In recent years, semiconductor photocatalysis has become more
and more attractive and important since it has a great potential in
solving environmental problems. One of the most important
aspects of environmental photocatalysis is the selection of photoactive
materials. Semiconductor materials like ZnO and TiO2 are
two of the ideal photocatalysts in several respects. Both provide
photo-generated holes with high oxidizing power due to their wide
band gap energy and especially zinc oxide is relatively inexpensive