SnO₂ Nanoparticles–CeO₂ Nanorods Enriched with Oxygen Vacancies for Bifunctional Sensing Performances toward Toxic CO Gas and Arsenate Ions

High Resolution Image Download MS PowerPoint Slide In this paper, we present a novel, one-step synthesis of SnO 2 nanoparticle–CeO 2 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 2 –SnO 2 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 2 –SnO 2 nanohybrid-based sensor exhibited a strong response toward CO gas at room temperature. Under a low concentration (3 ppm) of CO gas, the CeO 2 –SnO 2 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 2 sensors. The synergistically enhanced sensing properties of CeO 2 –SnO 2 nanohybrid-based sensors were discussed from the viewpoint of the CeO 2 –SnO 2 n–n heterojunction and the effect of oxygen vacancies. Furthermore, the SnO 2 –CeO 2 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 2 –SnO 2 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.