title: Silica-templated synthesis of ordered mesoporous tungsten carbide/graphitic carbon composites with nanocrystalline walls and high surface areas via a temperature-programmed carburization route.
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 degrees 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 degrees C) have potential applications in fuel-cell catalysts and nanodevices.
authors.affiliation: Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Laboratory of Advanced Materials, Fudan University, Shanghai, P. R. China.
authors.forename: Zhangxiong
authors.initials: Z
authors.lastname: Wu
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Yang
authors.forename: Dong
authors.initials: D
authors.lastname: Gu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.forename: Dan
authors.initials: D
authors.lastname: Feng
authors.forename: Zhenxia
authors.initials: Z
authors.lastname: Chen
authors.forename: Bo
authors.initials: B
authors.lastname: Tu
authors.forename: Paul A
authors.initials: PA
authors.lastname: Webley
authors.forename: Dongyuan
authors.initials: D
authors.lastname: Zhao
mesh_terms: D006108:Graphite; D006358:Hot Temperature; D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D057145:Nanoshells / Q000737:chemistry / Q000648:ultrastructure; D036103:Nanotechnology; D053838:Scattering, Small Angle; D012822:Silicon Dioxide; D013499:Surface Properties; D017973:Tungsten Compounds; D014961:X-Ray Diffraction
chemical_list: D017973:Tungsten Compounds; C002802:tungsten carbide; D012822:Silicon Dioxide; D006108:Graphite