Hierarchical assembly of ultrathin hexagonal SnS₂nanosheets onto electrospun TiO₂nanofibers: enhanced photocatalytic activity based on photoinduced interfacial charge transfer

Abstract

Well-designed hierarchical nanostructures with one dimensional (1D) TiO(2) nanofibers (120-350 nm in diameter and several micrometers in length) and ultrathin hexagonal SnS(2) nanosheets (40-70 nm in lateral size and 4-8 nm in thickness) were successfully synthesized by combining the electrospinning technique (for TiO(2) nanofibers) and a hydrothermal growth method (for SnS(2) nanosheets). The single-crystalline SnS(2) nanosheets with a 2D layered structure were uniformly grown onto the electrospun TiO(2) nanofibers consisted of either anatase (A) phase or anatase-rutile (AR) mixed phase TiO(2) nanoparticles. The definite heterojunction interface between SnS(2) nanosheets and TiO(2) (A or R) nanoparticles were investigated by high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). Moreover, the as-prepared SnS(2)/TiO(2) hierarchical nanostructures as nanoheterojunction photocatalysts exhibited excellent UV and visible light photocatalytic activities for the degradation of organic dyes (rhodamine B and methyl orange) and phenols (4-nitrophenol), remarkably superior to the TiO(2) nanofibers and the SnS(2) nanosheets, mainly owing to the photoinduced interfacial charge transfer based on the photosynergistic effect of the SnS(2)/TiO(2) heterojunction. Significantly, the SnS(2)/TiO(2) (AR) hierarchical nanostructures as the tricomponent heterojunction system possessed stronger photocatalytic activity than the bicomponent heterojunction system of SnS(2)/TiO(2) (A) hierarchical nanostructures or TiO(2) (AR) nanofibers, which was discussed in terms of the three-way photosynergistic effect between SnS(2), TiO(2) (A) and TiO(2) (R) component in the SnS(2)/TiO(2) (AR) heterojunction resulting in the high separation efficiency of photoinduced electron-hole pairs, as evidenced by photoluminescence (PL) and surface photovoltage spectra (SPS).

Synthesis of rare earth doped TiO2nanorods as photocatalysts for lignin degradation

“…In order to enhance the interfacial charge-transfer efficiency and utilize a wider spectral range of solar energy, the TiO 2 catalyst has been modified by ion doping 19,20 and manipulating the nanomaterial composition. 21,22 Rare earth (RE) ion dopants, such as Ce, 23 La, 24 Er 25 and Pr, 26 have shown unique enhancement effects, resulting from the orbital hybridization of 4f electrons. Positive effects of 4f electron orbital hybridization on the photocatalytic activities of TiO 2 were reported previously.…”

A novel scheme to obtain tunable fluorescent colors based on electrospun composite nanofibers

“…Electrospinning is an outstanding technique to process viscous solutions or melts into continuous composite fibers or belts with 1D nanostructure [20][21][22]. It can manufacture composite fibers with diameters ranging from micrometer to submicron or nanometer.…”

BiOCl/SnS2 Core-Shell Photocatalyst for the Degradation of Organic Pollutants

“…The match degree of interfacial lattice is an important factor to be concerned in the growth of material. 22 The lattice mismatch will prevent the nucleation and growth of an overlayer on the substrate due to the high structural strain. 30,31 The match degree between BiOCl and SnS 2 is investigated in detail by HRTEM at the interface.…”

“…21 Doping the narrow band gap n-type SnS 2 with a wide band gap p-type semiconductor is an e®ective way to solve this problem. 22,23 BiOCl has been widely studied for water splitting and organic pollutants degradation under UV light irradiation. 23,24 However, the wide band gap of BiOCl con¯nes its application in visible light region.…”