1
|
Tachikawa H. Intracluster reaction dynamics of NO+(H2O)n. J Chem Phys 2024; 161:094306. [PMID: 39230376 DOI: 10.1063/5.0221836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Accepted: 08/15/2024] [Indexed: 09/05/2024] Open
Abstract
Nitric oxide (NO) and NO-water clusters play crucial roles in the D-region of the atmosphere because it is postulated that NO+ reacts with H2O to produce nitrous acid (HONO) and H3O+. HONO is the major precursor of the hydroxyl radicals leading to the formation of secondary pollutants. The sources of atmospheric HONO, however, are not fully understood. Previously, the sequential H2O addition reaction, H2O + NO+(H2O)n, and the bi-molecular collision reaction, NO+ + (H2O)n, have been investigated by both experiments and theoretical calculations to determine the formation mechanism of HONO. However, the photo-reactions from NO(H2O)n neutral clusters were not considered for the formation mechanism of HONO. In this study, the intra-cluster reactions of NO+(H2O)n clusters, following ionization of the parent neutral cluster of NO(H2O)n, were investigated using the direct ab initio molecular dynamics method. When n = 4, [NO+(H2O)4]ver [vertical ionization state of NO(H2O)n] yielded HONO and hydrated H3O+ after the intra-cluster reaction, and the reaction time was calculated to be 150 fs. The reaction is expressed as [NO+(H2O)n]ver → HONO + H3O+(H2O)n-2 (reactive) (n > 3). Larger clusters of [NO+(H2O)n]ver (n = 5-8) also yield HONO. In contrast, in smaller clusters (n = 1-3), only solvent re-orientation around NO+ occurred after the ionization: [NO+(H2O)n]ver → NO+(H2O)n (solvent re-orientation) (n = 1-3). The hydration energy of H3O+, which depends on the cluster size (n), plays an important role in promoting the formation of HONO. The reaction mechanism is discussed based on theoretical results.
Collapse
Affiliation(s)
- Hiroto Tachikawa
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Kita-ku, Sapporo 060-8628, Japan
| |
Collapse
|
2
|
Tachikawa H, Izumi Y, Iyama T, Abe S, Watanabe I. Aluminum-Doping Effects on the Electronic States of Graphene Nanoflake: Diffusion and Hydrogen Storage Mechanism. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2046. [PMID: 37513057 PMCID: PMC10384847 DOI: 10.3390/nano13142046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/04/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023]
Abstract
Graphene nanoflakes are widely utilized as high-performance molecular devices due to their chemical stability and light weight. In the present study, the interaction of aluminum species with graphene nanoflake (denoted as GR-Al) has been investigated using the density functional theory (DFT) method to elucidate the doping effects of Al metal on the electronic states of GR. The mechanisms of the diffusion of Al on GR surface and the hydrogen storage of GR-Al were also investigated in detail. The neutral, mono-, di-, and trivalent Al ions (expressed as Al, Al+, Al2+, and Al3+, respectively) were examined as the Al species. The DFT calculations showed that the charge transfer interaction between Al and GR plays an important role in the binding of Al species to GR. The diffusion path of Al on GR surface was determined: the barrier heights of Al diffusion were calculated to be 2.1-2.8 kcal mol-1, which are lower than Li+ on GR (7.2 kcal/mol). The possibility of using GR-Al for hydrogen storage was also discussed on the basis of the theoretical results.
Collapse
Affiliation(s)
- Hiroto Tachikawa
- Department of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Yoshiki Izumi
- Department of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Tetsuji Iyama
- Department of Applied Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Shigeaki Abe
- Department of Dental and Biomedical Materials Science, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8102, Japan
| | - Ikuya Watanabe
- Department of Dental and Biomedical Materials Science, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8102, Japan
| |
Collapse
|
3
|
Li R, Han X, Liu Q, Qian A, Zhu F, Hu J, Fan J, Shen H, Liu J, Pu X, Xu H, Mu B. Enhancing Hydrogen Adsorption Capacity of Metal Organic Frameworks M( BDC)TED 0.5 through Constructing a Bimetallic Structure. ACS OMEGA 2022; 7:20081-20091. [PMID: 35721999 PMCID: PMC9201887 DOI: 10.1021/acsomega.2c01914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Metal organic frameworks (MOFs) have promising application prospects in the field of hydrogen storage. However, the successful application of MOFs in the field is still limited by their hydrogen storage capacity. Herein, a series of M x M1-x (BDC)TED0.5 (M = Zn, Cu, Co, or Ni) with a bimetallic structure was constructed by introducing two metal ions in the synthesis process. The results of X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma showed that the bimetallic structure with different content ratios can be stably constructed by a hydrothermal method. Among them, the Cu-based bimetal MOFs Cu0.625Ni0.375(BDC)TED0.5 exhibited the best hydrogen storage capacity of 2.04 wt% at 77 K and 1 bar, which was 22% higher than that of monometallic Ni(BDC)TED0.5. The enhanced hydrogen storage capacity can be attributed to the improved specific surface area and micropore volume of bimetal MOFs by introducing an appropriate amount of bimetallic atoms.
Collapse
Affiliation(s)
- Renjie Li
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xin Han
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Qiaona Liu
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - An Qian
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Feifei Zhu
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Jiawen Hu
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Jun Fan
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Haitao Shen
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Jichang Liu
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
- Key
Laboratory for Green Processing of Chemical Engineering of Xinjiang
Bingtuan, School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003, China
| | - Xin Pu
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Haitao Xu
- State
Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Bin Mu
- School
for Engineering of Matter, Transport, and Energy, Arizona State University, 501 East Tyler Mall, Tempe, Arizona 85287, United
States
| |
Collapse
|
4
|
Tachikawa H, Lund A. Structures and electronic states of trimer radical cations of coronene: DFT-ESR simulation study. Phys Chem Chem Phys 2022; 24:10318-10324. [PMID: 35437545 DOI: 10.1039/d1cp04638a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Coronene (C24H12), a charge transfer complex with low-cost and high-performance energy storage, has recently attracted attention as a model molecule of graphene nano-flakes (GNFs). The stacking structures of the trimer radical cation correlate strongly with the conduction states of the GNFs. In the present paper, the structures and electronic states of the monomer, dimer and trimer radical cations of coronene were investigated by means of density functional theory calculations. In particular, the proton hyperfine coupling constants of these species were determined. The radical cation of coronene+ (monomer) showed two structures corresponding to the 2Au and 2B3u states due to the Jahn-Teller effect. The 2Au state was more stable than the 2B3u state, although the energy difference between the two states was only 0.03 kcal mol-1. The dimer and trimer radical cations took stacking structures distorted from a full overlap structure. The intermolecular distances of the molecular planes were 3.602 Å (dimer) and 3.564 and 3.600 Å (trimer). The binding energies of the dimer and trimer were calculated to be 8.7 and 13.3 kcal mol-1, respectively. The spin density was equivalently distributed on both coronene planes in the dimer cation. In contrast, the central plane in the trimer cation had a larger spin density, ρ = 0.72, than the upper and lower planes, both with ρ = 0.14. The proton hyperfine coupling constants calculated from these structures and the electronic states of the monomer, dimer, and trimer radical cations of coronene were in excellent agreement with previous ESR spectra of coronene radical cations. The structures and electronic states of (coronene)n+ (n = 1-3) were discussed on the basis of the theoretical results.
Collapse
Affiliation(s)
- Hiroto Tachikawa
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| | - Anders Lund
- Department of Physics, Chemistry and Biology, Linköping University, S-581 83 Linköping, Sweden.
| |
Collapse
|
5
|
Tachikawa H. Reaction mechanism of an intracluster S N2 reaction induced by electron capture. Phys Chem Chem Phys 2022; 24:3941-3950. [PMID: 35098286 DOI: 10.1039/d1cp04697g] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bimolecular nucleophilic substitution (SN2) reactions have been widely investigated from both experimental and theoretical points of view because they represent one of the simplest organic reactions. Most studies on SN2 reactions have been focused on bimolecular collision. In contrast, information on intracluster SN2 reactions is limited. In this study, an intracluster SN2 reaction of NF3-CH3Cl triggered by electron attachment was investigated using a direct ab initio molecular dynamics (AIMD) method. In the structure of NF3-CH3Cl, the N-F bond in NF3 is oriented collinearly toward the carbon atom of CH3Cl. After electron capture by NF3-CH3Cl, the F- ion that is generated from the (NF3)- moiety collides with the carbon atom of CH3Cl. The intracluster SN2 reaction occurs as follows: (NF3-CH3Cl)- (electron capture state) → NF2-(F-)-CH3Cl (pre-reaction complex) → transition state (TS) → NF2-CH3F-Cl- (post-reaction complex) → NF2 + CH3F + Cl- (product state). The reaction energy is efficiently transferred to the translational mode of Cl-, and the Cl- ion with a high translational energy is then removed from the system. This energy is significantly larger than that of Cl- formed in the bimolecular SN2 reaction (F- + CH3Cl). The reaction mechanism is discussed based on the theoretical results.
Collapse
Affiliation(s)
- Hiroto Tachikawa
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
| |
Collapse
|
6
|
Hydrogen Storage Mechanism in Sodium-Based Graphene Nanoflakes: A Density Functional Theory Study. HYDROGEN 2022. [DOI: 10.3390/hydrogen3010003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Carbon materials, such as graphene nanoflakes, carbon nanotubes, and fullerene, can be widely used to store hydrogen, and doping these materials with lithium (Li) generally increases their H2-storage densities. Unfortunately, Li is expensive; therefore, alternative metals are required to realize a hydrogen-based society. Sodium (Na) is an inexpensive element with chemical properties that are similar to those of lithium. In this study, we used density functional theory to systematically investigate how hydrogen molecules interact with Na-doped graphene nanoflakes. A graphene nanoflake (GR) was modeled by a large polycyclic aromatic hydrocarbon composed of 37 benzene rings, with GR-Na-(H2)n and GR-Na+-(H2)n (n = 0–12) clusters used as hydrogen storage systems. Data obtained for the Na system were compared with those of the Li system. The single-H2 GR-Li and GR-Na systems (n = 1) exhibited binding energies (per H2 molecule) of 3.83 and 2.72 kcal/mol, respectively, revealing that the Li system has a high hydrogen-storage ability. This relationship is reversed from n = 4 onwards; the Na systems exhibited larger or similar binding energies for n = 4–12 than the Li-systems. The present study strongly suggests that Na can be used as an alternative metal to Li in H2-storage applications. The H2-storage mechanism in the Na system is also discussed based on the calculated results.
Collapse
|
7
|
Abstract
The reaction of NO+ with water molecules plays a crucial role in the D-region of the atmosphere because the reaction provides nitrous acid (HONO) and protonated water species (H3O+). In this study, the reaction of NO+ with water clusters, NO+ + (H2O)n (n = 1-7), was investigated by means of the direct ab initio molecular dynamics method to elucidate the reaction mechanism of NO+ in the atmosphere from a theoretical viewpoint. At n = 1 and 2, the reaction of NO+ with (H2O)n led to the formation of a complex: NO+ + (H2O)n → NO+(H2O)n (n = 1 and 2). At n = 3, the formation channel of HONO was open, and HONO was formed according to NO+ + (H2O)n → HONO---H+(H2O)n-1 (n = 3), through which H3O+ was also formed as H+(H2O)2. However, the HONO formation efficiency was significantly low for n = 3. In large clusters with n = 4-7, the HONO formation channel became the main channel, and the dissociation of HONO from the HONO--H+(H2O)n-1 complex occurred in part: NO+ + (H2O)n → HONO---H+(H2O)n-1 → HONO + H+(H2O)n-1. The energetics and reaction mechanism were discussed on the basis of theoretical results.
Collapse
Affiliation(s)
- Hiroto Tachikawa
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan
| |
Collapse
|