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Silica‐Templated Synthesis of Ordered Mesoporous Tungsten Carbide/Graphitic Carbon Composites with Nanocrystalline Walls and High Surface Areas via a Temperature‐Programmed Carburization Route
Author(s) -
Wu Zhangxiong,
Yang Yunxia,
Gu Dong,
Li Qiang,
Feng Dan,
Chen Zhenxia,
Tu Bo,
Webley Paul A.,
Zhao Dongyuan
Publication year - 2009
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.200900523
Subject(s) - materials science , carburizing , nanocrystalline material , tungsten carbide , carbide , carbon fibers , mesoporous material , sintering , chemical engineering , carbonization , tungsten , mesoporous silica , nanoparticle , phase (matter) , specific surface area , composite material , catalysis , nanotechnology , metallurgy , composite number , scanning electron microscope , organic chemistry , chemistry , engineering
Abstract Ordered mesostructured tungsten carbide and graphitic carbon composites (WC/C) with nanocrystalline walls are fabricated for the first time by a temperature‐programmed carburization approach with phosphotungstic acid (PTA) as a precursor and mesoporous silica materials as hard templates. The mesostructure, crystal phase, and amount of deposited graphitic carbon can be conveniently tuned by controlling the silica template (SBA‐15 or KIT‐6), carburizing temperature (700–1000 °C), the PTA‐loading amount, and the carburizing atmosphere (CH 4 or a CH 4 /H 2 mixture). A high level of deposited carbon is favorable for connecting and stabilizing the WC nanocrystallites to achieve high mesostructural regularity, as well as promoting the carburization reaction. Meanwhile, large pore sizes and high mesoporosity of the silica templates can promote WC‐phase formation. These novel, ordered, mesoporous WC/C nanocomposites with high surface areas (74–169 m 2 g −1 ), large pore volumes (0.14–0.17 cm 3 g −1 ), narrow pore‐size distributions (centered at about 3 nm), and very good oxidation resistance (up to 750°C) have potential applications in fuel‐cell catalysts and nanodevices.