Preparation And Properties Of Cu-M (M=Fe,Co,Ni) And Sn-M (M=Cu,Co) Nanomaterials

Compared with the bulk metal,nanomaterials possess high mechanical strength,good malleability,and electric-magnetic properties because of their small-size effect,surface effect,and quantum-size effect.Bimetallic nanomaterials exhibit particular physical and chemical characteristics and have potential applications in the fields of catalysis,magnetic recording,sensing,and medical diagnosis,etc.Due to the high catalytic activity and high chemical stability,noble metal materials have been attracting great interests of the scholar.However,the cost of noble metal materials is exceedingly expensive on account of the limited resource on the earth.The supported metal nanomaterials can decrease the usage of noble metal,but we have to overcome the limited stability of them and their tendency to leach out?especially under extreme conditions such as high temperature/pressure?.Apart from these,the recycling of catalysts is also a challenge to be addressed.It is of great significance to develop catalysts with great stability,catalytic activity,and recyclability.Considering these,we combine the copper that is rich in reserves and has high activity in some catalytic reactions with magnetic metals such as iron,cobalt,and nickel.In this paper,we mainly discuss the structure and catalysis of Cu-M bimetallic materials'ability to decompose Congo red.Besides,the thermal properties of bimetallic nanomaterials which consist of tin,copper,and cobalt-based on the research of our group are tested.The report runs as follows:?1?We synthesized dendritic Cu-Co,Cu-Ni bimetallic nanomaterials,and sheet-shaped Cu-Fe bimetallic nanomaterials under strongly alkaline conditions by ethylenediamine serving as a regulator and hydrazine hydrate serving as a reducing agent.The composition and morphology structure of materials we synthesized are tested by XRD,SEM,TEM,Mapping,and other characterization methods.We laid our point on the influence of metal atom and the molar ratio of reacted metal ions to the catalysts'structure and the growth mechanism.It was found that the Cu²⁺was reduced firstly and the Ni²⁺,Co²⁺,Fe³⁺were reduced subsequently in the co-reduction system due to the differences in reduction potentials.Under the regulation of ethylenediamine,products with different morphologies can be obtained.?2?The catalytic reduction of Congo red by Na BH₄ in the presence of Cu-M nanomaterials was conducted.The changes in absorbance of reacted solutions were recorded by the ultraviolet spectrophotometer.We tested the degradation rate of Congo red by changing the concentration of sodium borohydride and the Cu-M materials.The p H value of the buffer solution to the influence of reduction was also conducted.We concluded that the more alkaline of the solution was,the lower the degradation rate of Congo red we got.The degradation rate of Congo red increased within a certain range along with the increase of the concentration of catalyst or sodium borohydride.The catalytic activity of Cu_0.6Fe_0.4 was the best of the materials we made.Congo red could convert into other small molecules in four minutes in the presence of Cu_0.6Fe_0.4.?3?Stannous chloride,copper nitrate,and cobalt nitrate were served as the metal precursor of Sn-M bimetal nanomaterials.The varieties of reducing agent,surfactant,and reaction medium were changed during the preparation of Sn-M.In the meantime,the thermal properties of Sn-M were also investigated.It was found that the change of the thermal properties of Sn-based nanomaterials is relevant to the type and amount of doped metals.The doped Co can better reduce the supercooling of molten tin with stronger nucleation ability.The crystallization temperature of Sn-Co@SiO₂ is significantly higher than Sn-Cu@SiO₂ under the same doping amount.Doping Co into Sn can effectively decrease the supercooling of Sn-based nanomaterials.