Investigating the influence of p-n and Z-scheme mechanisms on the photocatalytic characteristics of CuBi2O4/V2O5/MWCNT and its efficiency in the mitigation of organic pollutants

Abstract

The charge transportation and light utilization in the single mechanism or conventional heterojunction systems are still considered a big challenge. Herein, a novel ternary CuBi₂O₄/V₂O₅/multi-walled carbon nanotubes (MWCNTs) heterojunction with a multi-function mechanism coupled between p-n and Z-scheme charge transfer routes was successfully proposed. The phase purity and chemical group of CuBi₂O₄/V₂O₅/MWCNT was demonstrated by XRD and FT-IR. The morphological analysis of ternary sample manifested a well-integrated spherical cluster of CuBi₂O₄/V₂O₅ with MWCNT, improving the texture and structure stability of composites. The ternary integration significantly boosted the surface area of CuBi₂O₄/V₂O₅/MWCNT (37.471 m²/g) compared to CuBi₂O₄ (15.679 m²/g) and V₂O₅ (16.313 m²/g). Moreover, the synergistic interaction between the narrow-bandgap semiconductor (CuBi₂O₄) and MWCNTs significantly improves the electronic conductivity and light-harvesting efficiency of the CuBi₂O₄/V₂O₅/MWCNT composite. Under 40 W LED irradiation, our heterojunction achieved powerful photoactivity of 97.5 %, 80.3 %, and 92.7 % towards Congo red (CR), methylene blue (MB), and tetracycline (TC), signifying the robust efforts of the composite to mitigate both color and colorless pollutants. The catalytic mechanism suggested the synergistic work between the p-n junction and Z-scheme charge dynamics. Further, MWCNTs assist as a perfect electron conductor to channel the charge carriers between p-CuBi₂O₄ and n-V₂O₅, accelerating the separation of photocarriers and delaying their reintegration. Our work seeks to raise the effectiveness of photocatalysis over multi-mechanistic approaches, mitigating environmental pollution through economic and sustainable energy.