Homonuclear B2/B3 doped carbon allotropes as a universal gas sensor: Possibility of CO oxidation and CO2 hydrogenation

Abstract

Carbon allotropes are known to be promising materials as chemical gas sensors. Proper modification in the electronic structure is required using suitable heteroatom doping to acquire better sensing property. We present the homonuclear B2 (BB) and B3 (BBB) doped carbon allotropes for the detection of toxic gases such as NO2, CO2, NH3, H2S and CO using the density functional theory. The sensitivity and selectivity of pure and boron doped C60 surfaces towards toxic gas molecules are estimated. With a new perception, the gas sensitivity has been correlated with π electron occupancy of the host materials. The adsorption behaviour of toxic gases on the host surface during the presence of H2O, O2 and O molecule/atom is estimated. The concept of homonuclear B sites is extended to 585 divacancy graphene and 585 divacancy carbon nanotube (CNT) system and verified that the phenomena are general for sp2 hybridized carbon allotrope. We also tested the CO oxidation and CO2 hydrogenation on B2 and B3 doped: C60 cage, 585 DV graphene and 585 DV CNT. The CO oxidation occurs via Langmuir–Hinshelwood (LH) mechanism. Overall we have found that the presence of homonuclear bond can change the inert carbon allotropes into highly active sensor material.