Adsorption Of Formaldehyde Molecule Research Articles

CH<sub>2</sub>O Adsorption on M (M = Li, Mg and Al) Atom Deposited ZnO Nano-Cage: DFT Study

The structural and electronic properties of Li, Mg and Al deposited ZnO nanocages and their effects on the adsorption of formaldehyde molecule have been investigated using the density functional theory (DFT) computations. To understand the behavior of the adsorbed CH2O molecule on the ZnO nanocage, results of DFT calculations of the M-deposited nanocages (M=Li, Mg and Al), as well as complex systems consisting of the adsorbed CH2O molecule on M-deposited ZnO nanocage were reported. The results presented include adsorption energies, bond lengths, electronic configurations, density of states and molecular orbitals. It was found that, the most energetically stable adsorption configurations of CH2O molecule on the bare ZnO leads to 12% dilation in C=O bond length of CH2O and 14% decrease in HOMO-LUMO gap of ZnO cluster. The most energetically stable adsorption configurations of CH2O molecule on Li, Mg and Al-deposited ZnO lead to 4%, 4% and 11% dilation in C=O bond length of CH2O and-0.66, -45 and , +66% change in HOMO-LUMO gap of ZnO nanocages, respectively. The interaction between CH2O with bare ZnO and M-deposited ZnO nanocages is attributed to charge transfer mechanism. These results may be meaningful for CH2O degradation and detection.

Adsorption of formaldehyde molecule on the pristine and transition metal doped graphene: First-principles study

The adsorption of H2CO molecule on pristine and transition metal (Ti and V) doped graphene samples were investigated via a first-principles approach based on density functional theory. The most stable adsorption geometry, energy and charge transfer of H2CO molecule on pristine and doped graphene are discussed respectively. We have found that Ti and V dopant atoms can significantly enhance the interaction between H2CO molecule and graphene. The calculated net electron transfers, electronic density difference images and densities of states give the evidence that the H2CO molecules stay on Ti (orV) – doped graphene by chemisorption. After H2CO adsorption, there are significant changes in electronic structure near the Fermi level, for both two systems of Ti and V doped graphene. This indicates distinct changes of electron transport properties. We have also found that H2CO molecule has a larger absorption energy on V-doped graphene (1.939eV) compared with Ti-doped graphene (1.120eV). It is shown that the Ti-doped graphene has enough binding energy, adequate changes in electronic structure and reasonable short recovery time 10−3s, making it a promising candidate for detecting formaldehyde gas.

Chemisorption of CH2O on N-doped TiO2 anatase nanoparticle as modified nanostructure media: A DFT study

The structural and electronic properties of N-doped TiO2 anatase nanoparticles and their effects on the adsorption of formaldehyde molecule have been investigated using the density functional theory computations. Given the need to better understand the behavior of the adsorbed CH2O molecule on the anatase nanoparticle, we report results of density functional theory studies of the N-doped nanoparticles, as well as complex systems consisting of the CH2O molecule bound to a TiO2 nanoparticle. N-doped nanoparticle was obtained by substitution of nitrogen atom of TiO2 instead of oxygen atom. Adsorptions of the CH2O molecule on the dangling oxygen atom, twofold coordinated oxygen atom and doped nitrogen atom sites of the pristine and N-doped anatase nanoparticles were investigated. The results presented include structural parameters such as adsorption energies, bond lengths and bond angles and electronic properties such as density of states, spin distribution densities and molecular orbitals. It was found that the adsorption of the CH2O molecule on the dangling oxygen of considered N-doped TiO2 anatase nanoparticles is energetically more favorable than the adsorption on the undoped ones. It means a more stable configuration compared to the undoped nanoparticle adsorption, but not as stable as the CH2O adsorption on the doped nitrogen site of N-doped nanoparticles.

A DFT study on the formaldehyde (H2CO and (H2CO)2) monitoring using pristine B12N12 nanocluster

The interaction between formaldehyde monomer (H2CO) as well as dimer ((H2CO)2) and pristine B12N12 nanocluster is investigated at B3LYP/6-311++G(d,p) level of theory. It is found that in contrary to the pristine boron nitride nanotube and nanosheet, formaldehyde adsorption induce considerable variation in the electronic properties of the B12N12 nanocluster. Also it is shown that the pristine B12N12 cluster could adsorb up to four monomer and three dimer of formaldehyde molecules in which the HOMO–LUMO gap decreased about 38–55%. Since the conductivity of the B12N12 nanocluster changes by the adsorption of formaldehyde molecules, the presence of this toxic gas could be detected. The Bader theory of atoms in molecules (AIM) is also applied to analyze the interaction of formaldehyde with nanocluster. It is suggested pristine B12N12 nanocluster could be a promising candidate for detecting formaldehyde molecule. The results indicate that B12N12 may be a promising chemical sensor for detection of formaldehyde molecule.

Adsorption of formaldehyde molecule on Stone–Wales defected graphene doped with Cr, Mn, and Co: A theoretical study

Adsorption of H2CO molecule on Cr, Mn and Co doped Stone–Wales defected graphene were theoretically studied using density functional theory (DFT) method. It was found that H2CO molecule had no considerable interaction with perfect or SW-defected graphene, but the presence of Stone–Wales defect in graphene enhanced the adsorption of H2CO, which exhibited larger binding energy and smaller bond distance. Chemisorptions were observed on the transition metal (TM) atoms (Cr, Mn and Co) doped structures. Compared with TM-doped perfect graphene, the binding energy of H2CO molecule on TM-doped defective graphene can be enlarged by the introduction of SW-defect. The density of states (DOS) showed that the contribution of hybridization between O atom of H2CO molecule and transition metal atom is mainly from the p or d orbitals. Furthermore, adsorption of H2CO affected the electronic conductance of the Cr and Mn doped defective graphene, which can be seen signal of gas sensor. It is expected that the results could provide useful information for the design of H2CO sensing devices.

Adsorption of formaldehyde molecule on Al-doped vacancy-defected single-walled carbon nanotubes: A theoretical study

The interactions between formaldehyde (H2CO) and modified (8,0) single-walled carbon nanotubes, including Al doping, vacancies, and a combination of these two, were investigated using the density functional theory (DFT) method. It was found that H2CO adsorption on vacancy-defected CNTs had relatively higher adsorption energy and shorter binding distance compared with the perfect one. Furthermore, there existed a strong chemical adsorption between H2CO molecule and Al-doped defected CNTs, which exhibited more active interaction and larger net charge transfer than that of defected CNTs without Al-doped. The spin polarized electronic density of states (PDOS) of the adsorption systems suggested that the enhancement of adsorption was due to the hybridization between Al atom and the C atoms at the vacant sites. Therefore, Al-doped vacancy-defected CNTs could be expected to be novel chemical sensors for detecting H2CO gas.

Adsorption of formaldehyde molecule on the intrinsic and Al-doped graphene: A first principle study

To search for a high sensitivity sensor for formaldehyde (H2CO), we investigated the adsorption of H2CO on the intrinsic and Al-doped graphene sheets using density functional theory (DFT) calculations. Compared with the intrinsic graphene, the Al-doped graphene system has high binding energy value and short connecting distance, which are caused by the chemisorption of H2CO molecule. Furthermore, the density of states (DOS) results show that orbital hybridization could be seen between H2CO and Al-doped graphene sheet, while there is no evidence for hybridization between the H2CO molecule and the intrinsic graphene sheet. Therefore, Al-doped graphene is expected to be a novel chemical sensor for H2CO gas. We hope our calculations are useful for the application of graphene in chemical sensor.

Adsorption of formaldehyde molecule on the pristine and silicon-doped boron nitride nanotubes

The adsorption of formaldehyde (HCOH) molecule on the pristine and silicon-doped (Si-doped) single-walled (8, 0) boron nitride nanotubes (BNNTs) is investigated using density functional theory (DFT) calculations. Compared with the weak physisorption on the pristine BNNT, the HCOH molecule presents strong chemisorption on both silicon-substituted boron defect site and silicon-substituted nitrogen defect site of the BNNT, as indicated by the calculated geometrical structures and electronic properties for these systems. It is suggested that the Si-doped BNNT presents high sensitivity to toxic HCOH. Based on calculated results, the Si-doped BNNT is expected to be a potential novel sensor for detecting the presence of HCOH.

Anodic Oxidation Behaviors of Formaldehyde at Boron‐Doped Diamond Electrodes

AbstractThe electrochemical behaviors of formaldehyde (FA) at boron‐doped diamond (BDD) electrodes are investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear scanning voltammetry (LSV) techniques. The CV results show that the oxidation reaction of FA is influenced by the hydroxyl concentration in the solution, and the peak current response with the FA concentration is linear at the range from 10 to 100 mM. The differential capacitance from EIS results indicate that the FA molecules adsorb at the BDD electrode surface at low potential (from 1.0 to 1.4 V). The kinetic studies have been examined with the various concentrations of FA, pH, and temperature. The activation energy of FA oxidation is also calculated. The results of kinetic study indicate that the adsorption of FA molecules at the BDD electrode is the rate‐determining step at low potential (from 1.0 to 1.40 V).