The mechanism is controlled by the interaction of foreign oxygen molecule and semiconductor in the near surface area.
The activity of several TiO2/SiO2 photocatalysts for cyanide and methanol photooxidation have been analysed and compared with pure TiO2 materials in terms of equal mass of semiconductor, photonic efficiency and active surface area.
As gas adsorption occurs at surface level, an increase in the active surface area of the semiconductor oxide would enhance the properties of materials used as gas sensors [4, 13 15].
Semiconductor nanowires have high aspect ratio, high surface area, and single crystallinity and thus are ideal building blocks for many devices on a nanometer scale [1, 2].
Generally, the performances of semiconductor oxide photocatalysts are dependent on the surface area, mesoporosity, crystallinity, morphology [31], and active facets exposed [32].
Because of their high specific surface area values, nanostructured oxide semiconductors can be applied with high efficiency in various photoexcited devices [1 3].
Since, the efficiency of the DSSC relies on the sensitizer and semiconductor, the idea here is to increase the absorption band of the sensitizer by increasing its surface area or decrease the electron hole recombination rate using darker co-semiconductor to achieve higher solar conversion efficiency.
A semiconductor photocatalyst with high activity should have high crystalline and large specific surface area.
Due to their increased cross-section and surface area as well as the size-dependent quantum confinement, semiconductor nanowires (NWs) have been successfully utilized in numerous device applications such as solar cells, LEDs, and FETs [1 8].
Its ability to be grown in a wide variety of nanostructured morphologies, allowing the designing of the surface area architecture constitutes an important advantage over other semiconductors.
Nanostructured semiconductors offer potential advantages in PEC application due to their large surface area and size-dependent properties, such as increased absorption coefficient, increased band-gap energy and reduced carrier-scattering rate.
