Abstract TiO 2 nanoparticles can exhibit benefits in various areas, including physics, chemistry, biology, the environment, and agriculture, among others, for the advancement of the world. In this research work, TiO 2 nanomaterials are fabricated using a green synthesis technique called mechanical attrition and analysis of their properties for CO gas sensors. The structural study confirmed the stable tetragonal crystal structure for TiO 2 samples, reducing the crystallinity and forming defects at higher milling times. The morphological analysis showed the transformation of larger grains (more than 1 μm) to nano-sized grains (around 100 nm) after 10 h of the milling process, verifying the formation of nanoparticles. The decrease in oxygen content (at.%) was found with an increase in milling time, creating oxygen vacancies and defects in the crystal structure. Moreover, the bandgap values of the TiO 2 samples were calculated using reflectance data, where the increment in the bandgap value from 2.83 to 3.22 eV was attributed to decrement of structural parameters. Raman and FTIR spectra of TiO 2 samples reveal an increase in structural defects and lattice disorder with increasing milling times. From BET analysis, greater surface area and pore volume were found for milled samples, which leads to improved interaction with other materials at the molecular level. Nano-sized TiO 2 samples allow more interaction with the target gas due to their high surface area, and finally, improve the CO gas sensing response for milled TiO 2 samples. Therefore, the investigation related to TiO 2 nanoparticles using the mechanical attrition made up of agate materials is promising in CO gas sensing applications. Graphical abstract
Adhikari et al. (Fri,) studied this question.