Based On The Intermolecular Weak Interaction Adjustment Of Hydrothermal Synthesis Of Nanomaterials

Nano-materials prepared based on the modulate of weak reciprocity between molecules always have different morphologies because of different reaction temperature, time, solvent and complexing agent. Meanwhile, the reciprocity between molecules could be adjusted by the change of factors of kind of complexing agent and reaction time et al. This would affect the process of nucleation and growth of crystal, which is benefit for control of product. And then achieve the gole of performance optimization. The materials made in this way would show superior function. In this thesis, Cerium nitrate and oxalic acid are selected and a simple precipitator method is used to prepare ceria octahedrons pass through hydrothermal process. A self-sacrifice template mechanism is proposed for the formation of ceria octahedrons based on the experimental. It was found that reaction temperature and time would have an impact on morphologies and crystal process. Crystal growth in lower temperature has a similar growth process with high temperature, but reaction time is much longer. Hematite microcapsules with and without etching are fabricated controllably through adjusting the synthesis temperature via a3,3-thiodipropionic acid (TPA)-assisted hydrothermal synthesis method. Hematite nanorods can be obtained after the calcination of akaganeite nanorods which were prepared at a low synthesis temperature. Based on the experimental results, it is suggested that at the early stage the synthesis of akaganeite and hematite samples involves the hydrolysis of ferric chloride to promote nucle-ation in the presence of TPA and subsequently experiences the coordination-assisted growth guided by the ligand of TPA. Magnetic hysteresis measurements show that the size and shape of the hematite micro-/nanostructures have important effects on their magnetic properties. Furthermore, hematite nanorods display the best electrochemical sensing behavior toward the reduction of H2O2among these hematite samples. Two kinds of Pd nanoparticle aggregates with different electrocatalytic activity are developed in a facile hydrothermal synthesis method. The average size of Pd anoparticles synthesized from the mixed solvent containing water and acetone (Pd-M) is-9nm smaller than that of Pd samples synthesized from aqueous systems (Pd-A) with the size of-14nm. Nanoparticles of Pd-M and Pd-A show the crystalline nature based on the XRD and HRTEM results. It is found that Pd-M display a remarkably high electrooxidation activity per unit mass toward formic acid and ethanol, which is8-12times as high as that of Pd-A. The electrooxidation activity per unit area of Pd-M is also higher than that of Pd-A. The formation mechanisms of Pd-A and Pd-M as well as the relationship between their microstructures and electrocatalytic activity have been discussed based on the experimental results.