Uniformly dispersed CdS/CdSe quantum dots co-sensitized TiO2 nanotube arrays with high photocatalytic property under visible light

• Detached TiO2 nanotube arrays with large space between tubes were fabricated.
• CdS and CdSe QDs were uniformly co-deposited on both outer and inner tubes.
• The catalyst showed high photocatalytic activity and stability under visible light.

Highly detached TiO2 nanotube arrays (TiO2-NTAs) were fabricated by anodization method using electrolyte with high water content. CdS and CdSe quantum dots (QDs) were co-deposited on the TiO2-NTAs. The results showed that the CdS and CdSe QDs were uniformly deposited on both the outer wall and inner tube of TiO2-NTAs. The photocatalytic performance of the as-prepared (CdS–CdSe)/TiO2-NTAs was tested by degradation of methyl orange with 0.2 M Na2S and Na2SO3 as sacrificial reagents under visible light (λ>400 nm). It was found that the photodegradation rate reached as high as 95.1% in 2 h. Also, a reasonable degradation rate of 87.5% was achieved after 3 cycles, suggesting a good stability of the as-prepared (CdS–CdSe)/TiO2-NTAs.

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