Heteroatom‐doped polymers or carbon nanospheres have attracted broad research interest. However, rational synthesis of these nanospheres with controllable properties is still a great challenge. Herein, we develop a template‐free approach to construct cross‐linked polyphosphazene nanospheres with tunable hollow structures. As comonomers, hexachlorocyclotriphosphazene provides N and P atoms, tannic acid can coordinate with metal ions, and the replaceable third comonomer can endow the materials with various properties. After carbonization, N/P‐doped mesoporous carbon nanospheres were obtained with small particle size (≈50 nm) and high surface area (411.60 m2 g−1). Structural characterization confirmed uniform dispersion of the single atom transition metal sites (i.e., Co‐N2P2) with N and P dual coordination. Electrochemical measurements and theoretical simulations revealed the oxygen reduction reaction performance. This work provides a solution for fabricating diverse heteroatom‐containing polymer nanospheres and their derived single metal atom doped carbon catalysts.
Heteroatom‐doped polymers or carbon nanospheres have attracted broad research interest. However, rational synthesis of these nanospheres with controllable properties is still a great challenge. Herein, we develop a template‐free approach to construct cross‐linked polyphosphazene nanospheres with tunable hollow structures. As comonomers, hexachlorocyclotriphosphazene provides N and P atoms, tannic acid can coordinate with metal ions, and the replaceable third comonomer can endow the materials with various properties. After carbonization, N/P‐doped mesoporous carbon nanospheres were obtained with small particle size (≈50 nm) and high surface area (411.60 m2 g−1). Structural characterization confirmed uniform dispersion of the single atom transition metal sites (i.e., Co‐N2P2) with N and P dual coordination. Electrochemical measurements and theoretical simulations revealed the oxygen reduction reaction performance. This work provides a solution for fabricating diverse heteroatom‐containing polymer nanospheres and their derived single metal atom doped carbon catalysts.
Four kinds of liquid-like polyhedral oligomeric silsesquioxanes derivatives (liquid-Ds) were fabricated and characterized by FTIR, XPS, TGA, and Rheometer. The liquid-Ds/epoxy nanocomposites were prepared and their thermal resistance properties were tested by TGA. As a result, the thermal resistances properties were improved sharply and influenced by particle sizes, flow abilities, and bonding types of liquid-Ds. The glass transition temperature improved via adding liquid-Ds. The increase of crosslinking density was thought as an important factor to these improvements, which was studied by FTIR spectra and gel content of curved nanocomposites.
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