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

Abstract EN

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.