Response of a SAW Sensor Array based on Nanoparticles for Measuring Ammonia in the Environment

Four surface acoustic waves (SAW) sensors based on sensitive layers of Fe₂O₃ nanoparticles, pure and combined with noble metals nanoparticles, composed an array sensor to measure ammonia in the environment. The sensor array was tested with nanostructured sensitive layers, which detected the changes of the elastic properties induced by ammonia interaction. The sensor with pure Fe₂O₃ nanoparticles exposed to 50 ppm of ammonia showed no significant effect, however the sensors with Fe₂O₃ nanoparticles combined with Au, Pt and Pd nanoparticles responded to these concentrations of this gas, which is so dangerous for the environment and the health, with a high sensitivity.