On a P-type Ammonia Gas Sensor Prepared by a Copper Oxide Thin Film Functionalized with Platinum Nanoparticles

A new and interesting p-type ammonia (NH3) gas sensor, utilizing a sputtered copper oxide (CuO) thin film along with evaporated platinum nanoparticles (Pt NPs), is fabricated and investigated. The employment of Pt NPs can effectively enhance the NH3 gas sensing performance. A series of analyses are employed to study the basic elemental, morphological, and compositional characteristics. The relevant NH3 gas sensing mechanism is elucidated in this study. In experiments, the Pt NP/CuO sensor shows a high sensing response of 12.2 (3.25), along with response time and recovery time of 249 s (315 s) and 47 s (186 s) under 1000 ppm (100 ppm) NH3/air gas at 300℃. Also, an extremely lowest detectable level of 10 ppb NH3/air is found at 300℃. In addition, the studied sensor demonstrates promised reproducibility and selectivity toward NH3 gas. Based on a study of kinetic adsorption, the activation energy of 24.68 kJ mol-1 is found for the studied sensor. The studied Pt NP/CuO sensor demonstrates a straightforward device structure, ease of production, a widespread sensing range (10 ppb to 1000 ppm NH3/air), and cost effectiveness.