SnO Nanoparticles-CeO Nanorods Enriched with Oxygen Vacancies for Bifunctional Sensing Performances toward Toxic CO Gas and Arsenate Ions.

In this paper, we present a novel, one-step synthesis of SnO nanoparticle-CeO nanorod sensing material using a surfactant-mediated hydrothermal method. The bifunctional utility of the synthesized sensing material toward room-temperature sensing of CO gas and low-concentration optosensing of arsenic has been thoroughly investigated. The CeO-SnO nanohybrid was characterized using sophisticated analytical techniques such as transmission electron microscopy, X-ray diffraction analysis, energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and so forth. The CeO-SnO nanohybrid-based sensor exhibited a strong response toward CO gas at room temperature. Under a low concentration (3 ppm) of CO gas, the CeO-SnO sensing material showed an excellent response time of 21.1 s for 90% of the response was achieved with a higher recovery time of 59.6 s. The nanohybrid sensor showed excellent low-concentration (1 ppm) sensing behavior which is ∼6.7 times higher than that of the pristine SnO sensors. The synergistically enhanced sensing properties of CeO-SnO nanohybrid-based sensors were discussed from the viewpoint of the CeO-SnO n-n heterojunction and the effect of oxygen vacancies. Furthermore, the SnO-CeO nanoheterojunction showed luminescence centers and prolonged electron-hole recombination, thereby resulting in quenching of luminescence in the presence of arsenate ions. The photoluminescence of CeO-SnO is sensitive to the arsenate ion concentration in water and can be used for sensing arsenate with a limit of detection of 4.5 ppb in a wide linear range of 0 to 100 ppb.