Influence of Size and Shape on the Photocatalytic Properties of SnO₂ Nanocrystals

Abstract

Tuning the functional properties of nanocrystals is an important issue in nanoscience. Here, we are able to tune the photocatalytic properties of SnO2 nanocrystals by controlling their size and shape. A structural analysis was carried out by using X-ray diffraction (XRD)/Rietveld and transmission electron microscopy (TEM). The results reveal that the number of oxygen-related defects varies upon changing the size and shape of the nanocrystals, which eventually influences their photocatalytic properties. Time-resolved spectroscopic studies of the carrier relaxation dynamics of the SnO2 nanocrystals further confirm that the electron-hole recombination process is controlled by oxygen/defect states, which can be tuned by changing the shape and size of the materials. The degradation of dyes (90%) in the presence of SnO2 nanoparticles under UV light is comparable to that (88%) in the presence of standard TiO2 Degussa P-25 (P25) powders. The photocatalytic activity of the nanoparticles is significantly higher than those of nanorods and nanospheres because the effective charge separation in the SnO2 nanoparticles is controlled by defect states leading to enhanced photocatalytic properties. The size- and shape-dependent photocatalytic properties of SnO2 nanocrystals make these materials interesting candidates for photocatalytic applications.

Controlled synthesis of Sn-based oxides via a hydrothermal method and their visible light photocatalytic performances

“…Due to its high optical transparency in the visible range, the remarkable receptivity to variation of gas, the low resistivity, and the excellent chemical stability, SnO 2 has been extensively used in transparent conductive electrodes, 4 gas sensors, 10,11 Li-batteries, 5 sensitized solar cells, 12 and photocatalysts. [13][14][15] To optimize the SnO and SnO 2 performances, various preparation methods including sol-gel, precipitation, hydrothermal, solvothermal, thermal evaporation, electrospinning, and laser ablation have been developed to manipulate their sizes, structures, and morphologes. 8 Taking SnO 2 as an example, the particle size can be reduced through a surfactantassisted solvothermal 16 or hydrothermal 17,18 route, while as for the morphologies, 0 to 3 dimensional SnO 2 nanostructures, such as nanoparticles, nanorods, nanowires, nanotube, nanosheets, and the 3D hierarchical architectures self-assembled from these low-dimensional nanostructures, have been subtly fabricated.…”

Upconversion Nanoplatform for FRET‐Based Sensing of Dopamine and pH

“…Additionally, the absorption bands at 940 cm -1 and 1070 cm -1 can be assigned to Si-OÀ Si bonds and SiÀ O bonds, respectively. Apart from serving to avoid the surface-mediated quenching of UC emission, [21] the high surface area and porous channels of MS layer are expected to facilitate the entry of DA molecules inside the pores, thereby allowing FRET to take place between oxidized DA (q-DA) and the emission in the blue region from BCSU-MS. The MS functionality also imparts biocompatibility to the nanoplatform.…”

Realization of Visible Light Photocatalysis by Wide Band Gap Pure SnO2 and Study of In2O3 Sensitization Porous SnO2 Photolysis Catalyst

“…[8][9][10] But, SnO 2 is a n-type wide band gap semiconductor (Eg = 3.6 eV) which has only responsive to high-energy ultraviolet light. [30,31] As we all know that the fraction of ultraviolet light only accounts for 4% of total solar spectrum on the earth, which limits the practical application of SnO 2 in visible light region. The exploition of SnO 2 -based visible light photocatalysts has become an important subject.…”