Study On The Preparation And Catalytic Performance Of Carbon-supported Bimetallic Nano-particle Composites

The precious metal nanomaterials have extensive application in fuel cells.Especially,Pt is anode and cathode reaction catalyst in many fuel cells.However,the price of Pt greatly increases the cost of fuel cells,and its storage greatly limits its commercial development.So finding Pt-alternative electrocatalyst and improving the performance of catalyst are major issues for fuel cells.Pd,Rh and Pt are commen noble metals,Cu,Fe,Ni,Co and also very common and cheap metals in our life.In this paper,we focus on synthesizing carbon-supported nobel-cheap alloy,and investigate their catalytic performance for fuel molecules oxidation reaction.The main results obtained are as follows:1.We develop a surfactant-free co-precipitation/co-reduction method to synthesize graphene-supported nanocrystalline PdCu(PdCu/GN)hybrids with high alloying degree.The strong interaction between graphene oxide and metal hydrates results in uniform precipitation on the graphene oxide surface,which plays a critical role in excellent dispersion and high alloying degree of PdCu nanocrystals.Cyclic voltammetry and chronoamperometry measurements show that nanocrystalline PdCu/GN hybrids have higher activity and durability than commercial Pd/C catalyst for the formic acid oxidation reaction.2.We synthesize carbon ball-supported RhCo alloy nanocrystals(RhCo/CB)nanohybrids with different Rh/Co atomic ratios,and investigate their electrocatalytic acitvity for the MOR in alkaline media.Cyclic voltammetry and chronoamperometry measurements show Rh3Co1/CB nanohybrids have exceptional electrocatalytic activity and long-term stability for the MOR in alkaline media,much higher than commercial Pd/C and Pt/C electrocatalysts,demonstrating that Rh-based alloy nanocrystals may be highly promising Pt-alternative electrocatalyst for the MOR in alkaline media.3.We synthesize carbon bowl supported Pd-Co alloy(Pd2Co1/CWs)by cyanogel autoreduction method.The as-prepared Pd2Co1/CWs are detailedly characterized by various physical techniques,such as transmission electron microscopy,X-ray photoelectron spectroscopy,X-ray diffraction,and element mapping,etc.Scanning electron microscopy and transmission electron microscopyanalys showed that the prepared Pd-Co nanoparticles were small cubes and uniformly distributed on the carbon nanobowl support with a mean particle size of 10.3 nm.Meanwhile,the electrochemical property of Pd2Co1/CWs was examined by cyclic voltammetry and chronoamperometry measurements.Compared with commercial Pd/C and Pt/C electrocatalyst,the optimal Pd2Co1/CWs display a remarkably enhanced electrocatalytic performance for the EOR in alkaline media.The superior catalytic activity of Pd2Co1/CWs suggests it to be as a promising electrocatalyst for the direct ethanol fuel cells.