SYNTHESIS OF ZnO/rGO NANOCOMPOSITE FOR NO2 GAS SENSOR

Abstract

Highly sensitive 𝑁𝑂2 gas sensor is demonstrated through 𝑍𝑛𝑂/𝑟𝐺𝑂 nanocomposite at room temperature. 𝑍𝑛𝑂 nanoparticles were hydrothermally synthesized with the help of CTAB. X ray diffraction results proved that 𝑍𝑛𝑂 nanoparticles obtained were highly crystalline in nature. The mixture of 𝑍𝑛𝑂: 𝑟𝐺𝑂 in 10:1, 10:3 and 10:5 (w: w) were produced on the glass substrate through drop-casting method. Then, the samples were annealed at high temperatures. At room temperature, 𝑍𝑛𝑂: 𝑟𝐺𝑂 (10:3) substrate showed remarkable sensitivity of more than 50% for 6ppm of 𝑁𝑂2 gas with response time of less than 1 second. Also, this 𝑍𝑛𝑂: 𝑟𝐺𝑂 composite was highly selective, too, since it did not show any response at all toward other gases like hydrogen sulphide, carbon monoxide and acetone. Also, the reproducibility was good. This is probably due to the enhanced electrical properties of n-type 𝑍𝑛𝑂 and p-type 𝑟𝐺𝑂 interface which leads to better adsorption of 𝑁𝑂2 gas.