Porous 3D flower-like CoAl-LDH nanocomposite with excellent performance for NO₂ detection at room temperature

The 3D flower-like CoAl-layered double hydroxide (CoAl-LDH) was successfully prepared using the functional template agent of fluoride ions via a facile one-step hydrothermal route. Various techniques proved that all the samples presented 3D flower-like microstructural morphology. Representatively, the CA-2 sample, which was synthesized with the molar ratio of Co : Al of 3.65 : 1, had considerably abundant pores in its thin nanosheets. The average pore size was 2-4 nm, the specific surface area was equal to 49.45 m² g^-1, and the thickness of nanosheets was approximately 3.068 nm. The CA-2 sample showed an excellent response to 0.01-100 ppm NO₂ with ultrafast response/recovery time at room temperature (RT). The detection limit of the sensor even reached 10 ppb. The superior gas sensing performance could be attributed to the synergistic effects of the functional template agent of fluoride ions and specific porous 3D flower-like nanostructure. The current study showed that the 3D flower-like CoAl-LDHs might a promising material in practical detection of NO₂ at RT.