The removal of antibiotics in environmental
water is of significant
importance due to their severe threats to human health and the ecosystem
balance but remains as a major challenge. Visible-light photocatalytic
degradation provides a desirable way to dispose of antibiotics by
natural solar energy. Herein, cadmium sulfide-doped polydopamine (CdS/PDA)
heteronanotubes (HNTs) featuring superior photocatalytic capability
for ultrafast antibiotic degradation under visible light (14.2 times
higher than traditional CdS) was developed via an in situ coordination
polymerization strategy. The exceptional catalytic ability was attributed
to multiple-level synergistic effects between PDA and CdS. PDA nanotubes
(NTs) served as a scaffold for in situ growth of CdS nanocrystals,
and the resulting CdS/PDA heterostructures exhibited strong visible-light-harvesting
capability and a high transfer rate of photogenerated electron–hole
pairs. Furthermore, the photocatalytic mechanism of the CdS/PDA HNTs
toward model molecule tetracycline is disclosed in detail, and it
is shown that superoxide radical anions (•O2–) and photogenerated holes (h+) play the key roles in the decomposition of tetracycline. Our findings
demonstrate that the incorporation of PDA NTs as the scaffold is a
feasible strategy to enhance the visible-light sensitivity of photocatalysts
used in aqueous antibiotic degradation. This work provides new insights
into the development of new functional nanocomposite catalysts with
important engineering and environmental applications.