Particle size of powders under hydrothermal conditions

Abstract

Various non-oxide (CuI, AgI, AgCl, PbS, CuS and ZnS) and oxide (ZnO, TiO 2 , SnO 2 , CeO 2 and ZrO 2 ) powders were prepared under hydrothermal conditions to investigate the effects of temperature, pH and precursors on the particle size of powders. It was found that the particle sizes of PbS, CuS and ZnS powders were much smaller than that of CuI, AgI and AgCl powders prepared under the same conditions. The particle sizes of TiO 2 , SnO 2 , CeO 2 and ZrO 2 powders are much smaller than that of ZnO powders prepared under the same conditions. It is concluded that the solution conditions have a certain effect on the particle size of powders under the hydrothermal conditions. The particle size of powders increased with the rising of temperature. Additional factors affecting the particle size were uncovered through studying the nucleation mechanism. The particle size was mainly related to the Madelung constant and the electric charge number of ions. Powders with smaller particle size resulted from systems that possessed the larger Madelung constant and ionic charge number.

Study on effects of time and temperature on growth of nanocrystalline zinc selenide synthesized by hydrothermal method

“…After Se 2 À reaches the surface of a zinc particle, it combines with zinc via charge transfer [6], i.e., ZnSe begins to nucleate on the surface of the zinc particle. After the formation of a ZnSe nucleus, it is grown by diffusion of [Zn(OH) 4 ] 2 À and Se 2 À [14], but the little amount of [Zn(OH) 4 ] 2 À and H 2 restricts its size. Thus, the size of the formed ZnSe particles is small.…”

Preparation of α-Fe2O3 submicro-flowers by a hydrothermal approach and their electrochemical performance in lithium-ion batteries

“…Various crystalline powders with high purity, phase homogeneity, controlled morphology, narrow particle size distribution, little or no macroscopic agglomeration, and excellent reproducibility can be produced by this technique, due to a combination of simple equipment with easy sintering and less time consumption than in other methods [9,10].…”

Effect of pH on ZnO nanoparticle properties synthesized by sol–gel centrifugation

“…The pH affects the hydrolysis and condensation behavior of the solution during gel formation and therefore influences the morphology of the ZnO [11]. For instance, Li et al [12] showed that the solution conditions have a particular effect on ZnO particle-size powders. The pH can also change the number of ZnO nuclei and growth units [13].…”