Enhanced LPG sensing-performance at room temperature of poly(o-anisidine)–CeO2 nanocomposites†
Abstract
We report a fast-responding and selective room temperature liquefied petroleum gas (LPG) sensor based on poly(o-anisidine)–cerium oxide (POA–CeO2) nanocomposites. The POA–CeO2 nanocomposites were prepared by an in situ chemical oxidative polymerization of o-anisidine in the presence of pre-prepared CeO2 nanoparticles (size ∼5–10 nm). The pre-prepared CeO2 nanoparticles were synthesized by a simple and rapid microwave-assisted method. The POA, CeO2 nanoparticles and their nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). The results of the characterization revealed that interaction occurred between the POA and CeO2 nanoparticles, leading to the formation of POA–CeO2 nanocomposites. The LPG sensing-performance of the nanocomposites was investigated and compared with that of sensors based on POA. The sensor based on a POA–CeO2 nanocomposite with known weight percentage of CeO2 showed better LPG sensing properties than that of pure POA. Upon exposure to 3.4% LPG, the nanocomposite with 30 wt% CeO2 exhibited an enhanced response (∼2.06%), very fast response (∼3–4 s), full recovery within 20 s in air and, most notably, better selectivity at room temperature. Furthermore, the lower detection limit was ∼0.09% which is lower than the permissible explosive limit for LPG. The reproducibility and stability study reveals that these nanocomposites are highly stable. Thus, the combination of the CeO2 nanoparticles and POA offers an attractive selective sensing-performance for LPG at room temperature with fast response/recovery rate.