DFT study of CO adsorption on nitrogen/boron doped-graphene for sensor applications

Density functional theory study of doped coronene and circumcoronene as anode materials in lithium-ion batteries

Density functional theory calculations are carried out to investigate the adsorption properties of Li+ and Li on twenty-four adsorbents obtained by replacement of C atoms of coronene (C24H12) and circumcoronene (C54H18) by Si/N/BN/AlN units. The molecular electrostatic potential (MESP) analysis show that such replacements lead to an increase of the electron-rich environments in the molecules. Li+ is relatively strongly adsorbed on all adsorbents. The adsorption energy of Li+ (Eads-1) on all adsorbents is in the range of - 42.47 (B12H12N12) to - 66.26 kcal/mol (m-C22H12BN). Our results indicate a stronger interaction between Li+ and the nanoflakes as the deepest MESP minimum of the nanoflakes becomes more negative. A stronger interaction between Li+ and the nanoflakes pushes more electron density toward Li+. Li is weakly adsorbed on all adsorbents when compared to Li+. The adsorption energy of Li (Eads-2) on all adsorbents is in the range of - 3.07 (B27H18N27) to - 47.79 kcal/mol (C53H18Si). Assuming the nanoflakes to be an anode for the lithium-ion batteries, the cell voltage (Vcell) is predicted to be relatively high (> 1.54 V) for C24H12, C12H12Si12, B12H12N12, C27H18Si27, and B27H18N27. The Eads-1 data show only a small variation compared to Eads-2, and therefore, Eads-2 has a strong effect on the changes in Vcell.

Recent advances in density functional theory approach for optoelectronics properties of graphene

Graphene has received tremendous attention among diverse 2D materials because of its remarkable properties. Its emergence over the last two decades gave a new and distinct dynamic to the study of materials, with several research projects focusing on exploiting its intrinsic properties for optoelectronic devices. This review provides a comprehensive overview of several published articles based on density functional theory and recently introduced machine learning approaches applied to study the electronic and optical properties of graphene. A comprehensive catalogue of the bond lengths, band gaps, and formation energies of various doped graphene systems that determine thermodynamic stability was reported in the literature. In these studies, the peculiarity of the obtained results reported is consequent on the nature and type of the dopants, the choice of the XC functionals, the basis set, and the wrong input parameters. The different density functional theory models, as well as the strengths and uncertainties of the ML potentials employed in the machine learning approach to enhance the prediction models for graphene, were elucidated. Lastly, the thermal properties, modelling of graphene heterostructures, the superconducting behaviour of graphene, and optimization of the DFT models are grey areas that future studies should explore in enhancing its unique potential. Therefore, the identified future trends and knowledge gaps have a prospect in both academia and industry to design future and reliable optoelectronic devices.

The interaction between H and CH3 of adsorption on the diamond (100)-2 × 1 surface based on DFT Calculations

In this research, the interaction mechanism between H and CH₃ of chemisorption on diamond (100)-2 × 1 surface was studied through the density functional theory (DFT) method. The H or CH₃ adsorbates were assumed to be directly chemisorbed to the final position on the surface in thermodynamic studies. The adsorption energies of individual H and CH₃ chemisorbed on the diamond surface were calculated, respectively. Subsequently, the adsorption energies for another H or CH₃ in five different positions adjacent to the initial H or CH₃ were calculated and compared. We find the universal law of the most likely chemisorption position. The results revealed that when one carbon atom of the dimer chemisorbed one radical, the other carbon atom of the dimer generated a dangling bond and had more ability to chemisorb other radicals. Therefore, the growth rate is faster along the direction of the carbon dimer than in other directions during the growth of the diamond film. The dimer is exactly towards the [110] direction. As films thicken, diamond tends to grow along the [110] direction. Therefore, it could explain that the [110] texture appears easily in the experiment. And, the results can be used to analyze the detailed process relative to the growth of the diamond film.

A density functional theory study on the adsorption reaction mechanism of double CO2 on the surface of graphene defects

Much research has been done on reactions of a single CO₂ molecule with a graphene surface. In this paper, density functional theory calculations are used to investigate the adsorption and reaction of double CO₂ on the surface of single vacancy (SV) and divacancy (DV) defect graphene. The study found that due to the mutual repulsion between CO₂ and the size of the SV defect, it is difficult for two CO₂ molecular to be adsorbed directly above the SV defect at the same time. Regardless of SV or DV, the adsorption of the first CO₂ in the defect center will have a beneficial effect on the adsorption of the second CO₂. In addition, the transition state calculation of the CO₂ reaction on the DV plane was carried out, and the adsorption behavior was analyzed and studied. This in-depth study is helpful to the understanding of the reaction behavior of CO₂ on graphene, and further exploration in the direction of the effective application of graphene to the reaction and adsorption of CO₂. Our work explores the adsorption behavior of CO₂ on graphene surfaces, the physical and chemical adsorption of double CO₂ at the defect was studied and analyzed.

Theoretical Study of CO Adsorption Interactions with Cr-Doped Tungsten Oxide/Graphene Composites for Gas Sensor Application

The present study explores the CO adsorption properties with graphene, tungsten oxide/graphene composite, and Cr-doped tungsten oxide/graphene composite using density functional theory (DFT) calculations. The results of the study reveal the Cr-doped tungsten oxide/graphene composites, g-CrW n-1O3n (n = 2 to 4), to have a lowered highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gap, high surface reactivity, and a strong cluster-graphene binding energy, hence exhibiting a strong adsorption interaction with CO. The CO adsorption interaction shows physisorption properties by having a greater tendency for Mulliken and natural bond orbital (NBO) charge transfer supported by a strong physisorption interaction toward the g-CrW n-1O3n (n = 2 to 4) composite with HOMO-LUMO energy gaps of -0.638, -0.486, and -0.327 eV, respectively. The calculated photoelectron spectroscopy (PES) and infrared spectra combined with the visualized electrostatic potential and contour line confirm the population density of the physisorption interaction. The calculated results show that the g-CrW n-1O3n composite achieves a greater sensing ability by possessing the highest sensitivity, adsorption, and desorption characteristics for n = 2 (g-CrWO6 composite). In conclusion, Cr-doped tungsten oxide/graphene has high sensitivity toward CO gas.

Reversible CO2 storage and efficient separation using Ca decorated porphyrin-like porous C24N24 fullerene: a DFT study

The search for novel materials for effective storage and separation of CO₂ molecules is a critical issue for eliminating or lowering this harmful greenhouse gas. In this paper, we investigate the potential application of a porphyrin-like porous fullerene (C₂₄N₂₄) as a promising material for CO₂ storage and separation using thorough density functional theory calculations. The results show that CO₂ is physisorbed on bare C₂₄N₂₄, implying that this material cannot be used for efficient CO₂ storage. Coating C₂₄N₂₄ with Ca atoms, on the other hand, can greatly improve the adsorption strength of CO₂ molecules due to polarization and charge-transfer effects. Furthermore, the average adsorption energy for each of the maximum 24 absorbed CO₂ molecules on the fully decorated Ca₆C₂₄N₂₄ fullerene is −0.40 eV, which fulfills the requirement needed for efficient CO₂ storage (−0.40 to −0.80 eV). The Ca coated C₂₄N₂₄ fullerene also have a strong potential for CO₂ separation from CO₂/H₂, CO₂/CH₄, and CO₂/N₂ mixtures.

Using dispersion-corrected DFT calculations, the potential application of a porphyrin-like porous fullerene (C₂₄N₂₄) as an efficient material for CO₂ storage and separation was investigated.

In-plane graphene/boron nitride heterostructures and their potential application as toxic gas sensors

After the successful synthesis of graphene/hexagonal boron nitride (h-BN) heterostructures, research works have been carried out for their plausible real-world device applications. Such 2D nanosheets gain great attention as they have shown promising gas sensing properties due to their high surface-to-volume ratio and unique electronic properties between graphene and h-BN. Herein, we report a first-principles density functional theory investigation of the structural and electronic properties of pristine graphene (PG), pristine BN, and their in-plane heterostructures employing B3LYP and dispersion-corrected van der Waals functional WB97XD with the 6-311G (d, p) basis set. We found that these predicted nanosheets show good structural stability with favorable cohesive energy and the bandgap gradually increases with the increase in the B–N concentration. We have also studied their adsorption properties toward toxic gas molecules (SO₂ and CO). Among these heterostructures, G2BN2 exhibits greater adsorption energy of about −0.237 eV and −0.335 eV when exposed to SO₂ and CO gas molecules, respectively. The electronic properties such as HOMO and LUMO energies, HOMO–LUMO energy gap, Fermi level, work function, and conductivity significantly changed after the adsorption of SO₂ gas on the nanosheets except for PG, whereas these parameters remain almost the same after the adsorption of the CO gas molecule. Mulliken and natural bond orbital (NBO) charge analysis reveals that charge transfer occurs from gas molecules to the nanosheets except when SO₂ is adsorbed onto PG. Although the adsorption energies for CO gas are slightly greater than those for SO₂ gas for these nanosheets, all other investigations such as electronic properties, charge transfer analysis, molecular electrostatic potential (MEP) map, and global indices predict that these nanosheets are good sensors for SO₂ gas than CO gas molecules.

DFT methods were used to study the surface geometry of in-plane 2D graphene/BN heterostructures and their effects on the adsorption properties.

Catalytic role of graphitic nitrogen atoms in the CO oxidation reaction over N-containing graphene: a first-principles mechanistic evaluation

The catalytic role of graphitic nitrogen atoms of a series of nitrogen-doped graphene surfaces is explored for low-temperature oxidation of CO using periodic DFT calculations.

Interaction investigation of single and multiple carbon monoxide molecules with Fe-, Ru-, and Os-doped single-walled carbon nanotubes by DFT study: applications to gas adsorption and detection nanomaterials

Due to the large surface area and unique electronic property, single-wall carbon nanotube (SWCNT) is being used for adsorption and detection nanomaterials, which can be used to reduce the CO pollution effect on the environment. In the present work, the adsorptions of single and multiple CO molecules on pristine and transition metal (TM = Fe-, Ru-, and Os)-doped SWCNT were investigated in terms of geometric, energetic, and electronic properties using density functional theory calculation. Calculated results display that the adsorption of CO molecule on the SWCNTs is energetically favorable. The TM-doped SWCNT are more highly interactive to CO adsorption than that of pristine SWCNT. An Os-doped SWCNT displays the strongest interaction with single and multiple CO molecules comparing with the Fe- and Ru-doped SWCNT. The TM doping on SWCNT can induce the charge transfer between CO molecule and the SWCNT. The energy gap and density of state are clearly changed when CO molecule interacts with TM-doped SWCNT, resulting in dramatic changes of their electronic properties. Therefore, TM-doped SWCNT are possibly used as potential CO storages/absorbents or sensor material for CO detection in the environment. Graphical abstract.