Enhanced Physico‐Chemical and Electrical Characteristics of Hydrothermally Synthesized NiTiO <sub>3</sub> via Tungsten Doping for Gas Sensing Applications
Manoj A. More, Sarika D. Shinde, Nithesh Naik, Fabian I. Ezema, Huda I. Ahemad, G. H. Jain, Dnyaneshwari Y. Patil, Sharad B. Patil, Ji Man Kim, Ravindra N. Bulakhe, G. E. Patil
Abstract
Herein, tungsten-doped nickel titanate (WNiTiO3) nanoparticles are synthesized using hydrothermal route and investigated physicochemical and gas sensing properties. The effect of W-dopant concentrations on the physicochemical and electrical characteristics of NiTiO3 is systematically investigated. X-ray diffraction analysis revealed a consistent decrease in crystallite size, accompanied by an increase in dislocation density and micro-strain with higher W doping levels. Optical study demonstrated significant band-gap narrowing (2.90 to 2.78 eV) due to tungsten incorporation. Fourier-transform infrared and Raman spectroscopies confirmed the W substitution at Ti sites. Surface morphology studies revealed the reductions in particle size and enhancements in the surface-to-volume ratio due to W doping. Thermo gravimetric analysis confirms enhanced thermal stability with increased W content. Electrical measurements show increased resistance in doped samples, which is indicative of charge carrier scattering and lattice distortion effects. Gas sensing analysis showed a significant improvement in H2S sensing performance with doping. The 10 mm W-doped NiTiO3 sensor exhibits the highest response of 88.66 at 250 °C for 100 ppm H2S, along with a rapid response (20 s), quick recovery (26 s) times, exceptional selectivity, and stable performance over 60 days, underscoring its potential for practical applications.