Synthesis and evaluation of the gas sensing properties of 2D h-BNNSs as a semiconductor based gas sensor on H2S and CO gases at various temperatures

Abstract

Two-dimensional (2D) hexagonal boron nitride nanosheets (h-BNNSs) were synthesized using wet chemical reaction method through chemical vapor deposition (CVD) catalyst-free approach. The crystallinity of the nanosheets with the stacking of the B and N honeycomb lattice was validated by the XRD, while the TEM disclosed the specimen orientations and chemical compositions of phases with the number of layers of a planar honeycomb BN sheet. The FTIR, RM and the UV-vis expressed the formation of the in-plane, out-of-plane h-BN vibrations and, the nature of the surface with the thickness together with its optical properties. BET examined the surface properties of the h-BNNSs. The gas sensing properties of the 2D h-BNNSs were also investigated on hydrogen sulfide (H2S) and carbon monoxide (CO). The fabricated sensor based on 800 - $\boldsymbol{900}^{\circ}\mathrm{C}$ h-BNNSs showed good sensitivity towards ppm of H2S at $\boldsymbol{250}^{\circ}\mathrm{C}$. The excellent gas sensing properties could be attributed to high surface area, small crystallite size, defects of h-BNNSs. Overall, the h-BNNSs were found to be more sensitive to H2S than CO.