Preparation And Morphology Of Cu₂O Micro/nanocrystals By Hydrothermal Reduction Method

Cu₂O is a rare type of P type semiconductor oxide material.It has potential applications in thin film transistors,photocatalytic decomposition of water,solar photoelectrochemistry,sensors,biosensors,printed electrons,lithium ion batteries,photocatalysts,cancer treatment agents,and antibacterial clean energy technology.Therefore,Cu₂O micronanoparticles have been widely studied in recent years.However,the properties of different morphologies of Cu₂O are different,and the controllable synthesis of Cu₂O with various morphologies is of great significance for its more efficient utilization.It is possible to control the appearance of micro and nano materials by changing the external environment of crystal growth.Generally speaking,the main ways to control the morphology of cuprous oxide are:?1?changing the pH value and concentration of solution,reaction temperature and time.?2?use different surfactants as soft templates and dispersants.?3?the use of different additives and reducing agents.In this paper,the above three ways are used to study the morphology of copper oxide micro/nano materials,and some research results have been obtained.The main contents and results of this paper are as follows:A hydrothermal synthesis method was used to synthesize concave eight-hedron,eight-hedral polyhedron,eight-hedron and rhomboid twelve-hedron with maltose,xylose and sucrose as reductants.The Cu₂O crystals,such as cube shape,two-dimensional branch shape and three dimensional branch shape,were synthesized.It is worth noting that the sucrose like non reducing sugar successfully synthesized the dendritic Cu₂O crystal.However,by comparing these kinds of carbohydrate reductants,it is found that the products produced by xylose are more diverse than maltose and sucrose,and the morphology is more complete.By adjusting the reaction conditions,it is found that different copper salts have a significant effect on the morphology of Cu₂O microcrystals.Using glycerol and xylitol as a reductant,the cube,the cube,and the Cu₂O crystal of the branch shape of the cube,the octagon and the inner heart are successfully synthesized.By controlling the proportion of glycerol to water,it is found that with the gradual reduction of the concentration of glycerol in the solvent,the morphological evolution of Cu₂O crystals with different solvent combinations has the following two tendencies:?1?the size and dispersion of the crystal are enhanced,and?2?etching of the{100}cubic oxide copper oxide crystal plane.The transformation of Cu₂O crystal morphology may be due to the crystallization kinetics of evolution and the solvent effect of oxidative corrosion.The decrease of glycerol concentration in the solvent weakened the reducibility of the system,but increased the solubility of the reactant,because H₂O is an excellent solvent for copper compounds.Therefore,reducing the supersaturation of the solution and the growth rate of Cu₂O monomer will directly lead to the formation of large monodisperse cuprous oxide crystals.The Cu₂O crystal synthesized with xylitol as a reductant is mainly eight-hedron and dendrite.With the increase of xylitol,the product Cu₂O evolved from eight-hedron to a branch-like crystal.With formic acid,L-glutamic acid,sorbic acid,EDTA,DMF as reducers,the eight-hedral,concave eight-hedral,eight-hedral,rod,three-dimensional,and flaky spherical Cu₂O crystals have been successfully prepared.The results show that the temperature has a certain influence on the shape of Cu₂O when L-glutamic acid is used as reducing agent.By adjusting the temperature,the crystal morphology can be transformed from rod like to eight-hedral to six-angle star.The effects of different copper salts on the size and dispersion of the products were also investigated.Sorbic acid is used as reducing agent to control the order of feeding,so that copper ions react with sodium hydroxide to form precursors and then add reductant to form Cu₂O spherulites.The reaction time was controlled by DMF as a reducing agent.With the increase of reaction time,the transformation from eight faces to the eight faces of the inner face and then to the six corner crystals was achieved.