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

Abstract

In this paper, we present a novel, one-step synthesis of SnO2 nanoparticle–CeO2 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 CeO2–SnO2 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 CeO2–SnO2 nanohybrid-based sensor exhibited a strong response toward CO gas at room temperature. Under a low concentration (3 ppm) of CO gas, the CeO2–SnO2 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 SnO2 sensors. The synergistically enhanced sensing properties of CeO2–SnO2 nanohybrid-based sensors were discussed from the viewpoint of the CeO2–SnO2 n–n heterojunction and the effect of oxygen vacancies. Furthermore, the SnO2–CeO2 nanoheterojunction showed luminescence centers and prolonged electron–hole recombination, thereby resulting in quenching of luminescence in the presence of arsenate ions. The photoluminescence of CeO2–SnO2 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.