COCl2 Molecule Research Articles

Ab initio study of Ti-doped C3N nanosheet as COCl2, O3, and HCN gas sensor

In the present study, we designed the pristine C3N and Ti-doped C3N nanosheets to investigate the geometrical, electrical, and optical properties using density functional theory calculation. The negative value of the cohesive energy of both nanosheets indicates the structures are energetically stable. Ti-doping in C3N results in a conductor-to-semiconductor transition with a band gap of 0.15 eV. We studied the adsorption of COCl2, O3, and HCN gas molecules on the designed structures. The adsorption energy for COCl2, O3, and HCN gases significantly increased to −8.63, −9.80, and −5.98 eV respectively after Ti-doping. A significant variation in the band gap of Ti-doped C3N is observed due to gas adsorption. The complex structures show a high absorption coefficient of over 104 cm−1 in the visible range with a significant red/blue shifting of absorption peaks. The study proves the Ti-doped C3N to be a potential candidate for sensing COCl2, O3, and HCN gases.

Li-decorated B12C6N6 hybrid nanocage for sensing Cl2, COCl2, H2S and NH3 gas molecules

We examined the gas sensing abilities of Li-decorated B12C6N6 (B12C6N6Li) hybrid nanocage, introducing B12C6N6 for the first time in sensing applications. The toxic gas molecules like Cl2, COCl2, H2S, and NH3 were considered. The B12C6N6 nanocage with C2V symmetry displayed the lowest energy among its isomers. Li exhibited stronger anchoring above B3C2N ring compared to B2C2, B2N2, and B3CN2 rings of B12C6N6 nanocage, displaying a binding energy of −3.30 eV. Li decoration resulted in asymmetric spin-up and spin-down states near Fermi level, indicating magnetic nature of complexes. B12C6N6, an electron-deficient nanocage, displayed charge transfer from Li atom to the nanocage. Substantial changes in electronic states occurred following the adsorption of Cl2 and COCl2 molecules. COCl2, H2S, and NH3 adsorption is thermodynamically favourable over a wide temperature and pressure range, while Cl2 adsorption is favourable only within a confined range. Earlier findings indicate dissociative adsorption of Cl2 on nanocages rendering the substrate to be non-reusable. B12C6N6Li considered here is superior over other nanocages as Cl2 adsorbs in molecular form while B12C6N6Li also demonstrates significant sensitivity. B12C6N6Li nanocage is unsuitable for sensing H2S and NH3 gas molecules but holds promise as a potential candidate for sensing Cl2 and COCl2 gas molecules.

A theoretical investigation of the competition between σ- and π-holes on the stability of the complexes resulting from the interaction between the COCl2 and OCY molecules (Y = S, Se, and Te)

Carbonyl dichloride (COCl2), also known as phosgene, is a highly toxic gas, whose exposure or acute inhalation causes severe respiratory complications, such as pulmonary edema, pulmonary emphysema, and even death. In this study, we theoretically investigated the complexes formed by the interaction between the COCl2 (phosgene) and OCY molecules (Y = S, Se, and Te). Complex geometry optimization yielded three distinct types of conformations. Conformation-I complexes were stabilized by two concurring chalcogen-bonding interactions (i.e. O⋯Y and Cl⋯Y) by forming a ring structure. However, only a single linear interaction (O⋯C) or (O⋯Cl) occurred in conformation-II and III complexes, forming complexes with the nature of tetrel and halogen bonds, respectively. According to the results of the molecular electrostatic potential (MEP), interaction energy (ΔET), natural bond orbital (NBO), and so on, the σ-hole of the Y atom in the OCY molecule exhibited higher acidic strength and formed more stable complexes than those resulting from the σ- and π-holes of the COCl2 molecule.

Adsorption, sensing, electronic and magnetic properties of phosgene (COCl2) molecule adsorbed on Nb-doped arsenene: First-principles study

In this study, using first-principles calculations, the adsorption of phosgene (COCl2) molecule on pristine arsenene (p-As) and Nb-doped arsenene (Nb–As) was investigated theoretically by means of density functional theory (DFT) calculations. The results showed that COCl2 molecule is physically adsorbed with no significant effect on the electronic properties of arsenene. The introduction of Nb-atom into arsenene turned it to a magnetic semiconductor with a magnetic moment of 2.0 μB. The Nb-As system demonstrated strong interaction toward the gas molecule. The COCl2 molecule was chemically adsorbed on Nb–As accompanied by large adsorption energy (up to −2.87 eV) and charge transfer from the adsorbent to the molecule. Furthermore, the work function and electrical conductivity of Nb–As were found significantly tuned by the adsorption of phosgene molecule, promising the potential of Nb–As for sensing toxic phosgene gas.

Metal-Decorated Phthalocyanine Monolayer as a Potential Gas Sensing Material for Phosgene: A First-Principles Study.

Research into a gas sensing material with excellent performance to detect or remove toxic phosgene (COCl2) is of great significance to environmental and biological protection. In the present work, the adsorption performance of COCl2 on pristine phthalocyanine (Pc) and metal-decorated Pc (MePc, Me = Cu, Ga, and Ru) monolayers was studied by first-principles calculations. The results show that the absorption process of COCl2 on pristine Pc and CuPc both belong to physisorption, indicating that they are not suitable gas sensing materials for COCl2. When Pc sheets are decorated by Ga and Ru atoms, the adsorption of COCl2 is changed into chemisorption, and the corresponding adsorption energies are −0.57 and −0.50 eV for GaPc and RuPc, respectively. The microcosmic mechanism between COCl2 and adsorbents (GaPc, RuPc) was clarified by the analysis of the density of states, the charge density difference, and the Hirshfeld charge. In addition, the COCl2 adsorption results in a significant conductivity variation of the RuPc monolayer, demonstrating it exhibits a high sensitivity to the COCl2 molecule. Meanwhile, quick desorption processes were noticed at various temperatures for the COCl2/RuPc system. Consequently, the RuPc monolayer can be considered as a potential candidate for phosgene sensors because of the moderate adsorption strength, high sensitivity, and fast desorption speed.

From fundamental to CO2 and COCl2 gas sensing properties of pristine and defective Si2BN monolayers.

In this work, the capability of Si2BN monolayers (Si2BN-MLs) to sense CO2 and COCl2 molecules was investigated by analyzing the structural, electronic, mechanical and gas sensing properties of defect-free and defective Si2BN-ML structures. Electronic property analysis revealed that the Si2BN-ML retains its metallicity in the presence of vacancy defects. The computed vacancy formation energies of Si, B and N monovacancies are 3.25 eV, 2.27 eV and 2.55 eV, respectively, which indicate that the B monovacancy is thermodynamically more feasible. Besides, both pristine and defective Si2BN-ML structures show good mechanical stability. To validate the gas sensing properties, the adsorption energy and charge transfer were analysed, showing that both pristine and defective Si2BN-ML structures receive considerable charges from the CO2 and COCl2 molecules via a stable physisorption process. The work function analysis revealed that a minute increase <0.10 eV is responsible for the enhanced selectivity and sensitivity of Si2BN-ML structures in detecting CO2 and COCl2 molecules. The low adsorption energies of both CO2 and COCl2 gas molecules during the interaction with Si2BN-ML structures signify the possibility of a large number of adsorption-desorption cycles with an ultra-low recovery time, 0.174 ns for CO2 and 0.016 ns for COCl2, suitable for efficient gas sensing applications.

Comparative Study of Phosgene Gas Sensing Using Carbon and Boron Nitride Nanomaterials—A DFT Approach

Phosgene (COCl2), a valuable industrial compound, maybe a public safety and health risk due to potential abuse and possible accidental spillage. Conventional techniques suffer from issues related to procedural complexity and sensitivity. Therefore, there is a need for the development of simple and highly sensitive techniques that overcome these challenges. Recent advances in nanomaterials science offer the opportunity for the development of such techniques by exploiting the unique properties of these nanostructures. In this study, we investigated the potential of six types of nanomaterials: three carbon-based ([5,0] CNT, C60, C70) and three boron nitride-based (BNNT, BN60, BN70) for the detection of COCl2. The local density approximation (LDA) approach of the density functional theory (DFT) was used to estimate the adsorption characteristics and conductivities of these materials. The results show that the COCl2 molecule adsorbed spontaneously on the Fullerene or nanocages and endothermically on the pristine zigzag nanotubes. Using the magnitude of the bandgap modulation, the order of suitability of the different nanomaterials was established as follows: PBN60 (0.19%) < PC70 (1.39%) < PC60 (1.77%) < PBNNT (27.64%) < PCNT (65.29%) < PBN70 (134.12%). Since the desired criterion for the design of an electronic device is increased conductivity after adsorption due to the resulting low power consumption, PC60 was found to be most suitable because of its power consumption as it had the largest decrease of 1.77% of the bandgap.

Theoretical insight into two-dimensional M-Pc monolayer as an excellent material for formaldehyde and phosgene sensing

Design of the good-performance materials for detecting or removing the toxic formaldehyde and phosgene gases is extremely meaningful to environmental conservation and human health. In this work, the density functional theory calculations were employed to investigate the adsorption behaviors and electronic characteristics of H2CO and COCl2 on the pristine and metal doped phthalocyanine monolayers (M-Pc, M = Al, Cr, Mn, Fe, Co and Ni). The results show that the H2CO is dissociation-chemisorbed on pristine Pc monolayer, while the COCl2 molecule is parallelly physisorbed on it, and the inappropriate adsorption strength restrict its application in gas sensor. While doping Al, Cr and Fe atoms into Pc sheet could efficiently regulate the adsorption ability of these two gas molecules, reaching the adsorption energy of −1.26 to −0.63 eV. The origin of strong interactions between gas molecules and Al/Cr/Fe-Pc monolayer are revealed by the analysis of density of state, charge density difference and Mulliken charge. Additionally, the H2CO adsorption results in the obvious change of electrical conductivity and magnetism for Cr-Pc monolayer, and the recovery time of H2CO molecule is predicted to be 0.04 s at room temperature. Therefore, the Cr-Pc monolayer could be a sustainable gas sensor for H2CO detection with excellent selectivity and sensitivity.

Sensing Behavior of Hexagonal-Aluminum Nitride to Phosgene Molecule Based on Van der Waals–Density Functional Theory and Molecular Dynamic Simulation

In this paper, we evaluated adsorption of phosgene gas molecule (COCl2), on the hexagonal-aluminum nitride (h-AlN) nanosheet by using first-principles van der Waals density functional theory calculations (vdW-DF) method. The nature of interaction between the phosgene molecule and h-AlN is discovered by geometries, adsorption energies, Mulliken, Hirshfeld as well as Voronoi charges analyses. The density of states (DOS) was calculated and the results show that HOMO/LUMO energy gap of h-AlN is significantly reduced upon the COCl2 adsorption. The projected density of states (PDOS) of the adsorption systems suggested that the enhancement of adsorption was owing to the hybridization between Al atom of h-AlN sheet and the O atom of phosgene molecule. Interestingly, the results reveal that the Eg of h-AlN is very sensitive to the presence of COCl2 molecule as its value reduces from 3.337 eV in pure h-AlN to 1.966 eV (41.08% change) after the COCl2 adsorption which would result in electrical conductance increment. Global reactivity descriptor values such as electronegativity (χ), global hardness (η), global softness (S), electronic chemical potential (μ), electrophilicity index (ω), and electro accepting power (ω+) were calculated. Additionally, the stability of the most stable phosgene/h-AlN complex was evaluated by means of DFT molecular dynamics (MD) simulation at room temperature under constant volume and temperature conditions with PBE method. Based on the DFT calculation results, the h-AlN nano sheet is expected to be potential novel sensor for detecting the presence of COCl2 gas.

Remarkable improvement in phosgene detection with a defect-engineered phosphorene sensor: first-principles calculations.

This paper has addressed the monitoring of phosgene (COCl2) via pristine (BP) and defective (DP) phosphorene monolayer nanosensors at the HSE06/TZVP level of theory. The most stable structures of phosgene preferred planar configurations, which were parallel to the surface. Overall, the defect-engineered nanosensor was highly sensitive (726% gas sensitivity) and reusable (0.31 ns recovery time at room temperature) for phosgene detection. DP was a better work-function sensor of COCl2 compared to BP. The gas response was enhanced by a factor of 54 with vacancy doping. Furthermore, the selectivity of the defect-engineered phosphorene was predicted to be extremely high in both dry and humid air. Such improvements open new opportunities for the rational design of novel and reusable 2D sensors for the detection of toxic COCl2 molecules.

The AIM, RDG, NBO, Quantum and Structural Study of Adsorption of Phosgene Gas on the Surface of Pristine and Al, P Doped Ga12N12 Nano Cluster: A DFT Method

The main objective of this work is to study the sensivity of pristine, Al, P and Al & P doped Ga12N12 to adsorb phosgene (COCl2) molecule. The interaction of COCl2 from O, C and Cl sites on the surface of Ga12N12 is investigated by applying the density functional theory (DFT) at the cam-B3LYP/6-31G(d) level of theory. The geometrical and electrical structures, quantum descriptive, thermodynamic parameters, solvent effect, atom in molecule theory (AIM), natural bond orbital (NBO), and the reduced density gradient (RDG) are calculated at the above level of theory. The calculated results indicate that the adsorption of COCl2 on the surface of pristine and Al, P and Al & P doped Ga12N12 is exothermic, as well as Al-doped Ga12N12 is more favorable than P and Al & P doped. The recovery time results for adsorption of COCl2 from O site on the surface of Ga12N12, Al-Ga11N12, Ga12N11P and Al-Ga11N11P are 0.103, 4.69×10-7, 3.81×10-12 and 4.31×10-7 respectively. As a result, these nanoclusters can be used as sensor devices toward COCl2 molecule. The deformation energy results reveal that the structural change of Ga12N12 and COCl2 at all adsorption states are not significant. The AIM, RDG and NBO results demonstrate that the intermolecular interaction from O site of COCl2 on the surface of pristine, Al, P and Al & P doped Ga12N12 is stronger than C and Cl atoms sites of COCl2 as it is an electrostatic attractive type. The main objective of this work is to study the sensivity of pristine, Al, P and Al & P doped Ga12N12 to adsorb phosgene (COCl2) molecule. The interaction of COCl2 from O, C and Cl sites on the surface of Ga12N12 is investigated by applying the density functional theory (DFT) at the cam-B3LYP/6-31G(d) level of theory. The geometrical and electrical structures, quantum descriptive, thermodynamic parameters, solvent effect, atom in molecule theory (AIM), natural bond orbital (NBO), and the reduced density gradient (RDG) are calculated at the above level of theory. The calculated results indicate that the adsorption of COCl2 on the surface of pristine and Al, P and Al & P doped Ga12N12 is exothermic, as well as Al-doped Ga12N12 is more favorable than P and Al & P doped. The recovery time results for adsorption of COCl2 from O site on the surface of Ga12N12, Al-Ga11N12, Ga12N11P and Al-Ga11N11P are 0.103, 4.69×10-7, 3.81×10-12 and 4.31×10-7 respectively. As a result, these nanoclusters can be used as sensor devices toward COCl2 molecule.

Computational quest of adsorbents based on doped graphene nanosheets for phosgene uptake, and analysis of the co-adsorption phenomena

A density functional theory study was performed to analyse the interaction of COCl2 onto A-doped graphene nanosheets (AG, where A: Al, Si, Ti, Cr, Mn, Fe). Adsorption configurations, adsorption energies, electronic properties, and the interaction in a co-adsorption regime were characterised in detail for all the adsorbent-adsorbate complexes. The results show that these materials are excellent COCl2 adsorbents, with adsorption energies of up to 1.1 eV/molecule and remarkable changes in the electronic properties. The changes in the adsorption stability in a co-adsorption regime indicates that TiG and CrG are efficient adsorbents at low and high relative COCl2 concentrations; while, AlG, MnG and FeG will be efficient only at low relative COCl2 concentrations, where the adsorption stability per COCl2 molecule significantly decreases with respect to the single adsorption. Otherwise, the COCl2 adsorption and electronic response in aerobic environments was found to be suitable only for CrG and MnG, where the electronic response is based on the recognition of the [COCl2]δ+–dopant–[O2]δ− intermediate. This work allows to propose new graphene-based materials for the adsorption, filtration, and/or collection of toxic COCl2.

A new flatland buddy as toxic gas scavenger: A first principles study

Recently predicted and grown new single element two dimensional (2D) material borophene gathered tremendous research interest due to its structural, electronic and other properties. Using first principles based dispersion corrected density functional calculations, we have studied interaction of two toxic gases phosgene (COCl2) and carbon monoxide (CO) with borophene to understand the role of borophene as biosensor and carriers in drug delivery. The sensing behaviour of borophene towards COCl2 and CO has been studied by calculating the binding energy and electronic density of states (DOS). The change in the band structure, DOS, charge density and work function (WF) upon adsorption of gas molecules further confirms the sensing properties of borophene towards these molecules. The binding energy for COCl2 and CO molecules on borophene is −0.306 eV and −0.15 eV respectively which indicates that the COCl2 is adsorbed more favourably than CO over borophene. The WF is enhanced by 0.193 eV and 0.051 eV after the adsorption of COCl2 and CO over borophene. Short recovery time of 148 ns and 37 ns for COCl2 and CO has been predicted. These findings show that the borophene can be used as nanosensor to detect COCl2 and CO.

Molecular dynamics simulation and quantum chemical studies on the investigation of aluminum nitride nanotube as phosgene gas sensor

The present work utilizes density functional theory (DFT) and molecular dynamics (MD) calculations to investigate the adsorption process of phosgene (COCl2) molecule on the pristine aluminum nitride nanotube (AlNNT). Quantum chemical calculations by DFT provide detailed geometrical parameters, electronic properties and the adsorption energies for the AlNNT and five different COCl2 configurations on the nanotube. DFT calculations confirmed the energetic stability of the optimized geometries and revealed that COCl2 molecule adsorbed on the pristine AlNNT through weak van der Waals (vdW) interaction, which means that the adsorption is physisorption process. The results of the theoretical investigations show that the adsorption of the COCl2 molecule on the nanotube surface results in a decrease the energy gap (Eg). Thus, the reactivity and electrical conductivity increase upon the adsorption process. Moreover, the reliable assessment of the dynamic adsorption of various air pollutant gas molecules i.e., carbon dioxide (CO2), carbon monoxide (CO), nitrous oxide (N2O), nitrogen dioxide (NO2) and phosgene on the nanotube surface is examined by complementing traditional analysis of MD simulations, such as the time-evolution of the root mean square deviation (RMSD), radial distribution functions (RDF), the number of gas molecules and number of contacts, along with the energetics profiles. Furthermore, close inspection of the results of RDF patterns and the van der Waals energy calculations implies the remarkable interaction between phosgene molecule and nanotube surface. According to the molecular dynamics simulation study, it can be concluded that AlNNT can be a promising candidate in gas sensor devices for detecting the COCl2 molecule.

Investigation of the molecular structure, electronic properties, AIM, NBO, NMR and NQR parameters for the interaction of Sc, Ga and Mg-doped (6,0) aluminum nitride nanotubes with COCl2 gas by DFT study

In order to search for a novel sensor to detect and control exposure to phosgene (COCl2) molecule, the reactivities of pristine, Sc, Ga and Mg-doped (6,0) single-walled aluminum nitride nanotubes (AlNNTs) towards the COCl2 molecule are investigated by performing density functional theory calculations. It is found that the COCl2 molecule presents strong physisorption on the Mg and Sc-substituted Al defect sites, which is in contrast to its weak physisorption on pristine and Ga-doped AlNNTs. The AIM theory has been also used to examine the properties of the bond critical points: their electron densities and Laplacians. The nature of charge transfer between the oxygen atom of COCl2 and the impurity atoms is clarified. Natural bond orbital analysis reveals that the electronic configuration of the doped Mg metal represents a prominent change with respect to that of the Sc and Ga atoms. Also, the interaction of COCl2 gas and pristine/doped AlNNTs on the basis of four reactivity descriptors such as the overall stabilization energy (ΔESE), the individual energy change of acceptor (ΔEA(B)), the individual energy change of donor (ΔEB(A)) and charge transfer (ΔN) have been explained. We found that substituting an Al atom by Mg makes the electronic properties of the AlNNT strongly sensitive to the COCl2 molecule. Due to physisorption, NMR and NQR parameters of the adsorption sites are also altered. Density of the state investigation suggests that the Mg doping induces main changes in the electronic structure pattern of the interaction of phosgene gas with AlNNT.

Adsorption of COCl2 gas molecule on armchair boron nitride nanoribbons for nano sensor applications

First-principle calculations under the framework of density functional theory have been performed to study the adsorption of COCl2 (Phosgene) gas molecule on armchair boron nitride nanoribbon (ABNNR). Depending upon the geometry of the ribbon, we have considered two possible cases for adsorption of guest molecule i.e. adsorption at closed edge and adsorption at open edge. Adsorption energy (Ead) calculations implies that adsorption at open edge is energetically more favorable compared to closed edge case. The formation of closed ring structure at the open edge in this case also accounts for its stability. Electronic properties reveal that with the adsorption of COCl2 molecule on ABNNR the semiconducting behavior remains intact but a significant modulation in the band gap is observed as compared to bare ribbon. The current voltage (I–V) characteristics have also been investigated using non-equilibrium green’s function (NEGF) approach. The results indicate towards the potential applicability of ABNNR for sensing the toxic COCl2 gas.

Synthesis and characterization of cobalt chloride/poly(ethylene oxide) electrospun hybrid nanofibers

Cobalt chloride (CoCl2)/poly(ethylene oxide) (PEO) hybrid nanofibers with diameters ranging from 500 to 700 nm were successfully synthesized by a simple and versatile approach of electrospinning. The CoCl2/PEO hybrid nanofibers were studied by different techniques such as Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared (FTIR) and Thermogravimetric Analysis (TGA). One dimensional (1-D) surface roughness average (Ra1-D) along a typical nanofiber was analyzed to be 57 nm. The chemical interactions between the CoCl2 and PEO molecules showed that polar environment provided by CoCl2 for the PEO molecules aided the modification of CoCl2 molecule configuration.

The dissociative excitation of cobalt atom even sextet levels in collisions of electrons with CoCl2 molecules

The cross sections of dissociative excitation of 46 transitions from cobalt atom even sextet levels in collisions of electrons with CoCl2 molecules were measured at an exciting electron energy of 100 eV. The dissociative and direct CoI excitation cross sections were compared. The results were used to calculate the total cross sections of dissociative excitation of CoI levels at an electron energy of 100 eV. Possible reaction channels at low electron energies are discussed.

CoCl+: Unique in all of molten saltdom?

The UV-vis spectra of CoCl2 dissolved in molten NaCl-AlCl3 solutions were obtained as a function of composition from slightly basic compositions to fairly acidic compositions, and the solubility of CoCl2 was determined using both an analytical technique and an electromotive force (EMF) technique. The cell used for the EMF measurements was Co/CoCl2-NaAlCl4//NaAlCl4-(AgCl) N /AgCl (s)Ag, where the mole fraction, N, is fixed. Saturation at 175°C was detected when [δE/δN(CoCl2)] T =0. A very sharp minimum in the solubility was found in the vicinity of the 50.00 pct NaCl-50.00 pct AlCl3 composition, and a distinct spectrum with three broad peaks belonging to neither tetrahedrally nor octahedrally coordinated Co++ was obtained in this composition region. In this composition region, the solution can be described in terms of five cobalt-containing species of the form CoCl n 2−n , where n=0→4, indicating that the solubility of CoCl2 in the NaAlCl4 melt is related to the formation of chlorometallic species that are present in much higher concentration than Co++ ions with no bound Cl− ions, but which are solvated with AlCl 4 − ions. In the composition range where a unique three-peaked spectrum was observed, the dominant species is the CoCl+ ion. The other significant species could be the neutral CoCl2 molecule. All of the other cobalt-containing species are present at such low concentrations that their spectra do not appear. We think that the asymmetric CoCl+ species is responsible for the observed spectrum because it is present in much higher concentration than any other species, and it is a stronger absorber of light in the UV-vis region of the spectrum than is the CoCl2. As far as we can discern, this is the only completely asymmetric species that has been identified spectroscopically as existing in an inorganic molten salt solution.

Isotopically selective dissociation of COCl2molecules under the action of NH3laser radiation

An experimental study was made of the yield and selectivity of dissociation of COCl2 molecules by NH3 laser radiation pulses of ~ 4 μs duration.The dissociation was found to involve competition between radiative and collisional activation of molecules and the dissociation yield was determined by the latter activation process.