Nanocomposites of Quasicrystal Nanosheets and MoS<sub>2</sub> Nanoflakes for NO<sub>2</sub> Gas Sensors
Sumit Kumar, Rajneesh Chaurasiya, Shashank Mishra, Partha Kumbhakar, Gang Meng, Chandra Sekhar Tiwary, Krishanu Biswas, Mahesh Kumar
Abstract
Nitrogen dioxide (NO 2 ) is one of the air pollutant gases that harms the environment, human health, and the world ecosystem. The main source of NO 2 emission is the combustion engine, and therefore, it requires a gas-sensing device to monitor the emission. Herein, we report a highly sensitive and selective NO 2 sensor by low-cost and scalable fabrication methods using a hybrid nanocomposite of two-dimensional (2D) Al 70 Co 10 Fe 5 Ni 10 Cu 5 quasicrystal (QC) nanosheets and MoS 2 nanoflakes. The 2D-QC nanosheets combined with MoS 2 nanoflakes form a heterostructure, which improves the gas sensor’s performance. The Al 70 Co 10 Fe 5 Ni 10 Cu 5 /MoS 2 heterostructure showed an excellent gas-sensing response (Δ R / R a %) of ∼66%, which is about 2.27 times higher than that of the pristine MoS 2 nanoflakes-based sensor for 100 ppm NO 2 at 100 °C. In addition, the hybrid nanocomposite gas sensor device also exhibited high selectivity and good sensitivity. The improvement in the gas sensor performance is explained using the density functional theory analysis, which illustrates that the 2D-QC provides a lot of active sites for the adsorption of NO 2 molecules, explained using the adsorption energy, charge difference density, and Bader charges analysis. These gas-sensing results emphasize the significance of the integration of the 2D Al 70 Co 10 Fe 5 Ni 10 Cu 5 QC with MoS 2 nanoflakes, being useful to the design and development of NO 2 -based gas-sensing technology and holding great promise in environmental protection.