In this study, zinc oxide (ZnO) nanorod arrays were synthesized using a simple hydrothermal reaction on a ZnO seeds/
ITO substrate and applied for the fabrication of enzymatic glucose sensor. ZnO nanorod matrix provided a favourable
environment for the immobilization of glucose oxidase (GOx) and introduced a shuttling way for electronic communication
between GOx and electrode. The performance of different aspect ratio of ZnO nanorods that was produced by varying
hydrothermal reaction time was studied. The aspect ratio of ZnO influenced the GOx enzyme immobilization. The
morphology and structure of prepared ZnO nanorods were characterized by employing scanning electron microscopy
(SEM), and X-ray powder diffraction (XRD). Electrochemical measurements of the sensor showed a reproducible sensitivity
of 2.06 μA/cm2
mM for ZnO matrix grown for 4 h with the aspect ratio of 8.0.
In the formation of ZrO2 (zirconia) nanotubes (ZNTs) by anodisation of zirconium, a balance between chemical etching at the surface of the nanotubes and inward growth inside the nanotubes is required. This can be achieved by using fluorinated organic electrolyte like ethylene glycol with the addition of small volume of oxidant. In this work, carbonate was selected as the oxidant and NH4F as the source of fluoride for chemical etching process. Two sets of electrolytes were studied EG/fluoride/Na2CO3 and EG/fluoride/K2CO3. It appears that in the presence of carbonate evolution of gas at the anode during the anodisation process was rather severe. The gas which is likely to be CO2 was found to weaken the adherence between the oxide film with the underlying Zr foil. This induced the formation of free standing ZNTs. High Resolution Transmission Electron Microscope (HRTEM) was used to investigate the crystallinity of the nanotubes where the majority crystal phase of ZNTs was tetragonal/cubic. The ZNTs were used as photocatalysts to oxidize methyl orange dye.