Synthesis of hierarchical nanosheet-assembled V2O5 microflowers with high sensing properties towards amines

Abstract

Hierarchical three-dimensional nanosheet-assembled vanadium pentoxide (V₂O₅) microflowers are successfully synthesized by a hydrothermal method, followed by a high-temperature sintering treatment. Several advanced techniques are used to characterize the morphology and composition of the resulting nanostructures, such as TEM, HRTEM, SEM, XRD, and BET. The HRTEM image shows that the microflowers are assembled from the nanosheets with highly exposed {010} facets, as confirmed by selected area electron diffraction (SAED). According to N₂ sorption isothermal studies, the as-prepared V₂O₅ microflowers show high specific surface area of 61.5 m² g⁻¹. The formation of the microflowers with assistance of NaHCO₃, which may play a critical role in the self-assembly process, may be attributed to a “reproduction mechanism”. The gas sensing performances of both the V₂O₅ microflowers and the V₂O₅ nanosheets were evaluated towards several volatile organic compounds (VOCs), such as 1-butylamine, ethanol, acetone, and formaldehyde. The results show that the flower-like structure exhibits a superior sensing response and selectivity towards amines compared to that of the sheet-like structure at an optimum working temperature of ∼300 °C. The high selectivity towards 1-butylamine can be ascribed to the selective oxidation mechanism. This work will help explore vanadium oxides as gas sensors toward volatile organic compounds with high performance.