Transition metals Fe3+, Ni2+ modified titanium dioxide (TiO2) film sensors fabricated by CPT method to sense some toxic environmental pollutant gases

Abstract The present investigation deals synthesis of undoped TiO2, Ni2+ doped TiO2, and Fe3+ doped TiO2 nanoparticles by low-cost co-precipitation (CPT) method. The thick film sensors of all the fabricated modified TiO2 nanoparticles were designed by a screen printing strategy. The prepared thick film sensors were characterized by various sophisticated techniques. The structural parameters of undoped TiO2 and modified TiO2 film sensors were characterized by X-Ray Diffraction (XRD) which confirmed anatase phase of TiO2 lattice. The surface morphological properties of all the prepared materials were confirmed by means of scanning electron microscope (SEM). The energy dispersive spectroscopy (EDS) confirms the elemental composition of all the prepared materials. High-Resolution Transmission Electron Microscopy (HR-TEM) was utilized to investigate the crystal lattice of fabricated TiO2 material. The HR-TEM results revealed the anatase phase crystal morphology of prepared material. The prepared TiO2 materials were also characterized by means of X-Ray photoelectron spectroscopy (XPS) to confirm the surface doping, specific biding energies, chemical states and elemental composition of modified TiO2 materials. The Brunauer–Emmett–Teller (BET) study was carried to investigate the specific surface area of all the prepared sensors. The Fe3+ doped TiO2 sensor found with enhanced surface area (83.10 ​m2/g) in comparison to Ni2+ doped TiO2 and bare TiO2 (67.34 ​m2/g). All the prepared materials were investigated for gas sensing characteristics. The NO2, SO2, and CO2 gases were investigated for all the prepared sensors. The reusability test confirms that the Fe3+ doped TiO2 is reproducible and stable sensor for long time repeated sensing of SO2 and NO2 vapors. Importantly, Fe3+ doped TiO2 sensor showed rapid response and recovery towards SO2 and NO2 vapors.