In present paper, the fusion of metal nanocrystals on TiO2 nanowires is studied and utilized to synthesize bimetallic nanoparticles on nanowires. Cationic polydimethyl aminoethyl methacrylate (PDMAEMA) brushes are grafted onto TiO2 nanowires, and palladium nanocrystals are produced by polymer brush-bound PdCl(4)(2-) and subsequent in situ reduction with NaBH4 in high density and low polydispersity. It is found that Pd nanocrystals of 2-3 nm starts to fuse even at 100 °C, but are apparently obstructed by the polymer brush matrix. Nanocrystal fusion speeds up instantly after polymer decomposition degradation at temperatures above 300 °C. By taking advantage of the polymer brush technique successive, templated uploading of different nanoparticles and fusion, Pd-Au bimetallic nanoparticles or alloys are formed on TiO2 nanowires. The results provide a novel method towards TiO2 nanowire supported (bi)metallic nanoparticles and have hinted at practical uses for elucidating the catalytic behavior of the composites.
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