Oxygen-Vacancy-Enriched Porous α-MoO3 Nanosheets for Trimethylamine Sensing

Two-dimensional ultrathin porous α-MoO3 nanosheets with oxygen vacancies were synthesized by a simple solvothermal method. The thickness of the precursor reaches 14 nm and is accumulated by sheets of 2–6 nm. The pore size is 2–10 nm on the surface. A gas sensor was assembled with the α-MoO3 nanosheets annealed at 400 °C (α-MoO3-400). The sensor based on α-MoO3-400 achieves the fastest response to trimethylamine (TMA) gas at relatively low operating temperature (133 °C). The response of the sensor is 198–50 ppm TMA and the detection limit is 20 ppb. In addition, the sensing mechanism is verified by experiment that the gas molecules adsorb on the surface of MoO3 and participate in the electron transfer of the semiconductor. DFT calculations suggest that MoO3 containing oxygen vacancy can increase charge transfer after TMA adsorbed.