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Hollow mesoporous TiO 2 spheres (THs) were prepared via template-directed deposition of TiO 2 nanoparticles on the surface of carbon spheres. The carbon spheres were used as hard templates. Their diameters were controlled by pH adjustment prior to a hydrothermal process. Physical properties, such as crystallinity, optical characteristics, microstructure and surface morphology of the samples were characterized. The results showed that the diameter of the carbon template could be well controlled in the range of 397–729 nm by adjusting the initial pH value of the dextrose solution from 3 to 10. Hollow TiO 2 spheres with average diameters ranging from 171 to 668 nm and shell thicknesses ranging from 28 to 47 nm formed by heat treatment at 450 °C. The photocatalytic performance of hollow TiO 2 spheres and TiO 2 nanoparticles was examined under UVA irradiation using a methyl orange aqueous solution as an artificial dye. The study revealed that the THs synthesized using a dextrose solution at pH 7 had a higher photocatalytic activity compared to other samples since it had the lowest shell thickness and the proper optical band gap of 3.12 eV with the longest lifetime of electron-hole pair separation. [ABSTRACT FROM AUTHOR]

A low-pressure capacitively coupled discharge was used to study antimicrobial treatment in herbal tea. Ambient air with a relative humidity of 40% was used as a precursor gas and fed into the chamber via a perforated power electrode. An electrical discharge plasma was produced at a radio frequency of 10 kHz and power of 80 W. The operating pressure during treatment was kept constant at 260 Pa. The target microorganisms, Escherichia coliand Staphylococcus aureus,isolated from the herbal tea were inoculated on nutrient agar petri dishes and exposed to the plasma for 0.5, 1.0, 1.5, and 2.0 min. All treatments were carried out in triplicate for different exposure times to calculate the D-value by the enumeration method. D-values of 0.73 and 0.67 min were obtained corresponding to E. coliand S. aureusreduction, respectively.

This work presents a novel route for utilizing waste from power plants to create a new power source (solar cells). Bottom ash (BA) ceramic micro-particles were studied to improve an electrocatalytic activity in solar cell applications for the first time. In the counter electrodes (CE) of dye-sensitized solar cells (DSSC), bottom ash was mixed with PEDOT:PSS (PP) and polyvinylpyrrolidone (PVP) (BA/PP/PVP) in volume ratios of 3:7, 4:6, 5:5, and 6:4. We found that bottom ash has a significant impact in improving the electrocatalytic activity and DSSC efficiency of these cells. Moreover, the PP and PVP ratios have a high impact on solar cell performance. The BA/PP/PVP-(6:4) counter electrode attained a higher DSSC efficiency, 2.70%, compared to the other electrodes prepared under similar conditions and a Pt CE based DSSC (3.23%) at AM 1.5 (100 mWcm−2). The influences of bottom ash and PP/PVP ratios on film structure, electrocatalytic activity in I3−reduction, redox reaction rate, and electron transport were characterized using SEM, CV, Tafel, and EIS, respectively. The results show that low-cost BA/PP/PVP-(6:4) CE is a promising new alternative to Pt CEs in DSSCs.