Photocatalysis has been applied to decompose the waste and toxic materials produced in daily life and in the global environment. Pure TiO 2 (Zn-TiO 2 -0) and Zn-doped TiO 2 (Zn-TiO 2 -x, x = 3-10 mol %) samples were synthesized using a novel sol-gel and ammonia-evaporation method. The Zn-doped TiO 2 samples showed high photocatalytic activity for the degradation of methylene blue (MB). The physicochemical properties of the samples were investigated using XRD, SEM, ICP, DLS and BET methods. In addition, the most important measurement of photocatalytic ability was investigated by a UV-vis spectrophotometer. The effects of the mol % of zinc ion doping in TiO 2 on photocatalytic activity were studied. Among the mol % Zn ions investigated, the Zn-TiO 2 -9 sample showed the highest photoreactivity. This sample removed 91.4% of the MB after 4 h, while the pure TiO 2 only removed 46.4% of the MB.

A direct current (DC) operating voltage and luminescence property of red electroluminescent (EL) devices with and/or without a silicon dioxide (SiO2) layer at interface between nanocrystalline Si (nc-Si) region and Si substrate has investigated. The removal of SiO2 layer in the EL device led to the lowering of DC operating voltage from 4.0 up to 2.0 V and the increase of luminescence intensity more than one order of magnitude. The external quantum efficiency of red luminescence from the EL device without the SiO2 layer at the DC operating voltage of 3.0 V was 0.5%. These were realized by the efficient and easy injection of carriers to the radiative recombination centers in the nc-Si region due to the removal of SiO2 layer. These results indicate that the removal of SiO2 layer is drastically improved the DC operating voltage and luminescence intensity for the nc-Si based EL device.

PEMFC (Polymer Electrolyte Membrane Fuel Cell) is widely considered as an energy conversion system from the chemical energy of hydrogen to electric energy. But, hydrogen fuel obtained from hydrocarbons has trace amount of carbon monoxide which is a potential poison for platinum electrode at the cell operating temperature ∼100 °C and it becomes a huddle for the general usage of PEMFC. On the other hand PAFC (Phosphoric Acid Fuel Cell) operates at a higher temperature and the platinum electrode oxidizes carbon monoxide poison while there is a leakage problem of the liquid phase. To combine the advantages of two fuel cells, the electrolyte systems of phosphoric acid supported silica on ceramics are recently being tested. In this study, we investigated the nm pore rice husk silica as a support for phosphoric acid and tested the electric conductivity of the silica plate and the characteristics of a prototype fuel cell H2|Pt|H3PO4/RHS|Pt|O2 at 100–200 °C. The conductivity of H3PO4/RHS was 8 mS cm −1 above 175 °C under 200 torr H2O. In the fuel cell, the apparent conductance of the electrolyte from I−V characteristics was 2.45 mS/cm at 160 °C under 1 atm H2 and air at present.

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Porous YSZ(8 mol% yttria-stabilized zirconia) was prepared by an acid leaching of ZnO-YSZ composite. The ZnO-YSZ composites were obtained by two different methods, a 1450 °C sintering of the mechanical mixture of ZnO and YSZ powders or a decomposition of Zn(NO3)2 deposited on YSZ and a subsequent sintering. The XRD (X-ray diffraction) pattern of the composite indicated that it was a mixture of ZnO and YSZ even after the sintering. Sharp edge or round edge of YSZ was observed in SEM (Scanning Electron Microscope) image of the porous-YSZ from the mixture of ZnO and YSZ, or Zn(NO3)2 deposited on YSZ, respectively. The porous YSZ from the composite having ZnO component greater than 60 wt% shows low mechanical strength. As the ZnO content of the composite increased, the porosity and gas permeability of the porous YSZ increased. From the result, it was suggested that ZnO is a candidate to generate pores in YSZ bulk or membrane.