Straightforward Synthesis of Borophene Nanolayers for Enhanced NO₂ Detection in Humid Environments

This study investigates the synthesis and gas sensing performance of borophene nanolayers produced through the sonochemical exfoliation method. The advantages of this method, including cost-effectiveness, simplicity and potential for scalability, make it a viable option for practical applications. High-resolution transmission electron microscopy (HRTEM) confirmed the successful exfoliation of boron into nanosheets with an average diameter of approximately 100 nm. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses revealed the β-rhombohedral crystal structure. Additionally, the existence of carbon and oxygen on the surface has been determined and investigated. At room temperature, the borophene nanolayers showed exceptional gas sensing capabilities for detecting nitrogen dioxide (NO2), especially in a humid environment. The sensitivity was significantly increased by about 50% when water molecules were present. These borophene nanolayers demonstrated unprecedented sensing performance for NO2, with detection (LOD) and quantification (LOQ) limits of 23 and 76 ppb, respectively.