Improved Ethanol Sensing Performance of α-MnO₂ Nanorods at Room Temperature Enabled through PPy Embedding

Abstract

Ethanol is a colorless, highly flammable, volatile organic compound and is a biomarker for fatty liver diseases. So, high-performance and reliable ethanol sensors are the need of the day for biomedical and environmental monitoring applications and drunken driving detection. In this work, we have reported a polypyrrole (PPy)-embedded α-MnO 2 nanorod (NR)based chemiresistive sensor for the selective detection of trace ethanol vapor at room temperature (25 °C). PPy-embedded α-MnO 2 NR nanocomposites (MP25, MP50, and MP100) were synthesized by in situ chemical oxidative polymerization of pyrrole followed by mixing of α-MnO 2 NR having different weight ratios. The prepared nanocomposites were characterized by various sophisticated instruments such as XRD, FTIR, Raman spectroscopy, BET, FESEM, TEM, EDX, UV−vis spectroscopy, and current−voltage (I−V) measurement. The as-prepared sensor, namely, PPy-embedded α-MnO 2 nanorod (MP50), shows the highest response to ethanol vapor with a detection lower limit of 1 ppm at room temperature with rapid response (∼2.39 s) and recovery (∼37.08 s) times associated with at least 60 days stability, excellent selectivity, good repeatability, and reproducibility. The formation of a p−n heterojunction and transfer of charge carriers between PPy and MnO 2 nanoparticles are attributed to the enhancement of sensing performance. Thus, the prepared sensor could be potentially applicable to detect ethanol content in alcoholic beverages, diagnose liver disease from exhale breath analysis, and drunken driving detection. Recently, conducting polymers such as polypyrrole (PPy),