Modulating the Electronic Structure and Global Reactivity of Nitrogen/Boron Co-Doped Graphene Oxide: A Density Functional Theory Study for Enhanced Gas Sensing Applications

Density Functional Theory (DFT) calculations were applied at the B3LYP/6-311G+(d,p) level to examine how nitrogen (N) and boron (B) and combined nitrogen/boron doping (N/B) affected the electronic properties and chemical behavior of graphene oxide (GrO). The work aimed to measure how global reactivity descriptors, including ionization potential, chemical hardness, and electrophilicity, changed when dopants entered the system while evaluating their prediction accuracy for gas sensing performance against NH3 and H2O and CO2. The results show that undoped GrO exhibits a HOMO/LUMO gap value of 2.9059 eV while the introduction of dopants increases reactivity through gap reduction because N-doping decreased the gap to 1.3622 eV, B-doping reduced it to 1.3388 eV, and co-doping (GrO-NB) led to a gap of 1.9897 eV. The TDM analysis and the gas interaction energy gap results show that GrO-NB-H2O exhibits the strongest interaction which results in chemical reactivity through its lowest ΔE of 1.9565 eV, establishing itself as a highly sensitive water vapor sensor when compared with NH3 and CO2. With adsorption energies of −0.1986, −0.1742, and −0.0735 eV for NH3, H2O, and CO2, respectively, the N/B co-doped graphene oxide demonstrated favorable and reversible physisorption, underscoring its potential for gas sensing applications. The results offer an essential understanding of how N/B co-doping influences the electronic and adsorption characteristics of graphene oxide, thereby supporting its potential use in graphene-based sensing technologies.