Synthesis of ZnO/Carbon Nanotube Composites for Enhanced Photocatalytic Performance and Its Mechanism Study

In this paper, zinc oxide (ZnO) nanotubes were synthesized via an anodic oxidation method, and ZnO/carbon nanotube (CNT) composites (ZnCNTs) were further fabricated through a hydrothermal method. The ZnCNT composites exhibited enhanced photodegradation efficiency for Rhodamine B (RhB) under simulated sunlight irradiation, with ZnCNT-5.7 (5.7 wt% CNTs) achieving 98.4% RhB degradation within 7.5 min. The apparent reaction rate constant ( k = 0.433 min− 1 ) was 4.84- and 3.46-folds higher than those of pristine ZnO and ZnCNT-1 (1 wt% CNTs), respectively. This superior photocatalytic performance originated from extended visible light absorption and improved charge carrier separation efficiency, which facilitated the utilization of photogenerated electrons (e − ) and holes (h + ). Radical trapping experiments confirmed that superoxide radicals (·O 2 − ) and hydroxyl radicals (·OH) were the dominant active species responsible for RhB degradation. This work provides a feasible strategy for designing efficient photocatalysts for dye-contaminated water treatment. Graphical ZnO/carbon nanotube (ZnCNT) composites demonstrate exceptional photocatalytic efficiency for rapid Rhodamine B degradation under simulated sunlight. The incorporated carbon nanotubes significantly enhance charge carrier separation and visible light absorption. This synergistic interaction promotes the generation of reactive oxygen species, enabling ultrafast dye removal and offering a promising strategy for environmental water purification.