Synthesis and characterization of ZnO-MWCNT nanocomposites for 1-butanol sensing application at room temperature

• Published in: Physica. B, Condensed matter Condensed matter, 2019-10, Vol.570, p.139-147
• Main Authors: Bhat, Pratima, K, Naveen Kumar S., Nagaraju, P.
• Format: Article
• Language: English
• Subjects: Band gap; Butanol; Chemical synthesis; Crystallites; Detection; Functionalized MWCNT; Gas sensor; Gas sensors; Microstructure; Morphology; Multi wall carbon nanotubes; Nanocomposites; Nanotubes; Optical properties; Organic chemistry; Recovery time; Response time; Room temperature; Sensitivity; Volatile organic compound; Wurtzite; Zinc oxide; Zinc oxides
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2019.06.008

Zinc oxide and multiwall carbon nanotubes ZnO/(MWCNT) composites were synthesised using wet chemical method and annealed at 400 °C for 1 h. They were studied for their microstructure, morphology, optical, electrical and gas sensing properties. SEM analysis showed uniform hexagonal disc like structure of ZnO within the fibers of MWCNT. XRD pattern indicated that the crystalline nature of the sample with hexagonal wurtzite phase. The crystallite size was reduced due to the increased MWCNT concentration. Optical band gap was determined using Tauc's plot. It was decreased from 3.12eV to 2.97eV with increasing MWCNT concentration. FTIR spectra confirmed the Zn–O stretching and carboxylic group in the ZnO composite samples. I–V curve showed the ohmic nature of sample. 1-butanol sensing properties were studied at the room temperature of 27 °C in static mode. Experiment results indicated a highest sensitivity with ZnO at 500 ppm. Whereas ZnO/MWCNT composite sensor showed faster response and recovery times. •Synthesised particles are studied for their microstructure, morphology, optical and electrical characteristics.•A uniform hexagonal disc like ZnO structure is obtained with few pores due to annealing at high temperature (4000C). The MWCNT fibers surrounding the ZnO provides a path for electron conduction.•Gas sensing study at room temperature (270 C) towards the target gas (1-butanol) at various ppm levels (50ppm -500 ppm) showed a better sensitivity (5.1) for pure ZnO as compared to ZnO/MWCNT nano composites. But ZnO/MWCNT nano composites showed faster response and recovery time (∼10 sec and 18 sec) at 100 ppm.