Simple, green self-construction approach for large-scale synthesis of hollow, needle-like tungsten carbide

• Published in: Powder technology 2013-02, Vol.235, p.467-474
• Main Authors: Chen, Zhao-Yang, Shi, Mei-Qin, Ma, Chun-An, Chu, You-Qun, Zhu, Ai-Juan
• Format: Article
• Language: English
• Subjects: Adsorption; Applied sciences; Carburizing; Catalysis; Catalytic reactions; Chemical engineering; Chemistry; Crystals; desorption; Evolution; Exact sciences and technology; Expansion; General and physical chemistry; hydrogen; Hydrogen sorption; Mesoporosity; Millimeter particles; Miscellaneous; Reactors; Self assembly; Self-construction; Solid-solid systems; Specific surface; surface area; Synthesis; temperature; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Tungsten carbide; volatilization
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2012.10.013

A self-assembly process prepared needle-like crystals at room temperature. Calcination and temperature-programmed carburization processes facilitated an evolution of the as-prepared crystals into hollow, needle-like mesoporous tungsten carbide (WC). This synthesized, large-sized (approximately 3mm) WC exhibited a highly specific surface area (9.74m2/g). Moreover, the mesopores were centered at 20.2nm for its advanced formation, and these could further enlarge to 34.2nm via direct carburization. The successful synthesis of the materials is associated with the formation of a pre-assembled precursor with increased volatilized components and needle-like structure. Various pore evolutions during the synthesizing processes were discussed to explain the formation of mesostructures. The H2 adsorption/desorption highly improves with the introduction of the mesoporous structure. The synthesized, needle-like WCs with mesoporous structure may be potential candidates for catalytic and adsorptive applications. A self-assembly process prepared needle-like crystals at room temperature without any organic solvents. Hollow needle-like mesoporous WC powders (length: ~3mm) were prepared by a subsequent traditional carburization processes. Resultant WC exhibited highly specific surface area and controllable mesoporous structure, which result in high activity for H2 adsorption/desorption. [Display omitted] ► Millimeter-sized crystal was self-assembled in aqueous solution at room temperature. ► Hollow, needle-like and millimeter-sized WC with mesoporous structure was prepared. ► The pore size distribution of WC is tunable via different carburization processes. ► No complicated equipments, organic solvents and organic/inorganic templates were used. ► Carburization routes control pore distribution.