Hydrothermally controlled ZnO nanosheet self-assembled hollow spheres/hierarchical aggregates and their photocatalytic activities

Abstract

We synthesized ZnO nano-micro structures, including microrods, nanosheets, a nanosheet selfassembled hollow sphere (NSHS), and a hollow hierarchical aggregate (HHA) by changing the concentration of trisodium citrate in a hydrothermal process. The NSHS was formed by the self-assembly of 2D nanosheets on the surface of a formaldehyde bubble, while the HHA was obtained by the self-assembly and hierarchical arrangement of NSHS. The photocatalytic activities of the ZnO structures were evaluated from the degradation of methylene blue under visible and black light irradiation. The NSHS showed better photocatalytic performance due to its excellent photon absorbance, low defect density and low emission quantum yield compared with the HHA. Furthermore, the size and number of the 2D nanosheets hydrothermally grown on the NSHS bubble template were controlled by changing the growth temperature.

Fabrication of Au/GO/ZnO composite nanostructures with excellent photocatalytic performance

“…In the hydrothermal process, zinc nitrate acts as a Zn 2þ precursor and hexamethylenetetramine reacts with water to produce hydroxide anion (OH À ) under reflux at 95 C. Zn 2þ reacts with OH À to produce ZnO nanostructure [25]. The reactions involved in the synthesis of ZnO as follows:…”

Piezotronic-effect-enhanced Ag2S/ZnO photocatalyst for organic dye degradation

“…[26][27][28][29][30][31][32][33][34][35] Many previous studies have been conducted to enhance the photocatalytic activity of ZnO using different morphologies, including nanoparticles, nanotubes, and hollow spheres. [36][37][38][39] The basic strategies for improving the photocatalytic activity of ZnO are extending the light response range and inhibiting the photoexcited charge carrier recombination. Although metal suldes (M x S) have been extensively used as photocatalysts, until recently they have not been employed in photocatalytic composites.…”

An investigation of optical properties of zinc oxide nanoparticle synthesized by starch mediated assembly and its application in photocatalytic bleaching of methyl green and rhodamine-B

“…These ZnONP interacted with hydroxyl groups of amylopectin and trapped in the branched structure of amylopectin [17]. Khoa et al also reported the hollow spheres of ZnOassembled (wrapped with Au/grapheme) and self- assembled ZnO nanosheet with photocatalytic potential [18,19].…”