<i>Ocimum sanctum</i> Leaf Extract-Assisted Green Synthesis of Pd-Doped CuO Nanoparticles for Highly Sensitive and Selective NO<sub>2</sub> Gas Sensors
Anit K. Ambedkar, Durvesh Gautam, Sagar Vikal, Manohar Singh, Ashwani Kumar, Amit Sanger, Kavita Sharma, Beer Singh, Yogendra K. Gautam
Abstract
High Resolution Image Download MS PowerPoint Slide In view of facile, cost-effective, and environmentally friendly synthetic methods, palladium-doped copper oxide (Pd-CuO) nanoparticles have been synthesized from Ocimum sanctum (commonly known as “Tulsi”) phytoextract for gas-sensing applications. The structural, morphological, and compositional properties of Pd-doped CuO nanoparticles were studied using various techniques such as XRD, FESEM, XPS, and EDX. The characterization results confirmed the doping of Pd on CuO nanoparticles, and Pd-CuO nanostructures appear as nanoflakes in FESEM analysis. The gas-sensing response of Pd (1.12 wt %)-CuO nanoflake-based sensor was measured at 5–100 ppm concentration of different gases, NO 2, H 2 S, NH 3, and H 2, at 125 °C. Gas-sensing tests reveal that the sensitivity of the sensor were 81.7 and 38.9% for 100 and 5 ppm concentrations of NO 2, respectively, which was significantly greater than that of pure CuO. The response and recovery times of the sensor were 72 and 98 s for 100 ppm of NO 2 gas, while they were 90 and 50 s for 5 ppm NO 2 . The calculated limit of detection (LOD) value of the sensor is 0.8235. This appealing LOD is suitable for real-time gas detection. The gas sensor was found to exhibit excellent selectivity toward NO 2 gas and repeatability and stability in humid (80%) conditions. The Pd doping in CuO nanostructures plays a significant role in escalating the sensitivity and selectivity of CuO-based NO 2 gas sensor suitable to work at low operating temperatures.