degradation of ENR. Active species trapping experiments confirmed that the superoxide radical (•O 2 − ) is the major oxidant species and the holes (h + ) and hydroxyl radical (•OH) are the minor active species. A possible heterojunction photocatalytic mechanism was proposed. Furthermore, CuS/TiO 2 NBs heterojunction photocatalyst has excellent photocatalysis stability. CONCLUSIONS: This novel visible-light responding CuS/TiO 2 NBs heterojunction photocatalyst would be a promising candidate material for antibiotic elimination from water.

Recent Achievements in Development of TiO2-Based Composite Photocatalytic Materials for Solar Driven Water Purification and Water Splitting

“…is excited and generates the e − /h + pair, where photogenerated e − in CB of CdS migrates to CB of TiO2 and is consumed in reactions with O2 to produce O2 •-, while h + remain in the VB of CdS. Copper sulfide (CuS), which is another metal sulfide semiconductor with narrow band gap of 2.0 eV, has also been reported to be coupled with TiO2 (Type II Heterojunction) [59,60]. Jiang et al [59] reported a 85.5% degradation of enrofloxacin and 27.7% mineralization of overall organic content using immobilized CuS/TiO2 nanobelts (Table 6).…”

“…Copper sulfide (CuS), which is another metal sulfide semiconductor with narrow band gap of 2.0 eV, has also been reported to be coupled with TiO 2 (Type II Heterojunction) [59,60]. Jiang et al [59] reported a 85.5% degradation of enrofloxacin and 27.7% mineralization of overall organic content using immobilized CuS/TiO 2 nanobelts (Table 6). They elucidated the mechanisms occurring in the composite upon excitation by solar irradiation.…”

Electrochemical Fingerprint of CuS-Hexagonal Chemistry from (Bis(N-1,4-Phenyl-N-(4-Morpholinedithiocarbamato) Copper(II) Complexes) as Photon Absorber in Quantum-Dot/Dye-Sensitised Solar Cells

“…Hexagonal covellite-CuS with a bandgap of ∼2 eV and a p-type-enhances absorber abilities to cover the entire solar spectrum [18,19]. Furthermore, CuS absorbs the infrared area through plasmonic absorption emanating from copper valencies due to a high concentration of charge carriers [20,26,27]. Integration of CuS with TiO 2 can enhance photon-absorption properties to visible regions, leading to better conversion efficiency.…”

Recent advances in two‐dimensional transition metal dichalcogenides as photoelectrocatalyst for hydrogen evolution reaction

“…99 However, the energy band alignment of TiO 2 is not suitable for efficiently producing hydrogen through photoreduction reaction. [100][101][102][103][104] On the contrary, the absorption of 2D-TMDs is weak; however, the band alignment is suitable for the redox potential of water. Therefore, the composites formed by 2D-TMDs with TiO 2 are expected to be promising catalysts for highperformance PEC-HER.…”