Xianbao Duan

Visible-light-driven photocatalytic and photoelectrochemical properties of porous SnSx(x = 1,2) architectures

By using a facile and template-free polyol refluxing process, we reported the successful synthesis of porous SnS and SnS2 architectures on a large scale. The as-synthesized samples were characterized by using XRD, SEM, TEM, UV-vis DRS, Raman and N2 adsorption–desorption analyses. Studies revealed that the as-synthesized SnS and SnS2 products mainly consist of porous flower-like microstructures with reasonable BET surface areas of 66 m2 g−1 and 33 m2 g−1, respectively. Photocatalytic properties of trace amounts of samples were investigated by photodegradation of MB and RhB under visible light irradiation. The photoelectrochemical properties of both samples were also studied by configuring the samples as photoelectrochemical (PEC) cells, exhibiting excellent photosensitivity and response with greatly enhanced Ion/off as high as 1.4 × 103, three orders of magnitude higher than previous work. The results indicate the potential applications of the SnSx nanostructures in visible-light-driven photocatalysts, high response photodetectors and other optoelectronic nanodevices.

Investigation of band offsets of interface BiOCl:Bi2WO6: a first-principles study

Density functional theory calculations are performed to study the band offsets at the interface of two photocatalytic materials BiOCl:Bi(2)WO(6). It is found that the W-O bonded interface shows the most stability. An intrinsic interface fails to enhance the charge-carrier separation due to the improper band alignment between these two materials. Sulfur (S) is proposed to replace the bulk oxygen (O) site and thus tune the band edges of BiOCl to enhance the photocatalytic performance of the heterojunction. Furthermore, the presence of S provides an extra charge to generate a clean interface with minimal gap states that also benefits carrier migration across the heterojunction.

First-principles study of the structural, energetic and electronic properties of C20-carbon nanobuds

The structural, energetic and electronic properties of carbon nanobuds (CNBs) with the smallest fullerene C20 covalently attached to the sidewall of single-walled carbon nanotubes (SWNTs) are studied by first-principles calculations. Due to the high curvature of C20 and the resulting chemical activity, the binding between C20 and SWNTs is quite strong. Among different CNB configurations, bond cycloaddition is energetically most favorable. The activation barrier for C20–CNB formation is only one-fourth that of C60 and it would maintain good stability once formed. Our results also reveal that C20–CNB stability depends on the chirality of the SWNTs, and they exhibit tunable band gaps that can be modulated by the density of C20 attached to the SWNTs.