Reduced graphene oxide (rGO) decorated ZnO-SnO2: A ternary nanocomposite towards improved low concentration VOC sensing performance

A ternary p-n-n heterojunction has been prepared by introducing reduced graphene oxide (rGO) in ZnO-SnO2 nanocomposite and its ppm level volatile organic compounds (VOCs) sensing properties have been exploited. Using a simple, facile sol-gel process, initially, ZnO-SnO2 nanocomposites containing different concentrations of ZnO and SnO2 were prepared and subsequently this was followed by rGO incorporation. The as-synthesized powders were well characterized through XRD, FTIR, Raman spectroscopy, FESEM, TEM, and XPS analyses. The sensing study revealed that, the ternary nanocomposite sensor delineated similar to 91% n type sensing response towards similar to 10 ppm acetone gas at an optimum working temperature of 150 degrees C. Even it could sense similar to 1 ppm acetone with appreciable sensing response of similar to 71%. Additionally, the sensor displayed fast response (similar to 10 s) and recovery time (similar to 100 s) suitable for detection of multiple pulses in short time duration. It also exhibited a considerable similar to 65% sensing response towards similar to 10 ppm ethanol at 150 degrees C. These superior sensing performances of rGO decorated ZnO-SnO2 nanocomposite illustrated with band structure modification. Our results indicated that, the fabricated rGO decorated ZnO-SnO2 sensor, with remarkable high sensing response, minimum interference from other toxic, inflammable gases and profound long term stability, could be considered as a prolific candidate for real time detection of low concentration VOCs in versatile commercial applications. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

A ternary p-n-n heterojunction nanocomposite sensor with rGO decoration showed high sensitivity towards ppm level VOCs like acetone and ethanol at 150 degrees C, with fast response and recovery times suitable for real-time detection of low concentration VOCs in versatile commercial applications. The sensor demonstrated remarkable sensing response, minimum interference from other toxic gases, and long-term stability.