Template-free environmentally friendly synthesis and characterization of unsupported tungsten carbide with a controllable porous framework

Tungsten carbide (WC) with controlled pore size distribution was synthesized using a novel “precursor reassembly” method. The precursor crystal was assembled by mixing ammonium metatungstate (AMT) and ammonium carbonate (AC) in distilled water, followed by hydrothermal treatment. The mesostructure, crystal phase, and amount of deposited graphitic carbon can be conveniently tuned by controlling carburizing atmosphere (CO or a CO/H2 mixture). Moreover, the influence of precursor preparation (AMT/AC mass ratio and hydrothermal temperature) on the materials was also investigated. The resultant materials with low carbon content were mesoporous WCs, which showed high specific surface areas (11.3–20.4 m2 g−1) and adjustable pore-size distributions (average pore size: 15.3–22.3 nm). A mechanism for the formation of WC with a controllable porous framework is proposed. Finally, cyclic voltammetry was used to investigate the inference of different mesoporous structure.

A simple method to fabricate high mesopore volume tungsten carbide (WC) by reassembling of precursor with the assistance of hydro-thermal reaction in ammonium carbonate (AC) is demonstrated. The size of mesopores of WC could be controlled by a combination of hydro-thermal temperature, concentration of AC and carburization atmosphere. This novel method of mesoporous WC synthesis is advantageous over traditional methods because it does not involve the use of additional organic solvents or catalysts.Figure optionsDownload as PowerPoint slideHighlights
► Reconstructed tungstates as mesoporous WC precursors.
► No additional templates, organic solvents or catalysts were used.
► Volatile components enable formation of mesoporous structure.
► Hydrothermal temperature and ammonium carbonate concentration control mesopore size.
► Carburization process can be finished at 800 °C for 2 h.