title: Sol-gel growth of hexagonal faceted ZnO prism quantum dots with polar surfaces for enhanced photocatalytic activity.
abstract: The hexagonal faceted ZnO quantum dots (QDs) about 3-4 nm have been prepared via a sol-gel route by using oleic acid (OA) as the capping agent. It is revealed by electron diffraction patterns and high resolution transmission electron microscopy lattice images that the profile surfaces of the highly crystalline ZnO QDs are mainly composed of {100} planes, with the Zn-terminated (001) faces and the opposite (001) faces presented as polar planes. Compared with spherical ZnO QDs, the hexagonal faceted ZnO QDs show enhanced photocatalytic activity for photocatalytic decomposition of methylene blue. A mechanism for the enhanced photocatalytic activity of the hexagonal faceted ZnO QDs for degradation of methylene blue is proposed. In addition to the large specific surface areas due to small size and high crystalline, the enhanced photocatalytic activity can mainly be ascribed to the special hexagonal morphology. The Zn-terminated (001) and O-terminated (001) polar faces are facile to adsorb oxygen molecules and OH(-) ions, resulting in a greater production rate of H(2)O(2) and OH(*) radicals, hence promoting the photocatalysis reaction. The synthesized hexagonal-shaped ZnO QDs with high photocatalytic efficiency will find widespread potential applications in environmental and biological fields.
authors.affiliation: Key Laboratory for Liquid-Solid Structural Evolution & Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China.
authors.forename: Luyuan
authors.initials: L
authors.lastname: Zhang
authors.forename: Longwei
authors.initials: L
authors.lastname: Yin
authors.forename: Chengxiang
authors.initials: C
authors.lastname: Wang
authors.forename: Ning
authors.initials: N
authors.lastname: Lun
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Qi
mesh_terms: D000327:Adsorption; D002384:Catalysis; D046529:Microscopy, Electron, Transmission / Q000379:methods; D010100:Oxygen / Q000737:chemistry; D044367:Phase Transition; D010777:Photochemistry / Q000379:methods*; D045663:Quantum Dots; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013499:Surface Properties; D013997:Time Factors; D014961:X-Ray Diffraction; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D010100:Oxygen; D015034:Zinc Oxide