Novel hierarchical structure of ZnO: Growth of spiny tetrapod via vapor phase synthesis

Two types of tetrapod ZnO structures are synthesized in different temperature regions of the same apparatus by a simple vapor phase synthesis, in which a novel hierarchical ZnO structure — spiny tetrapod — is first reported. The results of XRD, SEM, and BET analysis show that the products are highly crystalline ZnO, while the spiny tetrapod is covered with numerous nanosized spine crystals and significantly large surface area in comparison with the conventional smooth tetrapod. The growth process of the spiny tetrapod is proposed by a two-step mechanism, namely, the formation of a smooth tetrapod at first and further growth of spine crystals on its surface. The results suggest that spiny tetrapod ZnO is a promising candidate for applications such as photocatalysts.