NO_2 gas sensing with SnO_2-ZnO/PANI composite thick film fabricated from porous nanosolid

摘要

SnO_2-ZnO/polyaniline (PANI) composite thick film for NO_2 detection was fabricated from SnO_2-ZnO porous nanosolid and PAN1 by a conventional coating method. The SnO_2-ZnO composite porous nanosolid was prepared by a solvo-thermal hot-press (SHP) method. It was found that the composite sensor has high selectivity and response to low concentration NO_2 gas. Furthermore, the composite sensor also showed high stability to NO_2 over a long working period at low optimum working temperature (180 C). The response and recovery times of SnO_2/PANI composite sensor (SZ20-P) were as short as about 9 and 27 s to 35 ppm NO_2 at 180 ℃, respectively. The experiment results show that both the pore structures of SnO_2 porous nanosolid and the content of ZnO had effects on the sensor response of SnO_2-ZnO/PANI composites, and the optimum content of ZnO was 20 wt.%. The possible sensing mechanism was discussed.