The effect of surface curvature of aluminum nitride nanotubes on the adsorption of NH3

A density functional theory study on the potential application of Ni and Co doped ZnO nanosheets as a carrier for ciclopirox anticancer drug

The Ni and Co doping effect on the ciclopirox (CPX) drug delivery performance of a ZnO ‎nanosheet (ZnO-NS) was investigated theoretically. Doping Ni and Co metals into the ZnO-NS ‎increased the adsorption energy of CPX from -7.9 to -27.4 and -31.7 kcal/mol, respectively. ‎The CPX adsorption reduced the ZnO-NS gap (Eg) from 3.81 to 3.46 eV, while the CPX ‎adsorption reduced the Eg of the Ni- and Co-doped ZnO-NS from 2.74 and 2.68 eV to 1.87 and ‎‎1.71 eV, respectively. The CPX adsorption performance increased after doping process. A drug ‎release mechanism was introduced in cancerous tissues based on the PH.‎.

Adsorption of O2 molecule on the transition metals (TM(II) = Sc2+, Ti2+, V2+, Cr2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+) porphyrins induced carbon nanocone (TM(II)PCNC)

In this work, the adsorption of the O₂ molecule on the transition metals (TM^(II) = Sc²⁺, Ti²⁺, V²⁺, Cr²⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺) porphyrins induced carbon nanocone (TM^(II)-PCNC) were investigated using density functional theory (DFT) in terms of stabilities, energetic, structural, and electronic properties. It has been found that the O₂ molecule is adsorbed on the TM^(II)-PCNC with adsorption energies in the range of 0.29 to -98.32 kcal/mol. The interaction between the O₂ gas and the Sc-PCNC molecule from the outer site is the strongest. The interaction of the O₂ gas over the Ni-PCNC molecule from both outer and inner sites is the weakest. It can be concluded that the suitable interaction energy (E_g) for sensing ability attributed to the Zn-PCNC because an effective and physical interaction between Zn-PCNC and the O₂ gas leads to short recovery time. DFT calculations also clarified that the high %ΔE_g of Zn-PCNC and hence the high sensitivity to the O₂ gas confirm that the Zn-PCNC molecule is a promising candidate for having a good sensing ability to the O₂ gas.

Different metal-decorated aluminum phosphide nanotubes as hydrazine sensors for biomedical applications

B3LYP, B97D, and M06-2X density functionals are utilized for probing the effect of decorating X (X = Co, Ti, Sc, or Ca) metals on the sensing performance of an aluminum phosphide nanotube (AlPNT) in detecting the hydrazine (HZ) gas. We predict that the interaction of pristine AlPNT with HZ is physisorption, and our calculated sensing response (SR) of AlPNT is approximately 2.7. The adsorption energy of HZ changes from - 4.6 to - 21.0, - 21.9, - 22.4, and - 23.8 kcal/mol by decorating the Co, Ti, Sc, and Ca metals into the AlPNT surface, respectively. Also, Co, Ti, Sc, and Ca rise the SR to 22.5, 36.8, 50.4, and 89.0, respectively, indicating that by increasing the atomic radius of metals, the sensitivity is more increased. So, we concluded that Ca much more increases the sensitivity of AlPNT toward HZ. Our calculations demonstrate that the electrostatic interaction has the main contribution in the formation of HZ/X decorated AlPNT (X@AlPNT) complexes. The expected recovery time is 22.0 s for the HZ desorption from the Ca@AlPNT at 298 K. Finally, we found that all of the X@AlPNTs have superior sensing performance toward HZ compared to the X@carbon nanotubes.

A molecular modeling on the boron trichloride gas detection by S- and Cr-doped graphyne

Here, we scrutinize the adsorption of boron trichloride (BCl₃) on pure, S-doped, and Cr-doped graphyne by means of density functional theory (DFT) calculations. BCl₃ interacts weakly with pure graphyne, so it cannot be employed as a sensor. Despite the strengthening of interaction through S-doping, we cannot still employ the S-doped sheet as a sensor. Nevertheless, there is a considerable increase in the sensitivity and reactivity of the sheet through substituting the transition metal Cr for the C. There is a reduction in the HOMO-LUMO gap of Cr-doped graphyne from 2.18 to 1.38 eV when BCl₃ is adsorbed, thereby increasing the electrical conductivity to a great extent. Hence, it is possible to convert the considerable change in conductivity into an electronic signal, which demonstrates the encouraging nature of Cr-doped graphyne as a sensor to detect BCl₃. Additionally, the adsorption process reduces the work function of graphyne to a great extent, which demonstrates that we can also employ it as a work function-type sensor for detecting BCl₃.

Computational screening of carbon monoxide (CO) adsorption over neutral and charged Al7 clusters

A density functional theory study on the structures and chemical bonding of charged (Al7 + and Al7 -) and neutral Al7 clusters is presented. A distorted octahedral structure with an aluminum atom decorating one of the aluminum faces of the octahedron is predicted for these clusters. The AdNDP analysis reveals double (σ- and π-) aromatic and antiaromatic characteristics of Al7 + and Al7 - clusters, respectively. The UV-Vis Spectra of these clusters are also investigated using TD-DFT method. The molecular adsorption of carbon monoxide on the mentioned clusters is also explored. It is found that, the binding of CO through its carbon atom on considered clusters is a physical adsorption and Al7 - cluster shows the most tendency for the CO adsorption. The NBO analysis and density of states spectra confirm the weak interaction between carbon atom of CO and the aluminum atom of these clusters.

Experimental and theoretical calculation investigation of 2,4-dichlorophenoxyacetic acid adsorption onto core–shell carbon microspheres@layered double hydroxide composites

Layered double hydroxides (LDHs) usually aggregate irregularly and hardly redisperse in water. Moreover, the affinity of LDHs is poor for organic compounds. In this study, three different core–shell composites, i.e. CMS@MgAl–LDH, CMS@NiAl–LDH, and CMS@ZnAl–LDH, were synthesized by direct fabrication of LDH nanoplatelets onto carbon microspheres (CMS) for the removal of the adsorbed 2,4-dichlorophenoxyacetic acid (2,4-D). The CMS@LDH composites show good water-dispersity due to the 3D hierarchical sphere structure and high affinity for 2,4-D due to the organic carbon cores that possess abundant hydrophobic compounds. It was found that the adsorption process was rapid, and the time required to reach the sorption equilibrium was within 100 min. The theoretical DFT calculation analysis suggested that the adsorption of 2,4-D on the CMS@LDH composites was dominated by π–π interactions, ion-exchange, and hydrogen bonding. The core–shell CMS@LDH composites can serve as a promising adsorbent that offers a rapid and effective adsorption capacity for the removal of 2,4-D in an aqueous solution.

The core–shell CMS@LDH composites were successfully synthesized and exhibited an excellent adsorption performance for 2,4-D.

Electronic sensor for sulfide dioxide based on AlN nanotubes: a computational study

Single-walled aluminum nitride nanotubes (AlNNTs) are introduced as an electronic sensor for detection of sulfur dioxide (SO₂) molecules based on density functional theory calculations. The proposed sensor benefits from several advantages including high sensitivity: HOMO-LUMO energy gap of the AlNNT is appreciably sensitive toward the presence of SO₂ so that it decreases from 4.11 eV in the pristine tube to 1.01 eV in the SO₂-adsorbed form, pristine application: this nanotube can detect the SO₂ molecule in its pristine type without manipulating its structure through doping, chemical functionalization, making defect, etc., short recovery time: the adsorption energy of SO₂ molecule is not so large to hinder the recovery of AlNNTs and therefore the sensor will possess short recovery times, and good selectivity: the tube can selectively detect the SO₂ molecule in the presence of several molecules such as H₂O, CO, NH₃, HCOH, CO₂, N₂, and H₂.

Cation-π interaction of alkali metal ions with C24 fullerene: a DFT study

Using first principle calculations, we investigated cation-π interactions between alkali cations (Li(+), Na(+), and K(+)) and pristine C(24) or doped fullerenes of BC(23), and NC(23). The most suitable adsorption site is found to be atop the center of a six-membered ring of the exterior surface of C(24) molecule. Interaction energies of these cations decreased in the order: Li(+) > Na(+) > K(+), with values of -31.82, -22.36, and -15.68 kcal mol(-1), respectively. It was shown that the interaction energies are increased and decreased by impurity doping of B and N atoms in adjacent wall of adsorption site, depending on electron donating or receptivity of the doping atoms.

A comparative study on the B12N12, Al12N12, B12P12 and Al12P12 fullerene-like cages

The stability, geometry and electronic structure of the title nanoclusters were compared by using density functional theory (DFT) calculations. Their electrical property analysis showed that the relative magnitude of the HOMO-LUMO gaps (eV) that are average values from the calculated results with five different DFT functionals is as follows: B12N12(7:02)>>Al12N12(4.09)>B12P12(3.80)>Al12P12(3.39). Computing the standard enthalpy and the Gibbs free energy of formation, it was found that the B(12)N(12) structure is thermodynamically stable at 298 K and 1 atmosphere of pressure, while the Al(12)N(12) structure may be stable at low temperatures. Due to positive values of change of enthalpy and entropy of formation for both the B(12)P(12) and Al(12)P(12) clusters, it seems that their formation from the consisting atoms is not spontaneous at any temperature.