Green Synthesis Of Noble Metal Based Porous Bimetallic Nanomaterials

As potential“green”solvents,ionic liquids?ILs?have many unique advantages which endow them some fascinating features to direct the formation of namomaterials with special morphology and outstanding properties.However,it is found that there are only several reports about the synthesis of bimetallic nanomaterials with the assistances of ILs.The newly-developed deep eutectic solvents?DESs?in recent years,with cheaper price,have many similar characteristics and properties as ILs and are considered as new classes of green solvents.However,there are a few reports on the preparation of inorganic nanomaterials,and no report is found in the preparation of bimetallic nanomaterials.Although noble metal Pt exhibits highly catalytic active as catalysts in fuel cells,the limited resource,expensive price,and catalyst poisoning hamper its extensive ues.In this paper,ILs and DESs are selected to assist synthesis of porous Pt-based bimetallic nanocatalysts.The main research contents are as follows.1.Under the assistance of[C₁₂mim]Cl,porous PtCu bimetallic nanoalloys were simply prepared in aqueous solution at mild temperature?40??.The as-obtained PtCu bimetallic nanoalloys,with the diameter of 40 nm,have mesopoprous structures.The morphology,composition and structures of the as-prepared PtCu nanoalloys were characterized and analyzed in detail by HAADF-STEM,SEM,TEM,XRD and XPS.The effects of the atomic ratio of precursors,reaction temperature and IL structure on the morphology of Pt Cu nanoalloys were investigated.Then,TEM,UV-Vis and FTIR were used to study the growth mechanism of porous PtCu nano-alloys.The prepared porous PtCu nanoalloys showed good electrochemical activity and high stability in the electrocatalytic performance of HCOOH.2.With PVP as stabilizer,porous PtPd bimetallic namomaterials were one-pot synthesized at 90?with the assistance of[C₁₄mim]Br.The as-prepared PtPd namomaterials have the diameter of 35 nm and are composed of many small nanoparticles with 3 nm in diameter.It is shown that the PtPd namomaterials have many interconnected holes with 2-4 nm in diameter,attributing to mesoporous materials.The porous PtPd nanomaterials have rich Pd in central zone and rich Pt in exterior zone,displaying the Pt-on-Pd structures.The results show that the ILs concentrations and atomic ratios of precursors have important influences on the morphology of products.The as-prepared porous PtPd nanoalloys were also investigated as catalysts in the electrocatalytic oxidation of HCOOH.3.Using the newly-developed DESs as solvent,porous Pt Pd and PtCu bimetallic nanoalloys were prepared.In special,the porous PtPd regular hexahedron alloys were one-pot synthesized with the assistance of the DESs composed of choline chloride and formic acid,while porous PtCu spherical nanoalloys with the diameter of 50 nm were obtained with the assistance of the DESs composed of choline chloride and glycol.The products were characterized in detail by HAADF-STEM,SEM,TEM,XRD and EDX.It is found that the DESs concentration,DESs species and atomic ratios of precursors have important effects on the morphology,structures and electrocatalytic performance of the bimetallic nanomaterials.