In-situ Preparation Of Porous Silver On Copper Materials And Its Multifunctional Application

Based on the unique and excellent physical and chemical properties of noble metal nanomaterials,the preparation and application of noble metal nanomaterials have been deeply explored.Various nanostructures with different morphologies for different applications have been developed.Among the existing noble metal nanostructures,the porous structure not only retains the excellent physical and chemical properties of the noble metal,but also has the characteristics of large specific surface area,high porosity,abundant active sites,and high mass transfer rate,so it has received extensive attention.As a typical noble metal,silver has relatively low price compared to other types of noble metals.Porous silver has a wide range of application prospects in the fields of catalysis,sensing,surface-enhanced Raman spectroscopy(SERS),and medicine.In recent years,people have made a series of breakthroughs and progress in the morphology control,composition optimization and synthesis mechanism of porous silver nanostructures.At present,synthesis methods such as alloying method,template method and physical deposition have been successfully developed.However,these methods often require complex operation steps and equipment,so there are certain obstacles in the industrial expansion of production and promotion.Therefore,finding a more reasonable and effective method to synthesize porous silver with typical morphology and excellent performance has been a hot theme in this field.In this paper,the controllable preparation of porous silver materials is the focus.A facile and efficient strategy for the in-situ synthesis of porous silver on copper materials based on the galvanic replacement reaction was developed and the multifunctional application potential of porous silver in different fields was explored.The specific research contents are as follows:(1)Porous silver in situ supported on copper materials was prepared based on the galvanic replacement reaction between copper and silver nitrate.2-chlorobenzoic acid and chloride ion(Cl-)were used as the regulating molecule and etchant for the reaction,respectively.In order to obtain the ideal porous silver structure,the reaction conditions involved in the synthesis process were optimized.As a result,the prepared porous silver structure in the form of curving nanosheets could be synthesized in just 5 minutes.The formation mechanism of porous silver was also further explored,and the results proved that the presence of Cl-had an important influence on the formation of the porous structure.Compared with other synthesis methods,this method has the following advantages.First,the process is only limited by the potential difference between the two metals,which is easy to implement and easy to achieve scaled production;second,in the galvanic replacement reaction,the oxidized metal can be used as the substrate to support the newly generated silver nanostructure in situ,which can effectively avoid the structural damage and performance loss caused by the complex transfer process;the third is that the copper substrate type can be replaced according to different application requirements,so as to achieve multifunctional applications.We have successfully synthesized porous silver on copper foil and copper foam respectively.(2)The multifunctional application potential of the on-demand-fabricated porous silver supported on copper materials in catalysis and SERS was explored.The reduction process of 4Nitrophenol was used as a model reaction to investigate the static and fluidized catalytic ability of porous silver on copper foil and copper foam.The experimental results showed that the two different types of copper substrates had excellent catalytic performance,and had good recyclability and stability.The catalytic reduction efficiency can reach 96%.In addition,we explored the possibility of using porous silver supported on copper foil as a SERS substrate.The experiments proved that it had excellent sensitivity,good uniformity and high reusability and stability.The signal of thiram with the concentration as low as 10-6 M can also be detected successfully.The results demonstrate that the porous silver synthesized by this method has broad application prospects.