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Journal of Nanomaterials
Volume 2014 (2014), Article ID 426457, 6 pages
http://dx.doi.org/10.1155/2014/426457
Research Article

Investigation of the Photocatalytic Activity of ZnO Nanowires: Substrate Effect and Kinetics Analysis

Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan

Received 24 January 2014; Accepted 1 June 2014; Published 1 July 2014

Academic Editor: Yanbao Zhao

Copyright © 2014 Jan-Hau Chang and Heh-Nan Lin. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The photocatalytic activity of substrate-supported ZnO nanowires is investigated with a focus on the substrate effect and the photodegradation kinetics. The employed NWs are grown on various substrates by thermal evaporation and a 50 μM rhodamine B solution is used as the target solution. It is found that the photocatalytic activity is facilitated by using a conductive substrate and such a result can be reasonably attributed to the improvement of charge separation. The photodegradation is found to follow a zeroth-order kinetics at high concentrations and a first-order kinetics at low concentrations with a transition at around 10 μM. The present observation is opposed to the commonly accepted first-order kinetics. Degradation constants of 0.58 μM·min−1 for the zeroth-order and 0.028 min−1 for the first-order have been achieved. The first-order constant also compares favorably with reported values.