Annealing dynamics of WO{sub 3} by in situ XRD

Journal Article · Sat Nov 15 04:00:00 EST 2014 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2014.07.018· OSTI ID:22420621

Righettoni, Marco

Highlights: • Flame-made WO{sub 3} nanoparticles with closely controlled crystal and grain size. • Dynamic phase transition of annealing of pure and Si-doped WO{sub 3} by in situ XRD. • Irreversible evolution of WO{sub 3} crystallinity by heating/cooling during its annealing. • Si-doping alters the WO{sub 3} crystallinity dynamics and stabilizes nanosized WO{sub 3}. • Flame-made nano-WO{sub 3} can sense NO at the ppb level. - Abstract: Tungsten trioxide is a semiconductor with distinct applications in gas sensors, catalysis, batteries and pigments. As such the transition between its different crystal structures during its annealing are of interest, especially for sensor applications. Here, WO{sub 3} nanoparticles with closely controlled crystal and grain size (9–15 nm) and phase composition are made by flame spray pyrolysis and the formation of different WO{sub 3} phases during annealing is investigated. Most notably, the dynamic phase transition and crystal size evolution of WO{sub 3} during heating and cooling is monitored by in situ X-ray diffraction revealing how metastable WO{sub 3} phases can be captured stably. The effect of Si-doping is studied since it is used in practise to control crystal growth and phase transition during metal oxide synthesis and processing. Finally the influence of annealing on the WO{sub 3} sensing performance of NO, a lung inflammation tracer in the human breath, is explored at the ppb-level.

• OSTI ID: 22420621
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Vol. 59; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
CATALYSIS
CRYSTAL GROWTH
CRYSTAL STRUCTURE
CRYSTALS
DOPED MATERIALS
ELECTROCHEMISTRY
GRAIN SIZE
HEATING
NANOPARTICLES
NANOSTRUCTURES
NITRIC OXIDE
PHASE TRANSFORMATIONS
SEMICONDUCTOR MATERIALS
SENSORS
SILICON
SYNTHESIS
TUNGSTEN OXIDES
X-RAY DIFFRACTION