Preparation And Characterization Of Nano-SnO₂ With Template Method Of Nanocrystalline Cellulose

Nano tin dioxide is a n-type wide band gap semiconductor material.It has excellent gas-sensitive properties and photoelectric properties.As a new functional material,it has been applied to gas sensors and humidity sensors,electrode materials,optical glass,catalysts,functional ceramics,etc.There are a lot of methods to prepare inorganic nano-materials,including biological template method,which is a green,efficient and convenient way to realize the preparation of special materials through using the natural biological structure and thus has been highly concerned.Cellulose is one of the most abundant renewable organic on the earth.It is a polyhydric macromolecular substance,which can form supermolecule through hydrogen bonding between molecules and can be used as a template to guide the growth of nanocrystals.Using cellulose to prepare nano-materials has many advantages for its rich resources,renewable and low cost characteristics,etc.SnO₂-CNC samples were prepared at room temperature through SnCl₄·5H2O as the precursor of tin source,nanocrystalline cellulose?CNC?as the template and ethanol-water as the mixed solvent.Then nano SnO₂ samples were obtained after calcinations.The nano SnO₂ samples and SnO₂-CNC samples were characterized by FT-IR,TEM,XRD and TG.Then the effects of SnCl₄ addition,SnCl₄ concentration,reaction time and calcination temperature on the particle sizes of nano SnO₂ were explored.The light degradation properties of SnO₂-CNC and SnO₂ samples on methyl orange under weak UV-irradiation were characterized by UV.It is concluded that after five hours of weak UV-irradiation,the degradation rates of SnO₂-CNC samples on methyl orange are better than those of SnO₂ samples,and the SnO₂-CNC samples have a better photocatalytic property.The SnO₂-CNC samples were modified by nitrogen doping and the SnO₂-CNC-N samples were characterized by XRD and TG and compared with the results of SnO₂-CNCsamples,then the changing trend was analyzed.The light degradation experiments on methyl orange showed that when the light degradation is up to 5 hours,the light degradation properties of nitrogen-doped samples are not all higher than those of the original products,SnO₂.Then the light degradation change trends of different samples and its causes were analyzed.The light degradation of methyl orange was compared between SnO₂-CNC-N samples and the previous prepared SnO₂-CNC samples.It is found that the light degradation effects of methyl orange for the nitrogen-doped CNC-SnO₂-N samples under weak UV-irradiation are all higher than those of non nitrogen-doped SnO₂-CNC samples,and its causes were analyzed.Two preparation methods were used for the SnO₂-CNC samples doped with silver,and their reaction mechanisms were investigated.The SnO₂-CNC-Ag samples were characterized by TEM.The SnO₂-CNC-Ag samples prepared by two methods were characterized by weak ultraviolet light degradation of methyl orange.The light degradation performance of the samples increased first and then decreased with the increasing concentration of silver particles.The silver doped SnO₂-CNC samples were compared with the SnO₂-CNC sample through light degradation of methyl orange.The silver doped SnO₂-CNC sample exhibited better light degradation performance than the undoped SnO₂-CNC sample.The silver doped SnO₂-CNC samples were compared with the nitrogen-doped SnO₂-CNC sample through light degradation of methyl orange.The silver doped SnO₂-CNC sample showed better light degradation performance than the nitrogen-doped SnO₂-CNC sample.