DFT-Based Theoretical Study of Structural, Stability, Electronic, and Thermodynamic Properties of Nitrogen Doped Graphene-TiO₂ Heterostructure

This study investigates the structural, stability, electronic, and thermodynamic properties of nitrogen-doped graphene (NGR) integrated with titanium dioxide (TiO₂).The NGR/TiO₂ heterostructure consists of 98 atoms (47 carbon, 32 oxygen, and 16 titanium) with three nitrogen doping sites.Comprehensive analysis reveals a minimum separation of 3 Å between TiO₂ and NGR, with a formation energy of -5.47 eV, indicating weak van der Waals interactions rather than covalent bonding.The optimized structure exhibits exceptional stability, as validated by phonon dispersion spectra that are devoid of imaginary frequencies.Electronic band structure calculations reveal the absence of an energy gap, which enhances electrical conductivity and photocatalytic performance, attributed to N-induced states near the Fermi level.Nitrogen dopants tend to acquire negative charges, which is consistent with their elevated electronegativity in comparison to carbon, thereby facilitating the attraction of electron density.These findings suggest that modifying NGR/TiO₂ with dopants can improve interfacial interactions, paving the way for advanced applications in energy storage and photocatalysis.