Effect of pH on photocatalytic activity of SnO₂ microspheres via microwave solvothermal route

Abstract

Quasi-monodispersed SnO 2 microspheres have been successfully synthesised by a microwave solvothermal method, in which polyethylene glycol is used as template, SnCl 4 .5H 2 O and urea as raw materials. The products have been characterised by X-ray diffraction, a scanning electron microscope, and a transmission electron microscope. Besides, the thermal behaviour of the products synthesised by solvothermal process has been studied through the thermogravimetry differential scanning calorimetry. Photocatalytic activities of the samples have been evaluated by the degradation of rhodamine B (RhB) in different pH values under UV light illumination. Results showed that these microspheres with diameter about 1?0-1?5 mm were composed of numerous SnO 2 nanoparticles with a diameter of y9 nm. The SnO 2 microspheres exhibited a high effective adsorption and an excellent photocatalystic activity of RhB in a wide range of pH values.

Conversion of “Waste Plastic” into Photocatalytic Nanofoams for Environmental Remediation

“…Additionally, the porous channel structure may facilitate better transport of contaminant molecules to reach catalytically active sites 55 . Reaction kinetics analyses reinforce that incorporation of the SnO 2 nanoparticles into the PS foams improves RhB photodegradation, with rate constants as high as 0.054 min -1 , being similar/higher than other reported systems, which are sometimes chemically more complex than these nanofoams 48,51,52…”

“…Considering that the radiation source used has constant flux, and the number of photocatalyst active sites is solely dependent on the surface area, pseudo first-order kinetics are expected, provided there is no catalyst poisoning during the process. According to 48 these results may be associated with N-de-ethylation of RhB, since, as shown in Fig. 8, N-de-ethylation cannot be totally avoided and will occur in parallel with the direct degradation pathway.…”

“…Note that is not easy to compare these results, since besides RhB:SnO 2 molar ratio, irradiation power is an important factor, and the 60 W lamp used here is smaller than some others reported, such as 300 W for the work of Zhu et. al 48 . The first run showed 98.3% of RhB degradation; cycle 2, 98.3%; cycle 3 showed 97.8% degradation; cycle 4, 96.5% and the fifth degraded 82% of the initial dye.…”

Cation-containing active carbons as photocatalysts for dyes degradation

“…This may be due to the fact that RhB molecules absorb light photons and their excitation is possible [35,36]. On the other hand, it is well known that photocatalytic degradation of RhB can occur by two pathways [36,37]: as de-ethylation process in a stepwise manner (with the formation of the three intermediates from RhB to сompletely de-ethylated Rh110) or as a direct cleavage of the chromophore rings. The gradual blue shift in λmax of the spectrum of RhB is observed in the first case and the reduction in the absorbance without shift takes place in the second case.…”

Enhanced UV–Vis photocatalytic performance of the CuInS 2 /TiO 2 /SnO 2 hetero-structure for air decontamination

“…The use of different mono-component photocatalyst such as TiO 2 [7][8][9], ZnO [10,11], SnO 2 [12,13] or WO 3 [14,15] demonstrated the feasibility of using a semiconductor to reduce the air pollutants content. Although efficient, these materials have limited response under Vis/solar irradiation, with negative consequences considering sustainability (energy consumption) and the overall cost of the photocatalytic process.…”