Controlling Morphologies and Tuning the Related Properties of Nano/Microstructured ZnO Crystallites

Abstract

In this paper, we successfully synthesized three kinds of typical ZnO micro/nanocrystallites including flakes, columns, and pyramids by means of different facile wet chemical routes. The growth environment plays a crucial role in the morphologies of these ZnO micro/nanocrystallites. At the same time, we find that physical/chemical properties of these ZnO samples are dependent on their exposed surface, and the order of gas sensing and photocatalytic efficiency of the ZnO crystal planes is (0001) > {10 (1) over bar0} > {10 (1) over bar1} and (000 (1) over bar). On the basis of structural analyses of various exposed surfaces and related X-ray photoelectron spectroscopy, we deeply discussed the effect of definite surface structures on their gas sensing and photocatalytic properties.National Natural Science Foundation of China [20725310, 20721001, 20673085, 20801045]; National Basic Research Program of China [2007CB815303, 2009CB939804

OBTAINING ZnO IMMOBILIZED OVER DIFFERENT SUBSTRATES BY HYDROTHERMAL TREATMENT FOR PHOTOCATALYSIS APPLICATION

“…Furthermore, high crystal quality is made available because the material experiences no thermal stress during growth. Associating the XRD results with the photocatalytic degradation of RhB, it is possible to conclude that the growth increase along the c-axis does not provide better photocatalytic activity, contrary to what some authors claim, 2,8,14,19,20 no correlation between these parameters was observed. In analyzing the morphology of the samples and the photocatalytic activity response, it is apparent that a perfect formation of the microstructures composed by nanorods does not necessarily have the highest photocatalytic activity.…”

Room temperature sintering of polar ZnO nanosheets: I-evidence

“…Freshly calcined samples , with a separation distance between the parallel planes of ~0.24 nm, which is the plane that forms the surfaces of hexagonal pyramids sometimes found at the top of ZnO nanorods [15].…”

The interplay between morphology and photocatalytic activity in ZnO and N-doped ZnO crystals

“…Therefore, visible photocatalytic activity will be increased [15]. [8] Under visible illumination ( Figure 7B), the recombination rate also occurs, in less proportion than under UV illumination and the effect of SSA is considered. For MAH samples, the influence of doping process in the photocatalytic activity under UV illumination is negative.…”

“…Therefore, many efforts have been made to synthesize ZnO-based semiconductors with different morphologies for specific devices, such as nanorods, nanobelts, nanosheets, microrod/microtube arrays, quantum dots and other complex hierarchical micro/nanostructures [7,8]. Synthetic routes to ZnO nanoparticles include modified polymeric precursor (MPP) [9], sputtering [10,11], hydrothermal [12], solvothermal [13,14], sol-gel [15,16], ultrasonic irradiation [17], microwave-assisted hydrothermal (MAH) [6,18,19], and zinc-precursor thermal decomposition with free-solvent [20,21] methods.…”