Nickel Oxide-Carbon Soot-Cellulose Acetate Nanocomposite for the Detection of Mesitylene Vapour: Investigating the Sensing Mechanism Using an LCR Meter Coupled to an FTIR Spectrometer

Abstract

Nanocomposite sensors were prepared using carbon soot (CNPs), nickel oxide nanoparticles (NiO-NPs), and cellulose acetate (CA), which was used to detect and study the sensing mechanism of mesitylene vapour at room temperature. Synthesised materials were characterised using high-resolution transmission electron microscopy (HR-TEM), powder x-ray diffraction (PXRD), Raman spectroscopy, and nitrogen sorption at 77 K. Various sensors were prepared using individual nanomaterials (NiO-NPs, CNPs, and CA), binary combinations of the nanomaterials (CNPs-NiO, CNPs-CA, and NiO-CA), and ternary composites (NiO-CNPs-CA). Among all of the prepared and tested sensors, the ternary nanocomposites (NiO-CNPs-CA) were found to be the most sensitive for the detection of mesitylene, with acceptable response recovery times. Fourier-transform infrared (FTIR) spectroscopy coupled with an LCR meter revealed that the mesitylene decomposes into carbon dioxide.

Selective detection of methanol vapour from a multicomponent gas mixture using a CNPs/ZnO@ZIF-8 based room temperature solid-state sensor

“…3a shows the TEM image of carbon nanoparticles soot, which appears to be spherical with a diameter between 30 and 50 nm. The CNPs soot appears to be stacked on top of each other forming chain-linked spheres obtained from flame pyrolysis, similar findings were reported by L. Malepe et al 36 The ZnO@ZIF-8 nanorods are prepared using the ZnO nanorods and Zn 2+ source. The ZnO nanorods are acting as a template and are coated as a shell with a 2-methylimidazole linker to form ZnO@ZIF-8 nanorods.…”

“…From our previous studies, the CNPs are involved in the total decomposition of VOCs into CO 2 and H 2 O, 68,69 this is due to the presence of reactive O γ and O β reactive species on the surface of CNPs (see Fig. 7b) 36 which are active at room temperature. Reports on the carbon nanomaterials-based sensors indicated that when the sensors are exposed to an electron acceptor such as NO 2 molecules, causes a decrease in the resistance of the sensor 70 and on the contrary when the sensors are exposed to electron donors such as ethanol, the resistance of the sensor increases.…”

“…However, at high temperatures, the O 2 2− and O 2− reactive species become very active and these reactive species tap more electrons as compared to O. 24,35,36…”

“…represents the adsorbed OH on the sensing materials. 36,57 Fig. 7e and f present the peaks at 1021.1 eV and 1044.5 eV assigned for Zn 2p 3/2 and Zn 2p 1/2 respectively, with separating binding energy of about 23.4 eV proving the existence of Zn 2+ in ZnO@ZIF-8 and ZnO@ZIF-8/CNPs composite.…”

“…Besides being an inexpensive and versatile nano-carbon, our previous work with CNPs derived from candle soot in gas sensing has shown that such sensors have an excellent response–recovery times and the ability to work at room temperature. 35–38 The proposed CNPs/ZnO@ZIF-8 nanorods composite can work at room temperatures, possess high sensitivity, selectivity, longer life-span, good reproducibility, fast response–recovery time, and the material can work and reproduce the same results at a wide range of relative humidity. 39…”