CeO 2 /Ni-Al layered double hydroxide composite decorated with Ag nanoparticles as a gas sensor

The gas sensing properties of (CeO 2 ) x /Ni-Al LDH composites decorated with Ag nanoparticles (NP) were studied by measuring resistance changes to some important volatile organic compounds (VOCs) such as methanol, ethanol and acetone. The composites were synthesized by hydrothermal, co -precipitation and photoreduction methods. Silver nanoparticles were used in order to increase the surface active sites and subsequently improve the detection sensitivity of pollutants. The microstructure, morphology and electrical properties of the composites were investigated by FESEM, HRTEM, EDS, EDS mapping, XRD, MS, and XPS analyzes. The performance of gas sensors was investigated under stable operating conditions at room temperature (25 degrees C) and relative humidity of 40% at 25-300 ppm of pollutant. The obtained results indicated that the (CeO 2 ) x /Ni-Al LDH composite decorated with Ag had a higher response than (CeO 2 ) x /Ni-Al LDH composite, which was affected by the catalytic effect of Ag. Functional and analytical parameters were measured and analyzed including response/ recovery times, repeatability, stability, selectivity, LOD, LOQ, R 2 and RSD%. Finally, the response mechanism was discussed based on n - n -n heterojunction binding theory.