Qinqin Zhao

Morphology-modulation of SnO2 Hierarchical Architectures by Zn Doping for Glycol Gas Sensing and Photocatalytic Applications.

The morphology of SnO2 nanospheres was transformed into ultrathin nanosheets assembled architectures after Zn doping by one-step hydrothermal route. The as-prepared samples were characterized in detail by various analytical techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and nitrogen adsorption-desorption technique. The Zn-doped SnO2 nanostructures proved to be the efficient gas sensing materials for a series of flammable and explosive gases detection, and photocatalysts for the degradation of methyl orange (MO) under UV irradiation. It was observed that both of the undoped and Zn-doped SnO2 after calcination exhibited tremendous gas sensing performance toward glycol. The response (S = Ra/Rg) of Zn-doped SnO2 can reach to 90 when the glycol concentration is 100 ppm, which is about 2 times and 3 times higher than that of undoped SnO2 sensor with and without calcinations, respectively. The result of photocatalytic activities demonstrated that MO dye was almost completely degraded (~92%) by Zn-doped SnO2 in 150 min, which is higher than that of others (MO without photocatalyst was 23%, undoped SnO2 without and with calcination were 55% and 75%, respectively).

Controlled assembly of Bi2S3 architectures as Schottky diode, supercapacitor electrodes and highly efficient photocatalysts

Bismuth sulfide (Bi2S3) microflowers have been successfully fabricated through a one-pot hydrothermal method. The structures and morphologies of the as-obtained products are characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Raman spectroscopy. The experimental results show that Bi2S3 microflowers are composed of many microrods with lengths of 18–20 μm. Metal/semiconductor/metal (MSM) sandwich structures are fabricated, and the current–voltage (I–V) characteristics exhibit a clear back-to-back Schottky-diode behavior. The galvanostatic charge–discharge performance illustrates that the prepared Bi2S3 microflowers exhibit good performance for discharge efficiency at current densities from 1 mA cm−2 to 10 mA cm−2. Furthermore, the as-synthesized Bi2S3 microflowers are also used as the efficient UV-light photocatalysts for the photocatalytic degradation of methylene orange (MO) under light illumination, which shows almost complete degradation (∼95%) of MO dye.

Effects of architectures and H2O2 additions on the photocatalytic performance of hierarchical Cu2O nanostructures

Cu2O hierarchical nanostructures with different morphologies were successfully synthesized by a solvothermal method using copper (II) nitrate trihydrate (Cu(NO3)2⋅3H2O) and ethylene glycol (EG) as initial reagents. The obtained nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) specific surface area test, and UV-vis spectroscopy. The synthesis conditions (copper source, temperature, and reaction time) dominated the compositions and the formation of crystals with different morphologies. The visible light photocatalytic properties of as-prepared Cu2O nanostructures were investigated with and without hydrogen peroxide (H2O2), and the effect of H2O2 were evaluated by monitoring the degradation of methyl orange (MO) with various amounts of H2O2. It was revealed that the degree of the photodegradation of MO depends on the amount of H2O2 and the morphology of Cu2O.

One-pot synthesis of Zn-doped SnO2 nanosheet-based hierarchical architectures as a glycol gas sensor and photocatalyst

Zn-doped SnO2 hierarchical architectures (ZSHAs) with controllable size have been prepared using a facile hydrothermal method, which are composed of two dimensional (2D) nanosheets with a thickness of about 40 nm. The properties of ZSHAs have been explored by gas sensing and photocatalysis testing. A sensor response (S = Ra/Rg) of 43 can be achieved at 100 ppm glycol, and the detection limit can reach down to the 5 ppm level with a response of about 5, combined with a low operating temperature of 240 °C, suggesting a promising application of ZSHAs in glycol gas sensing. Besides, the photocatalytic activities of ZSHAs have been evaluated by the degradation measurement of methylene blue (MB), methylene orange (MO), and rhodamine B (RhB). As a result, the ZSHAs demonstrate a much higher selectivity on the degradation of MB (91%) than that of MO (40%) and RhB (60%) in 60 min of measurement.

SnO 2 -based nanomaterials: synthesis and application in lithium-ion batteries and supercapacitors

Tin dioxide (SnO2) is an important n-type wide-bandgap semiconductor, and SnO2-based nanostructures are presenting themselves as one of the most important classes due to their various tunable physicochemical properties. In this paper, we firstly outline the syntheses of phase-pure SnO2 hierarchical structures with different morphologies such as nanorods, nanosheets, and nanospheres, as well as their modifications by doping and compositing with other materials.Then, we reviewed the design of SnO2- based nanostructures with improved performance in the areas of lithium-ion batteries (LIBs) and supercapacitors.