Study On Preparation And Applications Of Nanosilver Composites

Metal nanomaterials have been widely used in environmental sciences,photoelectric sensing,biomedicine and other fields due to their excellent surface properties,chemical activity,optical properties and electrical conductivity.As an emerging functional material in metal nanomaterials,nanosilver has aroused wide concern in the filed of catalysis,sensing,antibacterial and other applications attributed to its unique physical and chemical properties.The advantages in performance and structure would be given full play by multiple components in silver nanocomposites.And rational structure could be designed to achieve better performance than a single component.Herein,the preparation of photocatalysts compounded heterojunction semiconductor with silver nanoparticles was studied,and the mechanism of enhancing photocatalytic properties by using silver nanoparticles as cocatalysts was discussed in depth.Silver nanowires with uniform size and high aspect ratio were prepared,which was combined with organic piezoelectric polymer.By adjusting the content of silver nanowires,the composite piezoelectric devices with enhanced properties were obtained.The main findings are as follows:(1)Bi₂O₃-TiO₂ heterojunction photocatalysts were synthesized by combining sacrificial template and impregnation calcination methods.Using photoreduction method,Ag NPs@Bi₂O₃-TiO₂ composite photocatalysts were obtained by loading small-sized silver nanoparticles on the heterojunction photocatalysts.The effect on the photocatalytic performance of composite photocatalysts with silver nanoparticles as cocatalysts was researched.The results showed that the removal rate of rhodamine B by using composite photocatalysts reached 100%within 90 min.Within 120 min,the removal rate of tetracycline hydrochloride reached 92%.Also,Ag NPs@Bi₂O₃-TiO₂ composite photocatalysts showed good cycling stability for the degradation of organic pollutants.(2)Silver nanowires were synthesized by polyol method using Cl^-,Br^-and Fe³⁺as control agents.The effects of Br^-and Fe³⁺ concentration,the methods for mixing precursor solution and temperature control on the morphology and size of silver nanowires were studied in depth.The silver nanowires with an aspect ratio of 1125(average diameter about 80 nm,length about 90 ?m)were obtained.The silver nanowires/polyvinylidene fluoride fiber composite piezoelectric sensors can be obtained by adding silver nanowires to the polyvinylidene fluoride fiber matrix.The piezoelectric response performance of composite piezoelectric sensors with different content of silver nanowires were tested.The output voltage and output current of the composite piezoelectric sensors with the optimal content of silver nanowires can reach 124 V and 0.13 ?A,respectively.And the composite piezoelectric sensors can be used in LCD driving,wearable testing and other scenarios.