Fabrication of heterostructured CdS/TiO2 nanotube arrays composites for photoreduction of U(VI) under visible light

Heterostructured CdS/TiO2 nanotube arrays composites (CdS/TNTAs) were synthesized by the successive ionic layer adsorption (SILAR) reaction with vacuum freeze-drying-assisted method. The CdS nanoparticles were anchored on the inner wall of the anodic TNTAs via strong electronic interaction rather than occupied the nanotubes. The CdS/TNTAs-10 with 27.28 wt% CdS exhibited shows the best photocatalytic activity for reduction of U(VI) (97% at 240 min) and the photocatalytic activity was still 83.6% after 5 cycles. These improvements probably stem from the porous tubular structure of TNTAs acts as the protective shell which can effectively inhibit the photocorrosion of CdS and promote the photoinduced interfacial electron-hole pairs separation. Furthermore, the possible the photocatalytic electron transfer path was proposed, and the photogenerated electrons (e) and the superoxide radicals (center dot O-2(-)) were the predominant active free radicals. This work highlighted a simple synthesis of CdS/TNTAs heterojunction with potential application in radioactive wastewater remediation.

Automated summary

CdS/TiO2 heterostructured nanotube arrays composites were successfully synthesized via the SILAR reaction with vacuum freeze-drying-assisted method. The CdS nanoparticles anchored on the TiO2 nanotubes showed excellent photocatalytic activity, achieving a 97% reduction efficiency of U(VI). The unique structure of the composite material not only effectively inhibited photocorrosion, but also promoted the separation of photoinduced electron-hole pairs.