Investigation into the NO2 gas sensing behaviour of defect-induced heteroatom (N, B)-doped reduced graphene oxide-modified mesoporous MgFe2O4

Abstract

One of the principal gaseous pollutants that endangers the environment and human health is nitrogen dioxide (NO₂) gas, mainly emitted through combustion sources. Even at quantities of tens of ppb, prolonged exposure to NO₂ can cause asthma symptoms or reduced respiratory function. Therefore, NO₂ sensors with high sensitivity, accuracy, and low detection limits are highly desirable for protecting the environment and human health. Focusing on this issue, a low-cost and easy synthetic procedure was adopted for heteroatom (N, B)-doped reduced graphene oxide and a mesoporous MgFe₂O₄-based nanocomposite. Higher electrical conductivity of reduced graphene oxide and the defect generation due to heteroatom doping synergises with the sensing capabilities of mesoporous MgFe₂O₄. The designed sensor can sense up to a lower concentration of 10 ppm at room temperature. Along with the developed sensor's higher sensing capability, its good recyclability makes it favorable for detecting toxic gaseous analytes. The combined effect of higher surface area (N₂ adsorption–desorption isotherm) and defect generation due to heteroatom doping and mesoporosity of MgFe₂O₄ spinel was the reason behind the higher response.