Development of gas sensor devices incorporating Ni–Cr LDH/TiO₂ through synthesis, characterization, and fabrication processes

Ni–Cr Layered Double Hydroxide/TiO₂ nanocomposite was synthesized by co-precipitation of Ni²⁺ and Cr³⁺, followed by deposition on anatase TiO₂. The nanocomposite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDX). Gas sensing properties of that were studied for ethanol and acetone at room temperature (25 °C). Response of the Ni–Cr LDH/TiO₂ sensor was recorded in the concentration range of 500–5000 ppm of each gas. It was observed that the sensors resistance changes in presence of acetone were descending, and an opposite trend was observed for ethanol. Analysis of the dynamic sensor response at room temperature showed that the maximum response and recovery times in acetone presence are much lower than the corresponding values in the presence of ethanol (4, 25 s vs. 40, 60 s). The sensor response did not change significantly after 20 days, which indicates its acceptable stability.