A Rapid ppb Level Room Temperature NO₂ Sensing by Using BiVO₄–CeO₂ Composites with DFT Interpretation

Abstract

This study describes the successful synthesis of a series of bismuth vanadate and ceria nanocomposites (BiVO 4 − CeO 2 ). The surface morphology, chemical composition, and sensing properties of as-synthesized samples have been analyzed using X-ray diffraction analysis (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray photoelectron spectrometer (XPS), and ultraviolet−visible light (UV−vis) spectrometer. Moreover, during gas sensing measurements, the gas sensor based on BiVO 4 −CeO 2 (1:1) demonstrated the best gassensing properties for nitrogen dioxide (NO 2 ) at room temperature, including a high response value (17 toward 1 ppm), fast response time (37 s toward 1 ppm), rapid recovery time (31 s toward 1 ppm), and ultralow detection limit (0.05 ppm). This may be explained by its superior structural characteristics, increased absorption capacity, and the synergistic effect of heterojunction. In addition, calculations based on the density function theory (DFT) were performed to validate the experimentally observed results. The variation in the different energy levels of the BiVO 4 −CeO 2 nanocomposite validates the gas sensing mechanism and charge transfer during gas interactions.

Theoretical Investigation of TiSiO4 Monolayer Membranes for Highly Selective H2S Detection from Hazardous Gas Mixtures

“…First-principles simulations were applied to explore molecular-level electronic properties of nanomaterials. , The adsorption and sensing behavior of SF 6 catabolites on Ni-doped C 3 N monolayers was analyzed using first principles; it revealed that N-vacancy was the preferred site for anchoring Ni atoms with higher binding energy . The gas-sensing mechanism of LaCoO 3 -modified ZnO was investigated by first-principles calculations; the improved performance was mainly related to the increasing O content and stronger oxidation activities of LCO .…”