ZnO with Different Morphologies Synthesized by Solvothermal Methods for Enhanced Photocatalytic Activity

Abstract

ZnO materials with a range of different morphologies have been synthesized via a simple solvothermal method with different solvents. Zinc acetylacetonate was used as the zinc source in such solvothermal syntheses for the first time. XRD data showed that single-phase ZnO with the wurtzite crystal structure was obtained for all the solvents used. FE-SEM imaging showed that ZnO with cauliflower-like, truncated hexagonal conical, tubular and rodlike, hourglass-like, nanorods, and spherical shapes were produced when THF, decane, water, toluene, ethanol, and acetone were used as the solvent, respectively. The TEM data showed that the crystalline ZnO had different growth habits in the different solvents. The optical properties of the as-prepared ZnO materials were investigated by UV-vis absorption and room temperature photoluminescence. Photodegradation of phenol was used as a model reaction to test the photocatalytic activity of the ZnO samples. ZnO samples with different morphologies and crystal growth habits exhibited different activities to phenol degradation. The ZnO material prepared using THF as the solvent showed a nine-times enhancement of the kinetic rate constants over commercial ZnO (0.1496 min -1 vs 0.0182 min -1 ). The influence of the solvents on the morphology of ZnO samples and the effect of the morphologies on the photocatalytic activity are discussed.

Morphology engineering of ZnO nanostructures

“…Even within the temperature range, the texture along the c-axis is improved and more cores are oriented with their c-plane parallel to the substrate. This is confirmed by the XRD spectrum of the ZnO "cabbages": the peak, related to the (0001) plane is more intense, although the other two peaks are present, related to the respectively (10-10) and (10)(11) planes. The characteristic size of the "cabbages" is around 1.5 -2 μm.…”

“…Zinc acetylacetonate (ZnAcAc) 2 is a convenient zinc oxide precursor for the vapor transport method, such as CVD [11,12] and is an alternative for the mainly used zinc precursors diethylzinc (DEZ-Zn(C 2 H 5 ) 2 ) or dimethylzinc (DMZ -Zn(CH 3 ) 2 ). As a solid state precursor, it has low sublimation temperature and high vapor pressure [13].…”

Preparation of Flower-like ZnO Nanoparticles in a Cellulose Hydrogel Microreactor

“…As reported previously, photocatalysts with higher surface energies exhibit better photocatalytic performances. Moreover, the (0001) plane exhibits the highest surface energy for ZnO Xu et al 2009). Thus, the flower-like ZnO nanosheets, which had large areas in the (0001) orientation, exhibited good photocatalytic activities.…”

Surfactant-assisted chemical vapour deposition of high-performance small-diameter GaSb nanowires

“…In the present study, we explore the use of surfactant (sulfur) for the CVD growth of NWs in order to achieve very thin GaSb NWs with the diameter down to 20 nm. In contrast to the surfactant effect typically reported in the liquid phase [22][23][24][25][26][27] (for example, solvothermal and hydrothermal) and thin-film technologies 28 , the sulfur atoms, commonly used for the surface passivation of III-V semiconductors [29][30][31][32] , are contributed to form S-Sb bonds on the as-grown NW surface, effectively stabilizing the sidewalls and thus minimizing the unintentional radial growth. Importantly, the obtained NWs are highly stoichiometric, single-crystalline with a smooth surface and very uniform in diameter without any tapering.…”