Engineering Research Seminar Series 31, 2011: Characterisation of Nanostructured ZnO Thin Films as Photocatalyst

Dr Arshid Mahmood Ali, a graduate from University of Auckland, New Zealand

Date: 2011-08-18
Time: 11:00 to 12:00
Venue: Classroom 6-3-01


The objective of this talk is to evaluate the suitability of nanostructured ZnO thin films as efficient photocatalysts and to characterise any issues that may be involved in the scale-up of photocatalytic systems based on these types of immobilised nanostructure ZnO thin films. In particular, this study involved fabricating and then evaluating the effectiveness of a range of nanostructured  zinc oxide (ZnO) thin films with different structures and chemistries as photocatalysts, and thereafter to systematically relate: the initial and reacted surface morphology; photocatalytic activity in terms of reaction rate; reaction intermediates and products; and liquid phase and solid phase reaction mechanisms under both limited and rich oxygen conditions at two different UV irradiation wavelengths (254nm and 340nm). These nanostructured thin films were produced using an innovative combination of magnetron sputtered surfaces and hydrothermal solution deposition that allows the morphology, porosity and thickness to be controlled by varying the composition and processing conditions. Results showed a clear relationship between surface morphology (and the related thin film preparation method) and photocatalytic activity for the ZnO thin film supported catalysts: the tallest, most aligned structure had the highest photocatalytic activity, whilst the smallest, least aligned structure had the lowest. Adding oxygen made the films more stable: in oxygen-limited conditions, SEM and atomic absorption spectroscopy indicated zinc leaching had occurred.


About the Speaker

Arshid Mahmood Ali has recently received his PhD in Chemical & Materials Engineering from University of Auckland, New Zealand. He was a lecturer in Institute of Chemical Engineering & Technology (ICET), Pakistan from 2005 to 2007 and a Research Fellow from 2003 to 2005 with the same institution. Prior to that, he was attached to ICL International, Pakistan as a Process Manager from 2001-2003.