One-pot synthesis of plate-like CeO2 nanosheets for sensing NH3 gas at room temperature

Plate-like CeO2 nanosheets were fabricated through a one-pot polyvinylpyrrolidone-assisted polyol process using the cerium–glycolate complex as the precursor at a low reaction temperature, followed by calcination. The morphology, phase composition, crystalline structure, specific surface area, and pore size distributions of plate-like CeO2 nanosheets were analyzed by scanning electron microscopy coupled with energy-dispersive X-ray elemental mapping, X-ray diffractometry, and N2 adsorption–desorption testing. The formation process of plate-like CeO2 nanosheets was discussed in detail. The mesoporous structure of plate-like CeO2 nanosheets synthesized at 50 °C resulted in larger specific surface area of 99.77 m2/g and more pore size of 20 Å than those of were synthesized at 190 °C, which was beneficial to the absorption of NH3 gas. The NH3 gas sensor that was fabricated using the plate-like CeO2 nanosheets synthesized at 50 °C showed a high response (11.8%) even at a low concentration of NH3 of 0.1 ppm, a low detection limit (50 ppb) and good linearity (R2 = 0.9279) over the range of 0.1–100 ppm of NH3 gas at room temperature.