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Materials that can undergo structural or phase transformations have attracted considerable attention as functional materials in many fields for electric, magnetic, optical, adsorption, separation, or catalysis applications. Outstanding examples of structure-switchable or phase-changeable metal complexes with fluorinated anions have been reported. This review focuses on recent advances in the literature on coordination polymers and metal complexes with fluorinated anions. For representative examples, the physical/chemical properties (crystal-to-crystal, crystal-to-plastic crystal, and crystal-to-liquid phase changes, guest accommodation/removal, magnetic properties, etc.) induced by external stimuli such as temperature/pressure changes are discussed, with comparisons to the properties of coordination polymers/metal complexes with nonfluorinated anions. In addition, ELM-11 (ELM = elastic layer-structured metal–organic framework) with fluorinated BF4 anions, which is the first discovered structure-switchable, crystalline coordination polymer with fluorinated anions showing gate adsorption/desorption properties, is examined. The coordination states of fluorinated anions in coordination polymers/metal complexes, together with the adsorption/separation properties, are also considered. These insights can aid in understanding the roles and features of fluorinated anions in such materials.

Iodine is one of the essential elements for human nutrition. Iodine measurement in biological samples is carried out almost exclusively by one of two methods: One is a kinetic spectrophotometric method called the Sandell-Kolthoff reaction based on the reduction of yellow Ce(IV) by As(III) to colorless Ce(III), which is normally very slow. Consequently, other methods, for example, inductively coupled plasma mass spectrometry (ICP-MS), are used. This chapter presents the detailed descriptions for these analytical methods. Ion-selective electrodes (ISEs) are commercially available for iodide and have been applied for the determination of iodide. Local structural information such as interatomic distances, coordination numbers, and Debye-Waller parameters, which are complementary to the vibration frequencies obtained by infrared (IR) and Raman spectroscopy, can be obtained by analyzing the extended X-ray absorption fine structure (EXAFS) part of the X-ray absorption spectra.

Water vapor adsorption on porous carbons has been actively studied because of its importance in various applications and basic science. However, the unique behavior and structure of water in carbon nanospaces have still been remained unclear. Carbon nanotubes inherently have rather restricted one-dimensional nanospaces and thus, force the adsorbed water to be aligned in them. The structure of water adsorbed in those nanospaces is ice-like even at ambient temperature. In this paper, we show the water structures in two-different single wall carbon nanotubes (CNTs) with average CNT diameters of 1.1 (narrow) and 2.5 (wide) nm at 260-300 K, which were evaluated by using <i>in situ</i> synchrotron X-ray diffraction (XRD). The water structures in the both CNTs were nano-ice-like forms at 300 K rather than a liquid-like. The ice-like structure in the wide CNTs was developed with decreasing temperature, although even at 260 K, sharp ice peaks were not observed in the XRD pattern. On the other hand, in the narrow CNTs, the water structure was gradually transformed from an ice-like form to a liquid-like form with decreasing temperature to 260 K. The structure transformation of solid-to-liquid with decreasing temperature is due to the fact that the highly restricted nanospaces obstruct the formation of ice-like clusters and/or hydrogen bonds. The anomalous structure transformation in both CNTs could be a clue to reveal one-dimensional water behavior in CNTs.

Confinement of KI nanocrystals in nanoscale pores of single wall carbon nanohorn (SWCNH) and activated carbon fiber (ACF) below 0.1 MPa induces the formation of high pressure phase solid, although compression under 1.9 GP is necessary for formation of the high pressure phase. Also formation of sulfur-atomic chain crystal having metallic nature is found in the single wall carbon nanotube (SWCNT) and double wall carbon nanotube (DWCNT) below 0.1 MPa, although mettalic sulfur needs compression by more than 90 Gpa in the bulk phase. This remarkably strong compression effect of carbon nanospaces was applied to organic synthesis. Organic synthetic reaction, which occurs only above high pressure of 1GPa without nanopore systems, efficiently progresses in a glass flask under an atmospheric pressure.

High-density CH4 storage using adsorption techniques is an important issue in the use of CH4 as a clean energy source. The CH4 adsorption mechanism has to be understood to enable innovative improvements in CH4 adsorption storage. Here, we describe the adsorption mechanism, based on CH4 structure, and stabilities in the internal and external nanopores of single-walled carbon nanohorns, which have wide and narrow diameters, respectively. The adsorption of larger amounts of CH4 in the narrow nanopores at pressures lower than 3 MPa was the result of strong adsorption potential fields; in contrast, the wider nanopores achieve higher-density adsorption above 3 MPa, despite the relatively weak adsorption potential fields. In the wider nanopores, CH4 molecules were stabilized by trimer formation. Formation of CH4 clusters therefore compensates for the weak potential fields in the wider nanopores and enables high-density adsorption and adsorption of large amounts of CH4.

いわゆる錯体と同様，遷移金属イオン，有機配位子および陰イオンからなる配位高分子の結晶は，水素結合や芳香族環の間の比較的弱い相互作用の存在により，ガス分子の圧力変化に従って協同的にクラスター形成反応を進行させ，構造変化をともなうガス分子の取り込みや放出を示すことが明らかになっている。この現象は，金属周りの配位構造や結晶の集合状態が変化するため色調も変化し，見た目にも変化を確認できるものであり，層状結晶の層間隔の拡張・収縮にともなうので，ゲートが開いたり閉じたりすることに例えて，ゲート現象と呼んでいる。金属イオン，対陰イオンの組み合わせにより，多様なガス分子に対して，複雑な応答を示すことがわかってきている。

The adsorptivities of supercritical CH4 and H-2 of the external and internal tube walls of single wall carbon nanotube (SWCNT) were determined. The internal tube wall of the negative curvature showed the higher adsorptivities for supercritical CH4 and H-2 than the external tube wall of the positive curvature due to their interaction potential difference. Fine SWCNT bundles were prepared by the capillary force-aided drying treatment using toluene or methanol in order to produce the interstitial pore spaces having the strongest interaction potential for CH4 or H-2; the bundled SWCNT showed the highest adsorptivity for supercritical CH4 and H-2. It was clearly shown that these nanostructures of SWCNTs are crucial for supercritical gas adsorptivity.

Intensive change in electronic structure of single wall carbon nanotube (SWCNT) bundles is observed, arising from intercalation of naphthalene into the interstitial spaces of the bundles with adsorption from solution. Ultraviolet photoelectron spectroscopy shows a clear increase in the density of states reaching the Fermi level, explicitly indicating pseudometallization of SWCNT by this simple and scalable intercalation method. On the other hand if a nonvolatile pentacene is deposited on the external bundle surface in vacuum, SWCNT shows no similar change in the density of states. © 2010 The American Physical Society.

Effect of pore width (w) and equilibration time on hysteresis of water adsorption isotherm was studied at 303-323 K using hydrophobic activated carbon fiber (ACF). The adsorption isotherm of ACF of w = 1.1 nm has a wide hysteresis loop; the longer the equilibration time from 5 min to 16 h, the narrower the loop width due to a lower pressure shift of the adsorption branch. This fact indicates that adsorption branch stems from a metastable adsorption. (C) 2009 Elsevier Ltd. All rights reserved.

Nanoporous composites of carbon nanosheets and single or mixed TiO2 and SiO2 were synthesized from graphite oxide (GO) precursor by a mechanochemical intercalation (MCI) method and their structural and adsorption/photocatalytic properties examined. It was found that a mixed Ti and Si organic phase behaves differently from a single phase in the MCI process, with linkages of SiO2 and TiO2 forming between the carbon layers, leading to an intercalation structure with improved surface hydrophilicity and a composite with enhanced microporosity and a reduced total amount of oxides. Although structural regularity of intercalated GO becomes poorer by applying Ti species in the MCI method, carbon-mixed oxide composites with an appropriate pore structure and sufficient Ti content exhibit a synergy effect of adsorption concentration and photocatalysis toward organic molecules. (C) 2008 Elsevier Inc. All rights reserved.

Activated carbon fibres with extremely high surface areas (ACFs) were prepared by CO2 re-activation using pitch-based ACFs having an original surface area of 1730 m(2)/g. The highest surface area of the re-activated ACFs was 2930 m(2)/g as determined from an alpha(S)-plot analysis of the nitrogen adsorption isotherm measured at 77 K. The ACF with the highest surface area showed excellent adsorptivity towards supercritical CH4 and H-2. The amounts of CH4 and H-2 adsorbed were enhanced by 52% and 30%, respectively, as a result of re-activation.

Nanoporous metals and nanometals need stabilizers which prevent them from sintering or oxidizing. Nanoporous Pt, Ni, or Pd, which were prepared by using silica nanoparticles or PVA films as templates, can be stabilized by a trace or small amount of carbons, which coat surfaces of the metals. Also, single wall carbon nanohorn can be a good stabilizer and catalyst support. The properties of such nanocarbons are reviewed for stabilization of nanometals.

Single wall carbon nanotube (SWCNT), which has bundle structure and entangled structure, was untangled and cut by sonication in hydrogen peroxide (H(2)O(2)) solution. The untangled state of SWCNT was examined by SEM, TEM, Raman spectroscopy and N(2) adsorption. It was confirmed that the surface area of sonicated nanotubes strongly depended on the sonication time. The BET specific surface area (SSA) of nanotubes sonicated for 3 h was maximum. The SSA decreased at 6 h or more of sonication time. These results indicated that the bundle structure was untangled and the cap of SWCNT was opened. Thus, N(2) molecules can access the most efficiently inside of the SWCNT sonicated for 3 h. On the contrary, the sonication treatment for 6 h or more decomposed the nanotubes to produce amorphous carbon, evidenced by TEM and SEM observation; the amorphous carbon blocked the open pore sites such as the internal pore spaces and interstitial pores.

We showed water adsorption isotherms at 303 K on water-resistant three-dimensional (3-D) pillared-layer metal organic frameworks (MOFs) with I -D semi -rectangular pores, of which size depends on the length of ligand. The shapes of all three adsorption isotherms are type I by IUPAC classification showing strong water-MOFs interaction. The adsorbed amount of water molecules on the hydrophilic site of carboxylic group in 2-D sheets coincided with the crystal water amount. The adsorption on the hydrophilic sites occurs at similar relative pressure even if the used ligand is different. (c) 2007 Elsevier Inc. All rights reserved.

Nanoporous carbon-silica composites were synthesized from graphite oxide (GO) precursor by a mechanochemical intercalation (MCI) method at different conditions, and their structural property, thermal decomposition behaviors, and adsorption characteristics were examined. MCI method yields regular tetraethoxysilane (TEOS)-intercalated GO layer structures with controllable silicon content depending on the TEOS addition. Adsorption behaviors of water and hexane indicate the amphiphilic properties of the composites. The detailed porosities of the composites and their changes upon water adsorption were analyzed on the basis of alpha(s)-plot method of N-2 adsorption isotherms using a weight-averaged standard data from non-porous silica and non-porous carbon, which plausibly divides microporosity and mesoporosity. (c) 2007 Elsevier Inc. All rights reserved.

Interfacial importance and nanopore structures of single wall nanocarbons such as single wall carbon nanotube (SWCNT) and single wall carbon nanohorn (SWCNH) are described in terms of intermolecular interaction theory. The relationships between the nanopore structure and nanoconfinement effect for molecules and ions are shown using examples on supercritical H2 adsorption on SWCNT, quantum molecular sieving effect of SWCNT for H2 and D2 below 77 K, water structure and hydration structure of Rb, Cs, and Sr ions in nanopores of activated carbon fiber and SWCNH, and capacitance storage of SWCNH. The SWCNT produced by laser ablation shows upward-curved adsorption isotherm of H2 at 77 K, suggesting the presence of the strong sites. The adsorption amount of D2 on this SWCNT at 77 K was clearly larger than that of H2 by about 20% at 77 K due to quantum effect. The hydration number around Cs and Sr ions in 1.1 nm slit pores of ACF reduced by more than 20 %. The capacitance depended on the opening of SWCNH and charging time for organic electrolyte (C2H 5)4NBF4 in propyrene carbonate. ©The Electrochemical Society.

One-dimensional metal-organic compounds with cis, trans symmetry-controlled counter anions were synthesized (cis compound {[Cu(azpy)(H2O)(2)(OTs)(2)]center dot 2H(2)O center dot(acetone)} (1) and trans compound {[Cu(H2O)(4)Cu(azpy)(2)(OTs)(2)(H2O)(2)]center dot 2(OTs)center dot 2H(2)O center dot 2EtOH} (2)). Only 2, having trans conformation, exhibited a complete structure-restoration effect with a mechanism involving layering of molecular "bricks" of water and solvent molecules.

A novel layered mesoporous carbon (LMC) material with structural peculiarity can be obtained by leaching silica components from the high temperature treatment products of degraded graphite layers and silica nanocomposites soft-chemically synthesized from graphite precursor. Nitrogen adsorption indicates that LMC exhibits a high mesopore specific surface area with only mesoporosity of narrow pore size distribution. Structural analysis shows a crystalline disordered but a unique wrinkled layered structure inside which ultrafine carbon microtextures with three to four carbon hexagonal layers, each of which has a perfect in-plane polyaromatic ring of 2.5-3.0 nm in length, stacking along c-axis are assembled together. Mesopores are assumed to be present in the large wrinkled layers and be house-of-card surrounded by several carbon hexagonal layers. LMC with a large specific surface area but lack of active oxygen-containing groups well resists to high temperature oxidation. (c) 2006 Elsevier Inc. All rights reserved.

A single-wall carbon nanohorn (SWNH) colloid was made to be magnetically responsive by anchoring magnetite nanoparticles prepared by the homogeneous mixing of FeCl2-FeCl3 and NaOH solutions. Transmission electron microscopy observation showed the high dispersion of magnetite particles of 2-9 nm on the surface of the SWNH colloid, coinciding with the broad X-ray diffraction peaks of the magnetites. The magnetization measurements showed that the magnetite nanoparticles-anchored SWNH (mag-SWNH) colloid has the hybrid property of ferrimagnetism and superparamagnetism. It was demonstrated that mag-SWNH colloid dispersed in water by sonication responded to an external magnetic field, gathering toward a magnet. N-2 adsorption experiments showed the high nanoporosity of mag-SWNHs and that magnetite nanoparticles were preferably anchored at "nanowindow" sites and the entrance sites of interstitial pores. This magnetically responsive SWNH colloid should contribute to the field of drug delivery.

An overview of the preparation and characterization of mesoporous zeolites and how the added mesoporosities are related to the synthesis and processing conditions is given. Mesopore-modified zeolites can be prepared via several routes. Different posttreatments of the synthesized zeolites are used: alkaline leaching or hydrothermal and other chemical treatments are the most frequently applied. These treatments provide zeolites with an inhomogeneous distribution of mesopores formed from defect domains. Novel dual templating methods using carbon materials have recently been developed. Variations in mesostructures from carbon templating and hydrothermal synthesis conditions of zeolites provide significant variations in the structural characteristics of the resulting mesoporous zeolites. In many commercial applications, mesopore-modified zeolites are receiving considerable attention. The large variety of potential and existing commercial applications is largely due to the novel framework compositions of the mesopore-modified zeolites.

Attempts to prepare macroporous silica particles and metal-compound-nanoparticle-embedded silica microspheres were carried out using reactions between silicon tetrachloride and ultrasonic generating microdroplets including metal (Na, K, Al, Ni Ti, Pt) compounds. Samples were collected by dry and wet processes. In the case of using nickel and aluminum compounds, acid-treated samples were also prepared. The obtained samples were characterized by scanning electron microscopy, X-ray fluorescence spectroscopy, powder X-ray diffractometry, mercury porosimetry, and the nitrogen adsorption method. The macroporous silica particles were prepared by removing the salt crystals, such as NaCl and KCl, formed in the silica frame. For acid-resistant metals, platinum- and titanium-compound nanoparticles are easily embedded in silica microspheres using these metal-compound solutions. For acid-soluble metals, aluminum- and nickel-compound-nanoparticle-embedded silicas were prepared by applying neutralization of the collection water. Micropores and mesopores were produced in wet-process samples. Acid treatment induced the increase of micropore volumes. (c) 2005 Elsevier Inc. All rights reserved.

N2 adsorption on Cu–organic crystals [Cu(bpy)2(BF4)2] (bpy = bipyridine) at 77 K begins suddenly at P/P 0 = 0.1. This unique adsorption is named gate adsorption. Gate adsorption is associated with the change of crystal structure from GCMC and dynamic GCMC simulations. An expansion of 10% opens internal pore spaces in the crystal, giving rise to gate adsorption. The complete filling of the internal spaces with N2 molecules induces an expansion of 30%. © 2006, Taylor & Francis Group, LLC.

ZSM-5 zeolites having SiO2/Al2O3 molar ratios of 23.8 and 200 were treated in 0.05 M NaOH solutions at 325 K. The pore structure changes were investigated by low temperature nitrogen and argon adsorption. The mesopores with broad mesopore size distributions were developed after alkaline treatment of ZSM-5 with a low SiO2/Al2O3 molar ratio 23.8. Alkaline treatment of ZSM-5 with a high SiO2/Al2O3 molar ratio 200 gave no mesopores from both nitrogen and argon adsorption measurements. Formation of defect-cluster associated pores in ZSM-5 zeolite upon alkaline post-treatment is discussed.

Oxidation of silyl enolates was found to be smoothly catalyzed by [Cu(bpy)(BF4)2(H2O)2(bpy)] n (bpy = 4,4′-bipyridine) under molecular oxygen, and provided the corresponding α-hydroxy carbonyl compounds in high yield. The insoluble organic-inorganic hybrid polymer was readily recovered by centrifugation after the completion of reaction, and the recovered catalyst could be reused. Copyright © 2005 The Chemical Society of Japan.

Recovery of the desorption activation energy distribution from the experimental temperature programmed desorption (TPD) spectra is among the most difficult problems of adsorption science. Since the heterogeneity effects strongly influence on transport, diffusion, and catalytic reaction time, the estimation of their magnitude is very important for practical purposes. Up to the present, several theories have been used for the interpretation of the TPD results. Almost all advanced theoretical approaches take into account the effect of surface disorder (heterogeneity in desorption activation energy); however, they ignore the numerical difficulties coming from the "ill-posed" character of the linear Fredholm integral equations appearing in the theoretical description of the TPD results. Thus, there is a growing interest in developing novel methods supported by powerful numerical algorithms taking this into account. In the current study we propose a new approach and consider the theoretical aspect as well as numerical problems appearing in the TPD analysis. Our modeling is based on the well-known and generally accepted "absolute rate theory," which has been used extensively for the interpretation of TPD results. We propose and verify (applying computer simulations) the new advanced numerical hybrid type algorithms taking into account the heterogeneity effects. They seem to be very promising in TPD spectra analysis. The stability of the proposed advanced numerical methods is confirmed by the computer simulation experiments, and the results are compared with those obtained from the condensation approximation (CA) method. (c) 2005 Elsevier Inc. All rights reserved.

Single-wall carbon nanohorn (SWNH), which is a tubular particle with a cone cap, was oxidized in an oxygen flow at various temperatures. N-2 adsorption at 77 K, thermogravinietry (TG), differential thermal analysis (DTA), transmission electron microscopy, and Raman spectroscopy measurements were carried out on the oxidized SWNHs. The specific surface area of the oxidized SWNHs can be controlled by oxidation temperature, giving the maximum value of 1420 m(2)/g. The pore size distribution by the BJH method and the comparison plot of the N2 adsorption isotherms of SWNH oxidized at different temperatures against that of as-grown SWNH revealed the minimum oxidation temperature for opening internal nanopores. TG-DTA analyses determined the components of as-grown SWNH: amorphous carbon 2.5 wt %, defective carbon at the cone part 15 wt %, tubular carbon 70 wt %, and graphitic carbon 12 wt %. These systematic analyses provided the exact internal nanopore volume of 0.49 mL/g for pure SWNH particles.

A new preparation method for porous silica particles was developed using activated silica sols which are called nano-silica solutions in this paper. Several kinds of organic and inorganic acids are employed to neutralize diluted sodium silicate solutions to form the nano-silica solutions: formic acid, acetic acid, propionic acid, oxalic acid, succinic acid, (DL)-malic acid, citric acid, and tricarballylic acid as carboxylic acids, and sulfuric acid and hydrochloric acid as inorganic acids. The effect of salts in the nano-silica solution is also studied. The products were investigated using a field emission scanning electron microscope, an X-ray diffractometer, the nitrogen adsorption technique, and a mercury porosimeter. Microporous silicas were produced when carboxylic acids were applied; the formation of micropores was influenced by the pH of the nano-silica solutions and molecular sizes of the carboxylic acids. Addition of a salt in a citric acid solution increased the mesopore volume. Macropores were formed when inorganic acids including salts were applied; the salt nanoparticles which were crystallized in silica spheres acted as templates. The anion types and salt concentrations in the nano-silica solutions affected the aggregation condition of silica nanoparticles, following the Schulze-Hardy rule.

The growth mechanism of water clusters in carbon nanopores is clearly elucidated by in situ small-angle X-ray scattering (SAXS) studies and grand canonical Monte Carlo (GCMC) simulations at 293-313 K. Water molecules are isolated from each other in hydrophobic nanopores below relative pressures (P/P-0) of 0.5. Water molecules associate with each other to form clusters of about 0.6 nm in size at P/P-0= 0.6, accompanied by a remarkable aggregation of these clusters. The complete filling of carbon nanopores finishes at about P/P-0=0.8. The correlation length analysis of SAXS profiles leads to the proposal of a growth mechanism for these water clusters and the presence of the critical cluster size of 0.6 nm leads to extremely stable clusters of water molecules in hydrophobic nanopores. Once a cluster of the critical size is formed in hydrophobic nanopores, the predominant water adsorption begins to fill carbon nanopores.

We measured adsorption and desorption isotherms of methane on [Cu(4, 4'-bipyridine)(2)(BF4)(2)] (LPC) at 258, 273, and 303 K. Adsorption proceeds almost vertically at a definite pressure, which is named gate pressure. The lower the measurement temperature, the smaller the gate pressure. The temperature dependence of the gate pressure is expressed by the Clapeyron-Clausius equation, giving a thermodynamic evidence on the clathrate formation between the Cu complex and methane.

The average interstitial nanopore structure of single-wall carbon nanohorn (SWNH) assemblies was determined using X-ray diffraction and grand canonical Monte Carlo (GCMC) simulation aided N-2 adsorption at 77 K. The interstitial nanopores of SWNH assemblies can be regarded as quasi one-dimensional pores due to the partial orientation of the SWNH particles; the average pore width of the interstitial pores is 0.6 run. Good agreement between the GCMC simulation of a structural model with one-dimensional interstitial nanopores and an experimental adsorption isotherm below P/P-0 = 10(-4) is evidence of the quasi one-dimensionality of the interstitial nanopores. A snapshot from the GCMC simulation showed one-dimensional growth of adsorbed N-2 molecules.

We have measured N-2 adsorption isotherms on single-wall carbon nanohorns (SWNHs) over the temperature range of 77-92K, and isosteric heat of adsorption, q(st), were determined. Adsorption measurements for SWNHs have been also done for for H-2 at 20 K, and for H-2 and D-2 at 77 K, respectively. We have performed grand canonical Monte Carlo (GCMC) simulations of N-2, H-2, and D-2 for single-wall carbon nanotube (SWNT) models to compare with the experimental data. Simulated N-2 adsorption isotherm on a SWNT bundle model is in reasonably good agreement with the experimental isotherm on the SWNH assembly over a wide range of pressures at 77 K; however, simulated q(st)-values for the SWNT bundle suggest that the SWNH particles are incompletely arranged in the SWNH assembly. Simulated endohedral isotherm of classical H-2 inside an isolated SWNT model at 20 K showed that a density of adsorbed H-2 in the internal space of the SWNH particle is quite smaller than that of classical H-2 because of large quantum effects. In simulating H-2 and D-2 adsorption isotherms on the model SWNT bundle at 77 K, GCMC simulations based on the Feynman-Hibbs (FH) effective potential were applied to introduce quantum effects to the statistical properties generated by the classical Lennard-Jones (LJ) potential. We found that an adsorption ratio of H-2 to D-2 on the SWNT bundle from the FH-GCMC simulations is less than 0.91 depending on adsorption pressure; this is because the potential field of the SWNT bundle for H-2 is relatively weaker than that for D-2 even at 77 K, due to the wide quantum spreading of a H-2 molecule.

H-2 and D-2 adsorption on single-wall carbon nanohorns (SWNHs) have been measured at 77 K, and the experimental data were compared with grand canonical Monte Carlo simulations for adsorption of these hydrogen isotopes on a model SWNH. Quantum effects were included in the simulations through the Feynman-Hibbs effective potential. The simulation predictions show good agreement with the experimental results and suggest that the hydrogen isotope adsorption at 77 K can be successfully explained with the use of the effective potential. According to the simulations, the hydrogen isotopes are preferentially adsorbed in the cone part of the SWNH with a strong potential field, and quantum effects cause the density of adsorbed H-2 inside the SWNH to be 8-26% smaller than that of D-2. The difference between H-2 and D-2 adsorption increases as pressure decreases because the quantum spreading of H-2, which is wider than that of D-2, is fairly effective at the narrow conical part of the SWNH model. These facts indicate that quantum effects on hydrogen adsorption depend on pore structures and are very important even at 77 K.