Lizhao Qin

Controllable green synthesis of Cu2O nanocrystals with shape evolution from octahedra to truncated octahedra

A simple controlled synthesis of Cu2O nanocrystals from octahedra to their different truncated forms was successfully achieved by using an ultrasonic method. The crystals were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), field emission scanning electron microscopy (FESEM), UV-vis spectroscopy (UV-vis) and transmission electron microscopy (TEM) as well as high-resolution transmission electron microscopy (HRTEM). The growth processes of cuprous oxide nanocrystals were analyzed and possible growth mechanisms were discussed. The optical properties of the obtained crystals were investigated.

Synthesis, stability, and intrinsic photocatalytic properties of vanadium diselenide

As a typical, layered, so-called semimetal, vanadium diselenide (VSe2) is significantly different from other transition metal dichalcogenides (TMDs). With an overlap in its energy band between conduction band (CB) and valence band (VB), it can hardly have the potential for optoelectronic applications in theory. However, excellent intrinsic photocatalytic properties have been found in bulk 1T-VSe2 for the first time in this study. Typically, 28 mg L−1 of methyl orange (MO) was completely degraded within 30 min by 3 mmol L−1 of bulk VSe2. Based on the experimental results, a new photocatalytic mechanism different from that for semiconductors has been proposed. Moreover, the stability of VSe2 was studied and the results indicated that VSe2 can decompose by itself under extreme conditions. Fortunately, its self-decomposition can be prevented in the photocatalytic process, which is meaningful for practical applications.

Photodeposition synthesis of a ZnO nanoporous layer

An original photodeposition methodology is investigated to synthesize novel ZnO nanoporous layers with high uniformity and pore density via TiO2 nanotube substrates (annealed at 450 °C under 10−2 Pa for 8 hours) immersed in Zn(NO3)2 aqueous solution (1 mol L−1) and irradiated by ultraviolet (UV) light at room temperature for 12 hours. Characterization of the material highlights that the nanoporous layer is assembled by the dominant (101) crystal plane of hexagonal wurtzite ZnO with a vertical sheet thickness of about 20 nm and an aperture diameter of around 100 nm. Vacuum annealing of the TiO2 substrate ultimately impacts the uniformity of the ZnO nanoporous layer, which can be essentially attributed to the density of the substrate oxygen vacancies. However, the concentration of the Zn(NO3)2 aqueous solution significantly influences the morphology and pore density of the porous layer. Furthermore, the ZnO nanoporous layer enhances the photoelectric properties of pure TiO2 nanotubes, which may provide general application prospects in photocatalysis and photoelectric devices.