In this work, two-dimensional (2D) Zn-HMT (Zn(NO3)2(HMT)2(H2O)2]n) nanosheets were synthesized using a facile one-step chemical precipitation in the presence of Zn(NO3)2, hexamine (HMT), and anhydrous ethanol at room temperature. Subsequently, hexagonal Tx-ZnO (Tx-ZnO refers to the zinc oxide (ZnO) nanoparticles) were synthesized by a high-temperature solid-phase method at different temperatures (x = 500, 550, 600, 650, 700, 750, and 800 °C) nanoparticles with different morphologies were synthesized by a high-temperature calcination approach using 2D Zn-HMT nanosheets as precursor. The crystal structure, morphology, specific surface areas, surface and interface properties, optical properties, and charge migration behaviors of the as-synthesized Tx-ZnO nanoparticles were characterized by powder X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), automatic specific surface and aperture analyzer, X-ray photoelectron spectroscopy (XPS), UV-visible spectrophotometer, photoluminescence (PL) spectra, and electrochemical impedance spectroscopy (EIS). The photocatalytic performances and stabilities of the as-synthesized typical Tx-ZnO nanoparticles with various morphologies were evaluated and compared with the commercial ZnO (CM-ZnO) nanoparticle. The T700-ZnO nanoparticle with spherical and irregular morphology exhibited the highest photocatalytic activity (99.12%) for the degradation of Rhodamine B (RhB), compared to T500-ZnO (92.32%), T600-ZnO (90.65%), T800-ZnO (44.04%), and the CM-ZnO (88.38%) nanoparticle, which can be attributed to the cooperative effects of higher crystallinity, bigger crystal size, the strongest separation efficiency, the lowest recombination rate, the fastest charge carrier transfer path, and the highest charge-transfer efficiency. The superior photocatalytic activity illustrated by the T700-ZnO nanoparticle makes it have potential application prospects for the treatment of organic wastewater.

In this paper, the chemical reduction method was used to prepare silver nanoparticles with different morphologies and sizes by controlling the proportion of ascorbic acid and silver nitrate at room temperature. In the experiment, the molar ratio of ascorbic acid and silver nitrate was mainly 1:1, 1:2, 1:4, 1:8, 2:1, 4:1 and 8:1 to prepare nano silver. The morphology of silver nanoparticles was observed by scanning electron microscopy (SEM) and the phase content was determined by X-ray diffraction (XRD). The results show that the obtained material is pure silver nanoparticles, and the silver nanoparticles are spherical and multilevel branched.

Au nanorods were prepared by seed growth method. Based on the local surface plasmon resonance (SPR) absorption spectra of gold nanoparticles, the formation and growth kinetics of gold nanorods were observed and studied in real time. The effects of temperature and reaction time on the growth process of gold nanorods were emphatically investigated. It was found that the shift of SPR UV-vis absorption peak was closely related to the experimental conditions The influence factors and mechanism of SPR absorption peak shift are discussed. It is concluded that the moving direction of SPR peak is the result of the competition of particle size and charge transfer.