Band structure of graphene modulated by Ti or N dopants and applications in gas sensoring

• DFT method was used to investigate the adsorption of NO2 molecules onto Ti-, and N-doped graphene sheets.
• Ti-doped graphene could be used as a NO2 sensor without considering the effects of the NO and O2.
• The doped Ti atoms could modulate the band gap of the graphenes and the gas adsorption could also affect the band gap of graphenes.
• The study might be useful for explaining the details interactions between NO2 molecule and graphene based materials, which was helpful for designing the effective graphene-based sensors for environmental remediation.

The exploration of novel sensors for NO2 detection is particularly important in material and environmental sciences. In this work, the HOMO–LUMO gap of graphene, Ti- or N-doped graphene is investigated by DFT methods. The adsorption of NO2, NO, and O2 on Ti- or N-doped graphene of different sizes is also explored. Results reveal that the interactions between gases (NO2, NO, and O2) and Ti- or N-doped graphenes is not affected by the size of graphene. The doped Ti greatly improves the interactions between gases and graphene whereas the doped N has no effect on those interactions. The HOMO– LUMO gap of Ti-doped graphene can be modulated by adsorption of the gases. The cross effect of the NO and O2 is also investigated, and it is demonstrated that Ti-doped graphene has specific interactions with NO2. Thus, Ti-doped graphene can be a candidate for NO2 sensor materials. Furthermore, doping the graphene with Ti or N improves the sensitivity of the sheets toward NO2, which can be trapped and detected by the intrinsic graphene. Efficient sensors are rationally designed to diversify their applications in environmental science and engineering.

Doped density regulates the band gap of the graphene sheets which could greatly affect the adsorption process of the gas molecules.Figure optionsDownload high-quality image (210 K)Download as PowerPoint slide