Lychee-like Bi₂MoO₆ Spheres for Highly Sensitive Room-Temperature Phosphine Sensing

The increasing use of phosphine in various industries demands the development of reliable sensors. However, progress in this area has been slow, particularly for room-temperature detection. In this study, bismuth molybdate microspheres with a lychee-like structure (Lyc-Bi₂MoO₆) were prepared via a one-step solvothermal method, which can be employed for the detection of trace concentrations of phosphine. The solvent used was a mixture of isopropanol and ethylene glycol in a 3:1 ratio. Various characterization techniques and gas sensing performance tests demonstrated that Lyc-Bi₂MoO₆ is a potential phosphine-sensing material for room-temperature application. Sensing performance tests revealed that Lyc-Bi₂MoO₆ exhibited an impressive ability to detect trace concentrations of phosphine, with a practical detection limit as low as 150 ppb (response = 8.11), rapid response (around 1 min), and excellent long-term stability (a maximum response attenuation of 9.46% over 10 weeks). Density functional theory calculations further aided in the in-depth analysis and interpretation of the behavior and response mechanism of phosphine on the surface of Lyc-Bi₂MoO₆.