Sinter-Necked, Mixed Nanoparticles of Metallic Tungsten and Tungsten Oxide Produced in Fuel-Rich Methane/Air Tubular Flames

抄録

Metallic tungsten nanoparticles have attracted considerable attention because of their unique structures and excellent performances. This paper describes the synthesis of a mixture of tungsten metal and oxide nanoparticles via a fuel-rich tubular flame process, followed by mild-reduction-based post-heating treatment. The high combustion efficiency of the tubular flame process enables complete consumption of O₂ in the premixture, along with the emission of CO and H₂. The experimental results revealed that the tubular flames produced mixtures of amorphous tungsten oxide and crystalline tungsten nanoparticles with primary particle sizes of 5–10 nm, at a production rate of 4.68 mg/h and yield of 8.64%. These nanoparticles exhibited a sinter-necked structure. The oxygen content of the tubular-flame-synthesized mixtures of tungsten metal and oxide nanoparticles (16.80%) to 5.56% after the additional post-heating treatment, which also retained the particle size.