Polyhedrin Assisted Synthesis Of Pd Nanomaterials And Their Electrochemical Catalysis

Palladium nano-materials have been a focus of the research for their own unique properties superior to other materials. People try to use a variety of polymer as stabilizer to control the formation of palladium nano-materials. In this paper, we chose the virus polyhedrin protein as the stabilizer, the assistant reducing agent and the direct agent to control the synthesis of uniform Pd nanoparticle and Pd nanowire networks. The structures, morphologies and properties of samples were characterized by a series of testing methods. Also, the inter-action between the virus polyhedron and the palladium ions has been studied. The details and results are summarized as follows:The irregular shape virus polyhedrin protein of nanometer size has been obtained after alkaline hydrolysis and purify. Pd nanoparticles and Pd nanowire networks have been synthesized by incubating viral polyhedrin with different concentrations of palladium salt solution. The prepared palladium nanoparticles have a small size(ca. 3.3 nm) and size distribution, and disperse uniformly. The single diameter of the prepared palladium nanowire networks is about 3.5 nm.By the contrast test with water and different p H value in the process of incubation experiment, the action of the viral polyhedrin in the preparation of palladium nano-materials and the optimum conditions as a stabilizer were explored. The optimal concentration of palladium ion for synthesis Pd nanoparticles and Pd nanowire networks was confirmed by changing the concentration parameter in the experiments. The disciplinary of nano-materials changing with the different concentration of palladium ion and the stability of the nano-materials were summarized.The electrochemically active surface area and catalytic effect to alcohols in the alkaline solution of the Pd nano-materials have been discussed. The results showed that, the first peak current density of Pd nanoparticles(5.646 m A·cm-2)for the methanol oxidation is 324.5% higher than that of the commercial Pd/C(1.33 m A·cm-2). The initial potential of Pd nanowire networks for ethanol oxidation is 60 m V earlier than the commercial Pd/C. The peak current density(9.80 m A·cm-2) of Pd nanowire networks is 3 times higher than that of the commercial Pd/C(3.30 m A·cm-2).