MoS2-Templated Porous Hollow MoO3 Microspheres for Highly Selective Ammonia Sensing via a Lewis Acid-Base Interaction

The development of a high-performance sensing material for the detection of ammonia gas is of significant importance due to its wide industrial presence and potential hazard risks. In this article, we report the synthesis of porous and hollow MoO3(p-h-MoO3) microspheres via the oxidation of MoS2microsphere templates, which are obtained via self-assembly of MoS2nanosheets under hydrothermal conditions. The composition and morphology of the p-h-MoO3microspheres are systematically characterized via microscopic and spectroscopic techniques, and our sensing tests reveals that p-h-MoO3possesses ultrahigh responsiveness to ammonia gas, which can be further optimized via the selection of a suitable oxidation temperature and time. Additionally, the p-h-MoO3shows minimal responses to other gaseous molecules, thereby demonstrating significant selectivity toward ammonia. The sensing mechanism of p-h-MoO3toward ammonia is further investigated to identify the origin of its ultrahigh sensitivity and selectivity via X-ray photoelectron spectroscopy and diffuse reflectance Fourier transform infrared spectroscopy.