Chemical Sensing Properties of BaF2-Modified hBN Flakes towards Detection of Volatile Organic Compounds

Abstract

The application of BaF2-modified hBN flakes as rapid response and recovery as well as sensitive chemoresistive sensing device materials for detection of acetone and/or ethanol is presented in this study. Modification of the hBN flakes was achieved by using the modified polymer derived ceramics (PDCs) process through the use of 0–10 wt% BaF2 and 5 wt% Li3N. Upon exposure to individual acetone and ethanol vapours, room temperature sensing studies revealed high LoD values (−144–460 ppmacetone and −134–543 ppmethanol) with extremely compromised sensitivities of −0.042–0.72 × 10−2 ppm−1acetone and −0.045–0.19 × 10−2 ppm−1ethanol for the structurally improved 5–10 wt% BaF2-modified hBN flakes. Moreover, enhanced sensing for 0–2.5 wt% BaF2-modified hBN flakes, as shown by the low LoDs (−43–86 ppmacetone and −30–62 ppmethanol) and the high sensitivities (−1.8–2.1 × 10−2 ppm−1acetone and −1.5–1.6 × 10−2 ppm−1ethanol), was attributed to the presence of defects subsequently providing an abundance of adsorption sites. Overall, the study demonstrated the importance of structural properties of hBN flakes on their surface chemistry towards room temperature selective and sensitive detection of VOCs.