A highly specific heterostructure composed of N-doped TiO2 anatase nanoparticles and double layer Au for detection of thiophene molecule: A DFT study

The adsorption of thiophene molecule on the pristine, N-doped and Cu/N codoped TiO2-supported Au overlayers has been studied using density functional theory calculations, taking into consideration the effects of van der Waals interaction. Thiophene molecule can be adsorbed on both the Au and five-fold coordinated titanium sites of TiO2 supported Au overlayers. Various adsorption configurations of thiophene over the considered TiO2 supported Au overlayers are discussed. It is found that with Cu/N codoped nanoparticle as an adsorbent, the adsorption configuration is more stable and consequently the adsorption process is more energetically favorable. The adsorption of thiophene molecule on the N-doped TiO2 supported Au overlayers is more energetically favorable than the adsorption on the undoped ones. On the Cu/N codoped nanoparticle, the adsorption process is more strongly favored. Thus, Cu/N-codoped system can interact with thiophene molecule more efficiently. The considerable overlaps between the PDOSs of the sulfur and titanium atoms indicate chemical bond forms between these two atoms. These chemical bonds confirm chemisorption of thiophene on the TiO2 supported Au overlayers. After the adsorption process, the HOMOs are mainly distributed over the adsorbed thiophene molecule. The charge analysis based on Mulliken charges reveals that charge is transferred from the thiophene molecule to the TiO2 supported Au. This study not only suggests a theoretical basis for adsorption behaviors of thiophene on the TiO2-supported Au overlayers, but also provides an efficient strategy to design and improve highly efficient sensor devices for thiophene detection

Molecular adsorption study of nicotine on the nitrogen doped TiO₂ anatase nanoparticles: Insights from van der Waals corrected DFT computations

1182-1191The interaction of nicotine with undoped and nitrogen-doped TiO2 anatase nanoparticles is investigated by density functional theory studies. The results indicate that the interaction between nicotine and N-doped TiO2 nanoparticles is stronger than that between nicotine and pristine TiO2 nanoparticles, which suggests nitrogen doping helps to strengthen the interaction of nicotine with TiO2 nanoparticles. In other words, the doping of nitrogen atom promotes the interaction of nicotine with TiO2 nanoparticles. It is found that the nitrogen atom of nicotine molecule tends to be strongly adsorbed on the five-fold coordinated titanium site of N-doped anatase nanoparticles. By including van der Waals interactions between nicotine molecule and TiO2, it is found that the adsorption on the N-doped TiO2 is energetically more favorable than that on the pristine one. The projected density of states analysis indicates the formation of chemical bond between nitrogen atom of nicotine and titanium atom of nanoparticle. These results offer a theoretical basis and general understanding of the interaction of TiO2 nanoparticles with nicotine, suggesting potential applications of N-doped TiO2 nanoparticles in designing of novel sensors and removers for nicotine detection

Adsorption of H2S molecule on TiO2/Au nanocomposites: A density functional theory study

The adsorption of hydrogen sulfide molecule on undoped and N-doped TiO2/Au nanocomposites was investigated by density functional theory (DFT) calculations. The results showed that the adsorption energies of H2S on the nanocomposites follow the order of 2N doped (Ti site)>N-doped (Ti site)>Undoped (Ti site). The structural properties including bond lengths, angles and adsorption energies and electronic properties in view of the projected density of states (PDOSs) and molecular orbitals (MOs) were analyzed in detail. The results indicated that the interaction between H2S molecule and N-doped TiO2/Au nanocomposite is stronger than that between H2S and undoped nanocomposite, suggesting that N-doping helps to strengthen the interaction of H2S with TiO2/Au nanocomposite. Mulliken population analysis was conducted to analyze the charge transfer between the nanocomposite and H2S molecule. Although H2S molecule has no significant interaction with undoped nanocomposite, it tends to be strongly adsorbed on the N-doped nanocomposite. The results also suggest that the two doped nitrogen atoms in TiO2 greatly strengthen the adsorption process, being a helpful procedure to help in the design and development of improved sensor devices for H2S detection

A highly specific heterostructure composed of N-doped TiO₂ anatase nanoparticles and double layer Au for detection of thiophene molecule: A DFT study

34-43The adsorption of thiophene molecule on the pristine, N-doped and Cu/N codoped TiO2-supported Au overlayers has been studied using density functional theory calculations, taking into consideration the effects of van der Waals interaction. Thiophene molecule can be adsorbed on both the Au and five-fold coordinated titanium sites of TiO2 supported Au overlayers. Various adsorption configurations of thiophene over the considered TiO2 supported Au overlayers are discussed. It is found that with Cu/N codoped nanoparticle as an adsorbent, the adsorption configuration is more stable and consequently the adsorption process is more energetically favorable. The adsorption of thiophene molecule on the N-doped TiO2 supported Au overlayers is more energetically favorable than the adsorption on the undoped ones. On the Cu/N codoped nanoparticle, the adsorption process is more strongly favored. Thus, Cu/N-codoped system can interact with thiophene molecule more efficiently. The considerable overlaps between the PDOSs of the sulfur and titanium atoms indicate chemical bond forms between these two atoms. These chemical bonds confirm chemisorption of thiophene on the TiO2 supported Au overlayers. After the adsorption process, the HOMOs are mainly distributed over the adsorbed thiophene molecule. The charge analysis based on Mulliken charges reveals that charge is transferred from the thiophene molecule to the TiO2 supported Au. This study not only suggests a theoretical basis for adsorption behaviors of thiophene on the TiO2-supported Au overlayers, but also provides an efficient strategy to design and improve highly efficient sensor devices for thiophene detection

Van der Waals corrected DFT study on the adsorption behaviors of TiO2 anatase nanoparticles as potential molecule sensor for thiophene detection

Density functional theory investigations were conducted in order to study the effects of the adsorption of thiophene on the structural and electronic properties of TiO2 anatase nanoparticles. The ability of pristine and N-doped TiO2 anatase nanoparticles to recognize toxic thiophene was surveyed in detail. It was found that thiophene molecule is chemisorbed on the N-doped anatase nanoparticles in S site geometries with large adsorption energy and small distance. By including van der Waals (vdW) interactions between thiophene molecule and TiO2, we found that the adsorption on the N-doped TiO2 is energetically more favorable than the adsorption on the pristine one, suggesting that the nitrogen doping can energetically facilitate the thiophene adsorption on the N-doped nanoparticle. The order of adsorption energy is Parallel(S site)>Perpendicular(S site)>Perpendicular (H site). The interaction between thiophene and N-doped TiO2 can induce substantial variations in the HOMO/LUMO molecular orbitals of the nanoparticle, changing its electrical conductivity, which is helpful for designing the novel sensor and remover devices. Charge analysis based on Mulliken charges reveals that charge is transferred from thiophene molecule to TiO2 nanoparticle

A theoretical investigation of the interaction of Immucillin-A with N-doped TiO2 anatase nanoparticles: Applications to nanobiosensors and nanocarriers

Objective(s): Adsorption of IMMUCILLIN-A (BCX4430) molecule on the pristine and N-doped TiO2 anatase nanoparticles were studied using the density functional theory (DFT) calculations. The adsorption energy analysis indicated that TiO2+IMMUCILLIN-A complexes including OC-substituted TiO2 have higher adsorption energy than the complexes with OT substituted TiO2, thus providing more stable configurations. Methods: The structural properties including bond lengths, adsorption energies and bond angles were analysed. The electronic structure of the adsorption system were investigated in view of the density of states, molecular orbitals and Mulliken charge analysis.Results: The results show that, the interaction of IMMUCILLIN-A drug with N-doped TiO2 nanoparticles is more energetically favorable than the interaction with the pristine ones, suggesting that the N-doped nanoparticles can react with IMMUCILLIN-A drug more efficiently. The Mulliken charge analysis also suggests a charge transfer from IMMUCILLIN-A molecule to the TiO2 nanoparticle.Conclusions: Based on obtained results, it can be concluded that the N-doped TiO2 nanoparticle could be utilized as an efficient candidate for application as highly sensitive nanobiosensors and efficient nanocarriers for IMMUCILLIN-A drugs

A First-Principles Study of the Interaction of Aspirin with Nitrogen-Doped TiO2 Anatase Nanoparticles

Objective(s): First-principles calculations have been carried out to investigate the interaction of aspirin molecule with nitrogen-doped TiO2 anatase nanoparticles using the density functional theory method in order to fully exploit the biosensing capabilities of TiO2 particles. Methods: For this purpose, we have mainly studied the adsorption of the aspirin molecule on the fivefold coordinated titanium atom site of the TiO2 nanoparticles because of the more reactivity of this site in comparison with the other sits. The complex systems consisting of the aspirin molecule positioned toward the undoped and nitrogen-doped nanoparticles have been relaxed geometrically. Results: The obtained results include structural parameters such as bond lengths and energetic of the systems. The electronic structure and its variations resulting from the adsorption process, including the density of states, molecular orbitals and the Mulliken charge transfer analysis have been discussed. We found that the adsorption of aspirin molecule on the nitrogen-doped TiO2 nanoparticles is energetically more favorable than the adsorption on the undoped ones. Conclusions: These results thus provide a theoretical basis and overall understanding on the interaction of TiO2 nanoparticles with aspirin molecule for applications in modeling of efficient nanomedicine carriers, biosensors and drug delivery purposes