Diphenylamine-based hole-transporting materials for excessive-overall performance perovskite solar cells: Insights from DFT calculations.

Density functional theory calculations were employed to identify the ability of some diphenylamine-based hole-transporting materials (HTMs) for use in top-performance perovskite solar cells. The effects of donor/acceptor electron groups and the new π-bridge section in the three-part of structures were investigated thoroughly. The results indicated that adding electron-withdrawing functional groups such as CN in the phenylazo-indol moiety and substituting electron donor groups such as CH3 in the NH2 hydrogen atoms of the diphenylamine section can cause higher power conversion light-harvesting efficiency in new HTMs. Also, the replacement of thieno [3,2-b] benzothiophene as a part of the π bridge with the phenyl group according to the optical and electronic structure properties improves the efficiency of the new phenylazoindole derivatives.

Anthracite based activated carbon impregnated with HMTA as an effectiveness adsorbent could significantly uptake gasoline vapors.

In this study, we synthesized and employed the amine impregnated activated carbon as an efficacious adsorbent for uptaking gasoline vapor. For this regard, anthracite as activated carbon source and hexamethylenetetramine (HMTA) as amine were selected and utilized. Physiochemical characterization of made sorbents were evaluated and investigated using SEM, FESEM, BET, FTIR, XRD, zeta potential, and elemental analysis. The synthesized sorbents provided an excellent textural features as compared with the literature and other activated carbon based sorbents and impregnated with amine. Our findings also suggested that in addition to high surface area (up to 2150 m2 / g), the micro- meso pores created (Vmeso / V micro = 0.79 Cm 3 / g) surface chemistry may significantly affect the gasoline sorption capacity, which here the role of mesoporous is further highlighted. V meso for amine impregnated sample and free activated carbon was 0.89 and 0.31 Cm 3 / g, respectively. According to the results, the prepared sorbents have a potential capability in uptaking gasoline vapor and with line this, we report a high sorption capacity of 572.56 mg / g. After, four cycles used the sorbent had a high durability and about 99.11% of the initial uptake was maintained. Taking together the synthesized adsorbents as an activated carbon provided an excellent and unique features and enhanced gasoline uptake, therefore its applicability in uptaking gasoline vapor can be substantially considered.

Efficient delivery of anticancer 5-fluorouracil drug by alkaline earth metal functionalized porphyrin-like porous fullerenes: A DFT study.

Finding and developing effective targeted drug delivery systems has emerged as an attractive approach for treating a wide range of diseases. In the present study, the potential of alkaline earth metal functionalized porphyrin-like porous C24N24 fullerenes for delivering 5-fluorouracil (5FU) anticancer drug is assessed using density functional theory calculations. The goal is to evaluate how the addition of alkaline earth metals to C24N24 enhances the adsorption capabilities of this system towards 5FU drug. The adsorption energies and charge transfers are determined in order to evaluate the strength of the interaction between the 5FU and fullerene surfaces. According to the results, adding alkaline earth metals increases the drug's adsorption energy on the C24N24 fullerene. In all cases, the drug molecule interacts with the metal atom through its CO group. Furthermore, the adsorption strength of the 5FU increases with metal atom size (Ca > Mg > Be), which is connected to the polarizability of these atoms. The adsorption energies of 5FU are shown to be highly sensitive on solvent effects and the acidity of the environment. The adsorption strength of 5FU decreases within the solvent (water), allowing it to be released more easily. The moderate adsorption energies and short desorption times of 5FU imply that it is reversibly adsorbed on the functionalized fullerenes.

Exploring the potential use of Fe-decorated B40 borospherene as a prospective catalyst for oxidation of methane to methanol.

First-principles calculations based on density functional theory were utilized to evaluate whether an iron atom decorated B40 borospherene can be employed as a catalyst for converting methane (CH4) to methanol (CH3OH) in the presence of N2O or O2 molecule. Geometry optimizations indicated that N2O and O2 are both chemisorbed on the Fe atom of the catalyst, whereas CH4 is physisorbed. Using N2O as the oxidant, the oxidation of CH4 begins with N2O decomposition on the catalyst, which has an activation barrier of 0.50 eV. The CH4 molecule then combines with the activated O atom remained on the Fe to form the CH3OH molecule. However, the oxidation of CH4 with O2 requires an activation barrier as high as 1.91 eV, implying that this process is unlikely to occur under normal conditions. These novel results are anticipated to help in the design and modeling of noble-metal free catalysts for CH4 oxidation.

Hollow nano-CaCO3's VOC sensing properties: A DFT calculation and experimental assessments.

Air is the most critical and necessary for life, and air quality significantly impacts people's health. Both indoor and outdoor pollution frequently contain volatile organic compounds (VOCs). Such contaminants provide immediate or long-term health risks to the living system. The present study investigates sorption characteristics of VOCs on hollow nano calcite (CaCO3) particles with 250 nm and 40 nm pore sizes to remove from the air ambient using the quartz crystal microbalance (QCM) technique at room temperature both experimentally and theoretically. The results were supported by density functional theory (DFT), and adsorption-desorption characteristics were studied with Langmuir adsorption isotherms. The QCM measurements showed a stable signal without having hysteresis, and the response of polar VOCs on hollow nano-CaCO3 particles such as ethanol, propanol, and humidity with higher polarity was less compared to solvents such as chloroform and dichloromethane, which revealed that the surfaces of CaCO3 particles have mostly non-polar properties. CaCO3 surface and VOC molecule interactions overlap with the Langmuir model. With DFT calculations, VOC and water molecule adsorption changes the CaCO3 Egap. Our findings show that the ΔEgap values increase as chloroform > dichloromethane > propanol > ethanol > water. This order suggests that the sensing response of the hollow CaCO3 structure is linearly proportional to the adsorption energies of VOC and water. The linear adsorption characteristics, high sensing response, and short recovery time illustrated that the newly synthesized nano-CaCO3 could be implemented as a new VOC adsorbent material for health, environmental sustainability, and in vitro microbiome cultures.

Oxidation of methane and ethylene over Al incorporated N-doped graphene: A comparative mechanistic DFT study.

It is generally recognized that developing effective methods for selective oxidation of hydrocarbons to generate more useful chemicals is a major challenge for the chemical industry. In the present study, density functional theory calculations are conducted to examine the catalytic partial oxidation of methane (CH4) and ethylene (C2H4) by nitrous oxide (N2O) over Al-incorporated porphyrin-like N-doped graphene (AlN4-Gr). Adsorption energies for the most stable configurations of CH4, C2H4, and N2O molecules over the AlN4-Gr catalyst are determined to be -0.25, -0.64, and -0.40 eV, respectively. According to our findings, N2O can be efficiently split into N2 and Oads species with a negligible activation energy on the AlN4-Gr surface. Meanwhile, CH4 and C2H4 molecules compete for reaction with the activated oxygen atom (Oads) that stays on the surface. The energy barriers for partial methane oxidation through the CH4 + Oads → CH3° + HOads and CH3° + HOads → CH3OH reaction steps are 0.16 eV and 0.27 eV, respectively. Furthermore, the produced CH3OH may be overoxidized by Oads to give formaldehyde and water molecules by overcoming a relatively low activation barrier. The activation barriers for C2H4 epoxidation are small and comparable to those for CH4 oxidation, implying that AlN4-Gr is highly active for both reactions. The high energy barrier for the 1,2-hydrogen shift in the OCH2CH2 intermediate, on the other hand, makes the production of acetaldehyde impossible under normal conditions. According to the population analysis, the AlN4-Gr serves as a strong electron donor to aid in the charge transfer between the Al atom and the Oads moiety, which is necessary for the activation of CH4 and C2H4. The findings of the present study may pave the way for a better understanding of the catalytic oxidation the CH4 and C2H4, as well as for the development of highly efficient noble-metal free catalysts for these reactions.

Silicon-doped boron nitride graphyne-like sheet for catalytic N2O reduction: A DFT study.

In this work, spin-polarized density functional theory calculations are conducted to evaluate the possible applicability of a single Si atom doped boron nitride graphyne-like nansoheet (Si@BN-yne) for reduction of nitrous oxide (N2O). The calculations show that Si-doping in BN graphene is energetically favorable, and the resulting Si@BN-yne is both dynamically and thermodynamically stable. According to our findings, N2O spontaneously dissociates when it interacts with the Si@BN-yne from its O site without the need for an energy barrier, releasing 2.89 eV of energy. The adsorption energy of CO molecule on the Si@BN-yne is less negative than that of N2O, implying that N2O will predominately occupy the catalyst surface. The CO + Oad reaction is used to remove the remaining oxygen atom (Oad) from the Si@BN-yne surface. The calculations show that the reaction proceeds through a low energy barrier of 0.05 eV, which is much lower than the previously reported catalysts. This demonstrates the high catalytic activity of Si@BN-yne nanosheet. Furthermore, the adsorption of H2O and O2 species on the Si@BN-yne nanosheet is investigated. The results show that the presence of these species has no effect on the catalytic activity of the Si@BN-yne for N2O reduction. These results show that the proposed novel Si@BN-yne catalyst can be regarded as an efficient material in the development of promising active catalysts for N2O elimination from the environment.

Electrochemical reduction of NO catalyzed by boron-doped C60 fullerene: a first-principles study.

The electrochemical reduction of nitrogen monoxide (NO) is one of the most promising approaches for converting this harmful gas into useful chemicals. Using density functional theory calculations, the work examines the potential of a single B atom doped C60 fullerene (C59B) for catalytic reduction of NO molecules. The results demonstrate that the NO may be strongly activated over the B atom of C59B, and that the subsequent reduction process can result in the formation of NH3 and N2O molecules at low and high coverages, respectively. Based on the Gibbs free energy diagram, it is inferred that the C59B has excellent catalytic activity for NO reduction at ambient conditions with no potential-limiting. At normal temperature, the efficient interaction between the *NOH and NO species might lead to the spontaneous formation of the N2O molecule. Thus, the findings of this study provide new insights into NO electrochemical reduction on heteroatom doped fullerenes, as well as a unique strategy for fabricating low-cost NO reduction electrocatalysts with high efficiency.

Alkali metal decorated C60 fullerenes as promising materials for delivery of the 5-fluorouracil anticancer drug: a DFT approach.

The development of effective drug delivery vehicles is essential for the targeted administration and/or controlled release of drugs. Using first-principles calculations, the potential of alkali metal (AM = Li, Na, and K) decorated C60 fullerenes for delivery of 5-fluorouracil (5FU) is explored. The adsorption energies of the 5FU on a single AM atom decorated C60 are -19.33, -16.58, and -14.07 kcal mol-1 for AM = Li, Na, and K, respectively. The results, on the other hand, show that up to 12 Li and 6 Na or K atoms can be anchored on the exterior surface of the C60 fullerene simultaneously, each of which can interact with a 5FU molecule. Because of the moderate adsorption energies and charge-transfer values, the 5FU can be simply separated from the fullerene at ambient temperature. Furthermore, the results show that the 5FU may be easily protonated in the target cancerous tissues, which facilitates the release of the drug from the fullerene. The inclusion of solvent effects tends to decrease the 5FU adsorption energies in all 5FU-fullerene complexes. This is the first report on the high capability of AM decorated fullerenes for delivery of multiple 5FU molecules utilizing a C60 host molecule.

Sc-functionalized porphyrin-like porous fullerene for CO2 storage and separation: A first-principles evaluation.

In recent years, there has been a lot of interest in capturing and storing carbon dioxide (CO2) on porous materials as an efficient method for decreasing the adverse effects of this greenhouse gas on the environment and climate change. The current work introduces a Sc-decorated porphyrin-like porous fullerene (Sc6@C24N24) as an efficient material for CO2 capture, storage, and separation using density functional theory calculations. While CO2 is physisorbed over pristine C24N24, the addition of Sc atoms on the N4 sites of C24N24 greatly enhances CO2 adsorption energy. Each Sc atom in Sc6@C24N24 may adsorb up to three CO2 molecules, resulting in a gravimetric density of 48%. Moreover, temperature may be used to modulate CO2 adsorption/desorption over the substrate. The Sc-decorated C24N24 fullerene exhibits a lower affinity for adsorbing N2, CH4, and H2 molecules than CO2. As a consequence, this material might be considered for purifying CO2 molecules from CO2/N2, CO2/CH4, and CO2/H2 mixtures. This study also sheds light on the nature of the Sc-CO2 interaction as well as the underlying mechanism of selective CO2 adsorption on Sc decorated C24N24.

A DFT investigation into the effects of As-doping on the electronic structure and electrochemical activity of pyrite (FeS2).

Pyrite (FeS2) is a semiconductor mineral with electronic structural properties that are heavily influenced by trace elements in its composition. It has been demonstrated experimentally that the reduction of Fe3+ ions is significantly enhanced in the presence of trace arsenic (As) atoms in FeS2. Using density functional theory calculations, we compare the geometric and electronic structural properties of pure and As-doped (110) pyrite surfaces. The interaction of the Fe3+ ion, a common oxidant of sulfides in acidic solution and acid mine drainage, with the aforementioned surfaces is thoroughly investigated. The findings reveal that the addition of an As atom alters the electronic structure of pyrite and decreases its band gap. The adsorption energy of the Fe3+ ion on As-doped pyrite is greater than that on pure pyrite. The calculated Gibbs free energy changes show that the reduction of Fe3+ to Fe2+ ion on the As-modified surface is thermodynamically more favorable than on pure pyrite.

Ca functionalized N-doped porphyrin-like porous C60 as an efficient material for storage of molecular hydrogen.

It is widely known that decorating metal atoms on defective carbon nanomaterials is a useful approach to enhance the hydrogen storage capacity of these systems. Herein, density functional theory calculations are used to determine the H2 storage capacity of Ca functionalized nitrogen incorporated defective C60 fullerenes (Ca6C24N24). The strong binding, uniform distribution, and significant positive charges of the Ca atoms make this system effective material for storage of H2. Ca6C24N24 may adsorb a maximum of 6 hydrogen molecules per Ca atom, yielding a total gravimetric density of 7.7 wt %.

Defect engineering-induced porosity in graphene quantum dots embedded metal-organic frameworks for enhanced benzene and toluene adsorption.

The emerging environmental issues necessitate the engineering of novel and well-designed nanoadsorbents for advanced separation and purification applications. Despite recent advances, the facile synthesis of hierarchical micro-mesoporous metal-organic frameworks (MOFs) with tuned structures has remained a challenge. Herein, we report a simple defect engineering approach to manipulate the framework, induce mesoporosity, and crease large pore volumes in MIL-101(Cr) by embedding graphene quantum dots (GQDs) during its self-assembly process. For instance, MIL-101@GQD-3 (Vmeso: 0.68 and Vtot: 1.87 cm3/g) exhibited 300.0% and 53.3% more meso and total pore volume compared to those of the conventional MIL-101 (Vmeso: 0.17 and Vtot: 1.22 cm3/g), respectively, resulting in 1.7 and 2.8 times greater benzene and toluene loading at 1 bar and 25 °C. In addition, we found that MIL-101@GQD-3 retained its superiority over a wide range of VOC concentrations and operating temperature (25-55 °C) with great cyclic capacity and energy-efficient regeneration. Considering the simplicity of the adopted technique to induce mesoporosity and tune the nanoporous structure of MOFs, the presented GQD incorporation technique is expected to provide a new pathway for the facile synthesis of advanced materials for environmental applications.

Catalytic CO oxidation reaction over N-substituted graphene nanoribbon with edge defects.

Density functional theory calculations, including dispersion effects, are used to demonstrate how substitutional nitrogen atoms can improve the catalytic reactivity of graphene nanoribbons (GNR) with edge defects in the CO oxidation process. It is demonstrated that the addition of nitrogen impurities significantly enhances O2 adsorption on GNR. Carbon atoms near the edges of defects are the most active sites for capturing O2 molecules. The lower adsorption energy of CO relative to O2 implies that the N-modified GNR is resistant to CO poisoning. The Eley-Rideal (E-R) mechanism has activation energies as low as 0.38 eV, making it the most energetically relevant pathway for the CO + O2 reaction. The findings of this study might help in the design of catalysts for metal-free catalysis of CO oxidation.

Y-shape structured azo dyes with self-transforming feature to zwitterionic form as sensitizer for DSSC and DFT investigation of their photophysical and charge transfer properties.

Two novel azo dyes with D-π-A-π-D structures were designed and synthesized to investigate the relationship between molecular structure and sensitizing performance on applying for dye-sensitized solar cells (DSSCs) in comparison with their linear counterparts. Introducing hydroxyl auxiliary groups and arranging π-conjugation length as two parallel and series structural architectures, Y-shape and linear, led to red shift in absorption wavelength and increase in absorption intensity for the Y-shape pattern providing an efficient charge transfer pathway and improved Jsc and η of the DSSCs. Emerging a zwitterionic form, azonium structure, of the sensitizer in parallel configuration for the dyes 1a.p and 1b.p, enhanced light absorption domain and changed anchoring fashion could engendering improved electronic overlapping. The easily-synthesized dyes were evaluated for photophysical and electrochemical properties and turned out that the parallel-decorated dyes displayed better results than the series types as photosensitizers for DSSCs. ATR and Raman spectra clearly showed the adsorption of these dyes on the TiO2 surface. Operational tests of DSSCs, coated by titled azo dyes, illustrated that decorating π-conjugation pattern as parallel structure as well as accessorizing the donor unit with hydroxyl groups improved the photovoltaic performance. Optimized band gap due to participating the azonium structure and restricted electron recombination as well as rectified dye regeneration were proposed as main elements in enhancing performance parameters. A higher solar conversion efficiency was recorded for DSSCs based on the Y-shape dyes compared to other meta azo dye-based cells that were previously reported. Computational calculations were used to corroborate the opto-electrochemical traits of the dyes with a special concern on the influence of structural pattern on photovoltaic features.

Molecular dynamics simulations of choline chloride and phenyl propionic acid deep eutectic solvents: Investigation of structural and dynamics properties.

The prediction of deep eutectic composition is hard and so far, has been distinguished by trial and error. Therefore, in this work, molecular dynamics simulations were performed for specifying the composition of the eutectic point of phenyl propionic acid (Phpr) and choline chloride (ChCl) mixtures. The distinctive properties of the Phpr and ChCl eutectic mixture at the composition of the eutectic point were investigated and were compared to other eutectic mixtures with the different mole fractions of Phpr and ChCl. Structural properties such as radial distribution function (RDF), coordination number, hydrogen-bond number, interaction energies, and dipole moment of species, as well as dynamical properties such as mean square displacement (MSD), viscosity, and self-diffusion coefficient were analyzed. The obtained results of structural properties indicated that each chloride anion is surrounded by two Phpr molecules for deep eutectic point states that is in good agreement with available experimental reports. Moreover, the viscosity of studied mixtures evaluated by the Green-Kubo method was found to be consistent with the reported experimental data. Besides, the stress-autocorrelation function (SACF) and convergency of viscosity with time were calculated. Finally, the eutectic point could be detected by the changes in the trends of total van der Waals interaction energies and the viscosity.

Synergic effects between boron and nitrogen atoms in BN-codoped C59-n BN n fullerenes (n = 1-3) for metal-free reduction of greenhouse N2O gas.

The geometries, electronic structures, and catalytic properties of BN-codoped fullerenes C59-n BN n (n = 1-3) are studied using first-principles computations. The results showed that BN-codoping can significantly modify the properties of C60 fullerene by breaking local charge neutrality and creating active sites. The codoping of B and N enhances the formation energy of fullerenes, indicating that the synergistic effects of these atoms helps to stabilize the C59-n BN n structures. The stepwise addition of N atoms around the B atom improves catalytic activities of C59-n BN n in N2O reduction. The reduction of N2O over C58BN and C57BN2 begins with its chemisorption on the B-C bond of the fullerene, followed by the concerted interaction of CO with N2O and the release of N2. The resulting OCO intermediate is subsequently transformed into a CO2 molecule, which is weakly adsorbed on the B atom of the fullerene. On the contrary, nitrogen-rich C56BN3 fullerene is found to decompose N2O into N2 and O* species without the requirement for activation energy. The CO molecule then removes the O* species with a low activation barrier. The activation barrier of the N2O reduction on C56BN3 fullerene is just 0.28 eV, which is lower than that of noble metals.

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.

CuN3 doped graphene as an active electrocatalyst for oxygen reduction reaction in fuel cells: A DFT study.

Based on first-principles DFT calculations, copper-nitrogen embedded graphene (CuN3-Gra) is introduced as an efficient electrocatalyst for oxygen reduction reaction (ORR) in fuel cells. The possible reaction mechanisms as well as the corresponding stationary points on potential energy surfaces are studied in acidic media. Our results indicate that dissociation of O2 over CuN3-Gra cannot occur at normal condition due to its large energy barrier. In contrast, the O2 hydrogenation into OOH, followed by the hydrogenation of OOH into O and H2O species is the most favorable pathway for the ORR process. The energy barrier for rate-determining step of this reaction is calculated to be 1.00 eV which is related to the formation of first H2O molecule. The free energy diagrams reveal that for OOH hydrogenation pathway, all of the elementary steps are exothermic at potentials 0.0-0.8 V.

Preparation and characterization of a new waste-derived mesoporous carbon structure for ultrahigh adsorption of benzene and toluene at ambient conditions.

In this work, a series of nanoporous carbon materials were synthesized using Iranian asphaltene as a low-cost carbon source and modified by melamine as a new nitrogen-rich promoter (M-IANC). The adsorption capacity of benzene and toluene on the synthesized M-IANCs was measured at low and high concentrations by an in-house built apparatus. The results demonstrated that the addition of melamine remarkably increased the mesoporous volume (up to 1.61 cm3/g) in the nanoporous carbon structure and, subsequently, created a large surface area (2692 m2/g) and pore volume (1.71 cm3/g). The resulting M-IANC-C nanostructure (melamine:PIA mass ratio of 1:2) depicted 228.18 wt.% and 82.08 wt.% adsorption capacity for benzene and toluene, respectively, which were 19.4 and 2.8 times higher than commercial activated carbon. In addition to the distinguished adsorptive behavior for benzene and toluene removal, M-IANC-C exhibited higher cyclic adsorption capacity than those of unmodified IANC sample after four consecutive cycles. The adsorption mechanism and the role of melamine groups in the adsorption of benzene and toluene were also studied by the density functional theory (DFT) calculations. Besides the inexpensive cost of the carbon source (asphaltene), results also indicate that the M-IANC can be a suitable candidate for VOC adsorption.