Multi-Walled Carbon Nanotube-Based Gas Sensor for NH3 Detection at Room Temperature

Gas sensors based on Multi-walled carbon nanotubes (MWNTs) for Ammonia (NH₃) detection at room temperature were studied. MWNT were prepared by chemical vapor deposition method, and coated on Au electrodes, which were sputtered on anodised aluminium substrate and then immersed in thiol solution for 24h. It is found that the MWNT based sensors have a reversible sensing capacity to NH₃ gas with response time and recovery time were less than 1min, respectively. At room temperature of 25°C, resistance changes of the sensor were logarithmic dependent on NH₃ gas concentrations. It is suggested that MWNTs could be a promising sensing material for NH₃ detection at room temperature.