Ni-doped boron nitride nanotubes as promising gas sensing material for dissolved gases in transformer oil

Abstract

This paper reports that the transition metals (TM), including Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn, are substituted in a perfect zigzag (8, 0) boron nitride nanotubes (BNNTs) at B-site and N-site to improve the adsorption performance of intrinsic BNNTs towards oil-dissolved gases (H 2 , CH 4 , and C 2 H 2 ), particularly C 2 H 2 . In this regard, the quantum chemical calculations are performed based on the density functional theory (DFT). The results show that the C 2 H 2 gas adsorption characteristic of BNNTs is selectively enhanced due to the intervention of the TM atom. The Co B , Ni B, Cu B, Zn B, and Zn N are preliminarily selected as potential gas sensors for C 2 H 2 gas based on their suitable range of adsorption energy. The sensitivity, selectivity, and recovery time of the above five structures are compared. It is found that Ni B is a superior sensing material with exceptionally high sensitivity and selectivity. Moreover, the Ni B presented preferable desorption properties for C 2 H 2 gas at room temperature, making it promising for a chemical resistance-type gas sensing device. The analysis of charge transfer and density of states illustrates that the Ni B donates electrons to C 2 H 2 , proving its superiority over the adsorption properties for C 2 H 2 gas over H 2 and CH 4 . The suitable recovery time (2.3 s), extremely high gas response value (494383%), and stable chemisorption demonstrate that the Ni-doped BNNTs at B-site can be a superior chemical gas sensor for C 2 H 2 gas at room temperature.