Novel synthesis of porous BN/β-SiC/SnO₂/In₂O₃ quaternary nanocomposites and its gas sensing properties under different working temperatures

A novel quaternary nanocomposite composed of porous boron nitride, β-SiC fibers, SnO₂, and In₂O₃ was successfully synthesized and their interconnection led to effective and highly stable gas sensing. The formation of the newly modeled quaternary nanocomposite enabled the formation of an effective electron transfer pathway and provided a large contact area between the detecting gas and gas sensor material. The physical and chemical properties of the nanocomposites were analyzed using analytical techniques, such as XRD, SEM, TEM-HRTEM, BET, XPS, PL, and Raman techniques. First-principles calculations were performed to evaluate the proportion of states occupied by the system at each energy level. The gas-sensing capabilities of the quaternary nanocomposites were evaluated using CO₂ and O₂ gas purging at various temperatures. The gas-sensing capabilities of the quaternary nanocomposites were evaluated using CO₂ and O₂ gas purging at different temperatures. The gas-sensing properties of the β-SiC fiber and the previously studied β-SiC/In₂O₃/SnO₂ were improved by the exceptional electronic conductivity and chemical activity of the pBN/β-SiC/SnO₂/In₂O₃ quaternary nanocomposites. At room temperature, the pBN-105 NCs exhibited the high resistance to O₂ gas and a weak response to CO₂ gas. However, the sensor exhibited strong sensitivity to both CO₂ and O₂ gases at high temperatures. In each gas-sensing test, the quaternary nanocomposites exhibited strong resistance and low current density. The effective charge transfer and separation properties, as well as the electron density of the sensor layer of the quaternary nanocomposites, allowed for better sensing under a range of high-temperature variations, while the addition of MOs and porous boron nitride increased the usefulness of the β-SiC fiber.

Graphical abstract of the fabrication of the nanostructured pBN/β−SiC fiber/SnO₂/In₂O₃ gas sensor and the CO2/O2 gas sensing mechanism