Conductometric NOx sensor based on exfoliated two-dimensional layered MnPSe3

Abstract Nitrogen dioxide (NO2) and nitric oxide (NO) collectively called NOx are toxic gases which are emitted during combustion process. Selective detection of NOx at low concentration is essential for human health and environment monitoring. The present study has explored the use of 2D few-layer manganese phosphoselenide (MnPSe3) towards selective and reversible NOx (NO2 and NO) sensing under ambient conditions. Few layer MnPSe3 obtained by solvent exfoliation of bulk material is used as uniform thin film for NOx gas sensing. The sensor shows responses of 685% and 137% for the detection of 1 ppm of NO2 and NO gas respectively. The total NOx (sum of NO and NO2) at different ratios of the constituents can be detected as well. The response follows Langmuir-type behavior with high selectivity towards NOx-based gases in presence of H2, O2, CO, CO2 and C2H2. The sensor is completely reversible with fast response and recovery times under ambient conditions. Temperature dependent studies indicate that the sensor response increases upto a certain temperature and then decreases in presence of humidity. The effect of humidity is studied as well.