Industrial grade tungsten trioxide refers to a type of yellow powder with an average particle size of less than 100 nm, a specific surface area of more than 9m^2/g and a purity of more than 99.95%. It is produced by using Chinese standard. It adopts ammonium paratungstate (APT) as raw material. It is widely applied in the production of petroleum catalysts, special paints, metal ceramics and ultrafine tungsten powder. Its CAS number is 1314-35-8.
Preparation
Adopting ammonium metatungstate (AMT) as tungsten source and citric acid as morphology control agent, the nano tungsten trioxide is synthesized by hydrothermal method. Under the conditions of ethanol, acetone, ammonia and formaldehyde, gas sensitivity tests on tungsten trioxide gas sensors are made. These tungsten trioxide gas sensors are nano-rod type, nano-plate type and nano-bar type.
The results show that the nano-plate type tungsten trioxide gas sensor has the highest sensitivity compared with the other two kinds of gas sensors. And nano-plate type one is very sensitive to low concentrations of ammonia.
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