Design,Snthesis And Photocatalytic Properties Of ?-? Semiconductor Micro-nanostructures

?-? semiconductor has special photoelectric properties,which has been applied in many fields.Especially,ZnO and ZnSe have been the research focuses of semiconductor photocatalysis.Because the structure of semiconductor has great influence on its optoelectronic properties,the design and control the structure of semiconductor is meaningful.On the one hand,the semiconductor?ZnO or ZnSe?with various morphology has different photocatalysis properties;on the other hand,the Type-II heterojunction of ZnO/ZnSe can exhibit dramatically photocatalysis properties campared to bare ZnO and ZnSe.Here,three kinds of morphology of ZnO?rod-,block-and flower-like?were synthesized via simple hydrathermal approach.First,the morphology of ZnO was adjusted through choosing different substrate during the process of hydrathermal.The results showed that the ZnO rods were obtained whitout the substrate;while the product was the mixtrure of block-like ZnO and Zn?OH?₂;and the flower-like ZnO was achieved when the graphite was chosen as substrate.The influence mechanism of substrates on the morphology of ZnO was also investigated.Morevoer,the three-dimensional flower-like ZnO showed the best photocatalysis properties,compared with the other two samples.Second,by means of changing the amount of ethylenediamine,two types of ZnO morphology?microsphere,microsheet?were fabricated through simple sloventthermal method.To decrease the aggregation of ZnSe in the growth process,the hydrazine was chosen as reducing agent and complexing agent to synthesize ZnSe microsphere and microsheet with high monodispersion.Meanwhile,the role of ethylenediamine and hydrazine on the growth of ZnO has been studied;Morevoer,the compared photocatalytic activity of ZnSe was investigated by photocatalytic degradation of methyl orange solution,the restult showed that the ZnSe microsheet with larger specific surface area has higher photocatalytic property.Third,two heterojunction structures of ZnO/ZnSe were desinged based on the above samples,in which the ZnO rods were used as Zn source,and ZnO rod/ZnSe sphere and ZnO rod/ZnSe sheet were obtained by changing the concentration of ammonia water.What's more,the effect of sodium borohydride on the morphology of the heterojunction was also investigated.The photocatalytic activity of methyl orange solution showed that the photocatalytic activity of heterojunction composite is much higher than that of bare ZnO or ZnSe.Especially,the ZnO rod/ZnSe microsheet exhibited the highest photocatalytic activity.