Colloidal Polymerization of Polymer-Coated Ferromagnetic Nanoparticles into Cobalt Oxide Nanowires

Abstract

The preparation of polystyrene-coated cobalt oxide nanowires is reported via the colloidal polymerization of polymer-coated ferromagnetic cobalt nanoparticles (PS-CoNPs). Using a combination of dipolar nanoparticle assembly and a solution oxidation of preorganized metallic colloids, interconnected nanoparticles of cobalt oxide spanning micrometers in length were prepared. The colloidal polymerization of PS-CoNPs into cobalt oxide (CoO and Co(3)O(4)) nanowires was achieved by bubbling O(2) into PS-CoNP dispersions in 1,2-dichlorobenzene at 175 degrees C. Calcination of thin films of PS-coated cobalt oxide nanowires afforded Co(3)O(4) metal oxide materials. Transmission electron microscopy (TEM) revealed the formation of interconnected nanoparticles of cobalt oxide with hollow inclusions, arising from a combination of dipolar assembly of PS-CoNPs and the nanoscale Kirkendall effect in the oxidation reaction. Using a wide range of spectroscopic and electrochemical characterization techniques, we demonstrate that cobalt oxide nanowires prepared via this novel methodology were electroactive with potential applications as nanostructured electrodes for energy storage.

Ni and/or Co nanoparticles as catalysts for oxygen reduction reaction (ORR) at room temperature

“…Recently, the synthesis of polystyrene coated cobalt oxide nanowires [43] was reported, which attracted our interest as a potential material for ORR. However, due to the results reported above, the polymer was thought to prevent any metal/oxide activity and no further attempts were made.…”

Synthesis and Solution Self‐Assembly of Polyisoprene‐block‐poly(ferrocenylmethylsilane): A Diblock Copolymer with an Atactic but Semicrystalline Core‐Forming Metalloblock

“…The resulting building blocks can be used for the preparation of complex hierarchical structures. [371][372][373][374][375][376] For example, PFS homopolymer can be used to aggregate short BCP cylindrical micelles into networks. 349 End-to end coupling of two or more micelles gave linear, linked or branched structures depending on the composition of the BCP micelle and the PFS polymer added.…”

High precision NH3 sensing using network nano-sheet Co3O4 arrays based sensor at room temperature

“…Development of novel nanostructured transitional metal oxides with controlled shapes and morphologies has stimulated considerable research interest due to their novel physical and chemical properties and potential wide-range applications [26][27][28]. So far, various morphological nanostructures of Co3O4 have been explored, including nanoparticles [19], nanofiber [20], nanowires [17,[29][30][31], nanotube [15,16], nanobelt [32], nanorods [13,23,24], and nano-sheets [18,33,34] using various methods including thermal oxidation, hydrothermal synthesis, electrospinning and inverse microemulsion. Co3O4 nano-sheets grown directly on substrates should have excellent sensing performance because the interconnected nano-sheets will form a network porous nanoscale system which facilitates a fast and effective gas adsorption onto the entire sensing surface, thus significantly improving sensitivity and reducing the response time.…”