Highly selective and sensitive ammonia sensor using polypyrrole/V2O5 composites

In the present study, polypyrrole (PPy) and its composite with V2O5 were synthesized via a modified chemical oxidation polymerization method. The resultant materials were characterized by FT-IR, XRD and LCR-meter techniques. The FT-IR results confirmed the successful synthesis of PPy and PPy/V2O5 composites. The XRD studies illustrated the amorphous and crystalline nature of PPy and PPy/V2O5 composites, respectively. The electrochemical ammonia sensing behavior of the synthesized materials was evaluated using LCR-meter. The sensitivity of the materials towards ammonia was studied with respect to V2O5 content in the composites, temperature and ammonia concentration. Among the studied materials, PPy/V2O5 composite with 8 wt.% of V2O5 showed best sensitivity response toward ammonia at 25 A degrees C in the range of 5-200 ppm with limit of detection of 1.4 ppm. The sensitivity, response and recovery times of PPy/8 wt.%V2O5 determined from dynamic response curve at 10 ppm ammonia were 19.5%, 10.5 and 81.6 s, respectively. The highly selective ammonia sensing performance of PPy/V2O5 composites may be due the incorporation of V2O5 in PPy and could be declared as a promising candidate for sensitive gas sensors.