1.3.1 Suppression of the NO2 interference by Chromium Addition in WO3-Based Ammonia Sensors. Investigation of the Structural Properties and of the Related Sensing Pathways

Mauro Epifani, Pietro Siciliano, Teresa Andreu, Joan R. Morante, Jordi Arbiol, Nuria Garcia-Castello & Joan Daniel Prades
WO3 and Cr-WO3 powders were prepared by sol-gel process, with Cr:W atomic concentration ranging from 2% to 8.8%. WCl6 was used as W precursor and reacted with methanol in presence of acetyacetone as stabilizer. The required amount of Cr 2-ethylhexanoate was then added to the resulting solution, which was then dried. The resulting powder was heat-treated at temperatures ranging from 200 to 700 °C. With increasing the Cr concentration, the samples heat-treated at 500 °C...