3D flower-like NiCo-LDH composites for a high-performance NO2 gas sensor at room temperature

Abstract

Excellent response with a fast response/recovery time, as well as good repeatability and longtime stability, are considered to be advantageous features of an ideal gas sensor. To this purpose, in this paper, uniform 3D flower-like layered nickel-cobalt layered double hydroxide (NiCo-LDH) composites were prepared by a simple hydrothermal method. The gas sensing performance of the NiCo-LDH NO2 gas sensors was investigated at room temperature (RT). Among the composites, Ni1Co1 (Ni/Co molar ratio = 1:1) shows a high response of 31.22 at 100 ppm with fast response and recovery times equal to 1.6 s and 11.6 s, respectively. Similarly, the Ni1Co1 sensor indicates a low detection limit of only 0.01 ppm (10 ppb) and shows excellent stability (60 days) and high selectivity to NO2. The NiCo-LDH sensor has excellent NO2 gas sensitivity performance due to its a high specific surface area or Co(OH)2 and Ni(OH)2 synergy. Therefore, we believe that Ni/Co-LDH sensors can be widely used in the field at RT and have good development prospects.