Regulating C2H2 and CO2 Storage and Separation through Pore

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Regulating C2H2 and CO2 Storage and Separation through Pore Environment Modification in a Microporous Ni-MOF Weidong Fan, Xia Wang, Xiuping Liu, Ben Xu, Xiurong Zhang, Wenjing Wang, Xiaokang Wang, Yutong Wang, Fangna Dai, Daqiang Yuan, and Daofeng Sun ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.8b04783 • Publication Date (Web): 27 Dec 2018 Downloaded from http://pubs.acs.org on December 31, 2018

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ACS Sustainable Chemistry & Engineering

Regulating C2H2 and CO2 Storage and Separation through Pore Environment Modification in a Microporous Ni-MOF Weidong Fan,† Xia Wang,† Xiuping Liu,† Ben Xu,*,† Xiurong Zhang,† Wenjing Wang,*,‡ Xiaokang Wang,† Yutong Wang,† Fangna Dai,† Daqiang Yuan,‡ and Daofeng Sun*,† †School

of Materials Science and Engineering, College of Science, China University of Petroleum (East China), Qingdao, Shandong 266580, China ‡State

Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China Corresponding Author *Email: [email protected]; [email protected]; [email protected] Supporting Information ABSTRACT: The storage and separation of C2H2 and CO2 require specific porous materials having surfaces onto which C2H2 or CO2 molecular can be selectively adsorbed. Through the modification of a multifunctional ligand with -F, -Cl, NH2, -CH3, -OCH3, and inorganic secondary building units (SBUs) with bipy-N ligands (dimethylamine, pyridine, 4aminopyridine,

and

isonicotinic

acid)

based

on

a

microporous Ni-MOF, the pore environment optimization is realized, achieving the enhancement of the adsorption and separation performances of C2H2 and CO2. The C2H2 uptakes vary from 178.4 to 130.1

cm3·g-1

and CO2 from 83.8 to 44.6

cm3·g-1 at 273 K and 1 atm. The 4-aminopyridine and dimethylamine modified UPC-110 has the highest C2H2/CO2 separation selectivity (5.1), further supported and explained

usually mixed with CO2 or hydrocarbons due to that it is mainly from the partial combustion of methane or cracking of hydrocarbons.6-8 However, C2H2 and CO2 have the similar kinetic diameters (3.3 Å) and boiling points (189.3 K for C2H2 and 194.7 K for CO2) making their separation a huge challenge. Traditional separation techniques are solvent extraction or cryogenic distillation, which are based on their different solvent polarities and vapor pressures, are environment and energy intensive. Furthermore, carbon dioxide (CO2) is a greenhouse gas. At present, developing novel CO2 capture/storage material is a promising methods to reduce the environmental crisis due to over emission of CO2.

9-13

Therefore, the storage of C2H2 and CO2 is of

significant importance for industrial applications, and

via Grand Canonical Monte Carlo (GCMC) simulation and

developing novel absorbent materials is urgently demanded.

breakthrough experiments. Our work not only provides new

Metal-organic frameworks (MOFs) are novel inorganic-

porous materials for efficient C2H2 and CO2 storage but also

organic hybrid materials presenting strong functionality,

contributes to the strategy on improving gas adsorption and

large porosity and specific surface areas, small crystal

separation

density, and adjustable pore sizes, which can be applied in

properties

through

pore

environment

modification.

diverse fields including gas storage and separation, proton

KEYWORDS: Metal-organic frameworks, Pore environment

conduction, catalysis, thin film devices, luminescence,

modification, Adsorption, Separation, Breakthrough

chemical sensing, and biomedical imaging.14-20 The easy-

INTRODUCTION

the possibilities of regulating the behaviours of gas

Acetylene (C2H2) is widely utilized in the petrochemical and electronic industry as raw materials for varies products or as energy source for acetylene fuel cells.1-4 However, the storage and transportation of C2H2 is dangerous due to its extreme explosive nature at room temperature under pressures over 2 atm.5 Nevertheless, the produced C2H2 are

adjustable pore sizes and functionalized pore surfaces enable adsorption/separation in microporous MOFs. Therefore, the rational design and synthesis of functional MOFs enable the promising C2H2/CO2 storage and separation performances based on open metal locations and suitable pore spaces.21-23 The best performing example is a flexible MOF named UTSA-300a. The strong C-H···F interaction between

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Figure 1. Pore environment engineering with multiple ligands and metal sites, coordination environment of Ni3O(COO)6 SBU and coordination modes of TTCA3-. UTSA-300a and C2H2 triggers an open form structural, while

purification. The H3TTCA-R (H3TTCA = [1,1':3',1''-

it keeps closed for CO2, providing a high C2H2/CO2

terphenyl]-4,4'',5'-tricarboxylic acid, R = H, F, Cl, NH2,

selectivity.6

CH3, OCH3) was synthesized by iodination reaction,

In view of the current problems of MOFs materials in improving gas storage capacity and selective separation, we propose multifunctional ligands and SBUs-modified pore size and pore environmental control in a microporous NiMOF as one strategy to improve C2H2/CO2 storage and separation. In our work, UPC-105 with open metal sites was used as a matrix, through modifying the ligand and replacing the coordination water molecules on the SBU with bipy-N ligands, a series of MOFs (UPC-106, UPC-107, UPC108, UPC-109, UPC-110, UPC-111, and UPC-112) with controlled pore environments were successfully obtained, which

exhibit

enhanced

adsorption

and

separation

performances of C2H2 and CO2. The C2H2 and CO2 uptakes vary from 178.4 to 130.1 cm3·g-1 and 83.8 to 44.6 cm3·g-1, respectively, at 273 K and 1 atm. In particular, the 4aminopyridine and dimethylamine modified UPC-110 has the highest C2H2/CO2 separation selectivity (5.1), calculated by ideal solution adsorbed theory (IAST), which is also supported and explained by Grand Canonical Monte Carlo

Suzuki coupling reaction and then acidified with dilute hydrochloric acid (Scheme S1-6).24 The

1H

NMR

spectrum was collected using a 400 MHz Varian INOVA spectrometer and was referenced to the residual solvent peak. Elemental analysis (C, H, N) were conducted on a PerkinElmer 240 elemental analyzer. PXRD patterns of UPC-105, UPC-106, UPC-107, UPC-108, UPC-109, UPC110, UPC-111, and UPC-112 were measured on an analytical X-Pert pro diffractometer with Cu Kα radiation (γ = 1.54184 Å). Thermogravimetric analysis (TGA) were performed on a Mettler Toledo TGA under N2 flow, and the temperature ranges was from 40 to 900 °C (at 10 °C min-1). Fourier Transformed Infrared (IR) spectra were collected in the range of 4000-400 cm-1 using a Nicolet 330 FTIR spectrometer with KBr pellets. Synthesis of Compounds. Synthesis of UPC-105: H3TTCA (38.0 mg, 0.1049 mmol) and Ni(NO3)2·6H2O (50.0 mg, 0.1724 mmol) were dissolved in a mixed solvent of DEF (5 mL), MeOH (0.5 mL), and H2O (0.2 mL) in a 10 mL vial. After

(GCMC) simulation and breakthrough experiments.

slowly heated to 150 °C from room temperature in 5 hours,

EXPERIMENTAL SECTION

mixture was slowly cooled to 30 °C in 10 hours, and the

Materials and Methods. All chemical reagents were

the mixture was kept at 150 °C for 6 days. Subsequently, the crystals were collected with 85.0% yield based on H3TTCA.

commercially available and were used without further

2


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Figure 2. The change in the accessible diameter of the cages when dimethylamine, pyridine, 4-aminopyridine and isonicotinic acid are used to modify Ni3O(COO)6 SBU. PXRD was employed to examine the phase purity of the obtained crystals.

Synthesis of UPC-112: UPC-112 was prepared in the similar route of UPC-109 except that H3TTCA-Cl was used

Synthesis of UPC-106: UPC-106 was prepared in the

instead of H3TTCA. Yield: 32.0% (based on H3TTCA).

similar route of UPC-105 preparation except that H3TTCA-F

X-ray Crystallography. The crystallographic data of

was used instead of H3TTCA. Yield: 56.4% (based on

UPC-105, UPC-106, UPC-107, UPC-108, UPC-109, UPC-

H3TTCA-F).

110, UPC-111, and UPC-112 were obtained using

Synthesis of UPC-107: UPC-107 was prepared in similar route of UPC-105 except that a mixed solvent of DMA (5 mL), MeOH (0.5 mL), and H2O (0.2 mL) was used instead of DEF (5 mL), MeOH (0.5 mL), and H2O (0.2 mL). Yield: 84.0% (based on H3TTCA). Synthesis of UPC-108: UPC-108 was prepared in the similar route of UPC-107 except that H3TTCA-F was used instead of H3TTCA. Yield: 56.4% (based on H3TTCA-F). Synthesis of UPC-109: UPC-109 was prepared in the similar route of UPC-107 except that extra pyridine was used (31.0 mg, 0.3924 mmol). Yield: 82.5% (based on H3TTCA). Synthesis of UPC-110: UPC-110 was prepared in the similar route of UPC-107 except that extra 4-aminopyridine (31.0 mg, 0.3298 mmol) was used. Yield: 65.0% (based on H3TTCA).

The crystal with the appropriate size and quality is placed on the loop of the carrier platform. The Cu Kα ray Source (λ = 1.54184 Å) monochromated with a graphite monochromator was used as a diffraction source, and the diffraction point data of the crystal to be measured was collected by w scanning. Structural analysis was performed by the Superflip method through the Olex 2 software package (Version 1.2.10), and structural refinement was performed by the ShelXL method. All non-hydrogen

atom

coordinates

and

anisotropic

thermal parameters are corrected by F2 using the full matrix least squares method; hydrogen atoms are generated symmetrically by audit (C-H 0.96 Å). Using the SQUEEZE routine of PLATON to remove all solvent molecules from structures. CCDC 1862735-1862742

Synthesis of UPC-111: UPC-111 was prepared in the similar route of UPC-107 except that extra isonicotinic acid (31.0 mg, 0.2520 mmol) was used. Yield: 49.0% (based on H3TTCA).

Agilent SuperNova single crystal diffraction system.

contains the supplementary crystallographic data for this paper. Gas

sorption

measurements.

Gas

adsorption–

desorption measurements of N2, C2H2, and CO2 on UPC105, UPC-106, UPC-107, UPC-108, UPC-109, UPC-110,

3



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UPC-111, and UPC-112 were performed on the

structure, UPC-108 was obtained, which realized the

Micromeritics ASAP 2020 surface area and pore size

multifunctional modification of pore environment in a MOF.

analyzer. The temperatures of 77 K, 273 K, and 298 K were maintained with a liquid nitrogen bath, an icewater bath, and a water bath, respectively.

The H3TTCA-R (R = F, Cl, NH2, CH3, OCH3) ligandmodified MOF will improve the affinity for gas molecules and increase the amount of gas adsorption. For the

Breakthrough Experiments. Breakthrough experiments

regulation of the pore size is limited, modifying SBU with

were completed employing a self-made equipment coupled

different size and functionality of bipy-N ligands can

with a mass spectrometer (Hiden QGA). Activated powders

regulate the pore environment and the pore size to achieve

of UPC-110 (1500 mg) were filled in a stainless steel column

gas separation. Dimethylamine (neutral, 0.7874 Å × 2.4136 Å,

(diameter in 0.635 cm and length in 7 cm) as the adsorbent

atom to atom distance), pyridine (neutral, 2.76 Å × 2.35 Å), 4-

bed, which was kept at 80 °C for 12 h with the He flow (2 ±

aminopyridine (alkaline, 4.15 Å × 2.38 Å) and isonicotinic

0.5 cm3 min-1 at 298 K and 2 atm) for activation. Subsequently,

acid (acidic, 4.91 Å × 2.35 Å) were used to modify SBU. Due

a C2H2/CO2 mixed gas (50/50) was introduced to the column

to the acid-base effect and size effect of different substituents,

(2 ± 0.5 cm3 min-1 at 298 K and 2 atm).

three dimethylamine and three pyridine molecules replaced the coordination water molecules in the SBU in UPC-107 and

RESULTS AND DISCUSSION

UPC-109, respectively, while two 4-aminopyridine and one

Crystal Structure. Green crystals of UPC-105 were

dimethylamine in UPC-110, and one isonicotinic acid and

collected after the solvothermal reaction of H3TTCA and

two dimethylamine in UPC-111. The small size of

Ni(NO3)2·6H2O in DEF/MeOH/H2O (V: V: V = 10: 1: 1) at 150

dimethylamine does not change the accessible diameter of

oC

diffraction

the cage, but the larger size of pyridine, 4-aminopyridine,

measurements indicate that UPC-105 has an isoreticular

and isonicotinic acid reduces the accessible diameter of the

analogue of previously reported MOF (Fe-MOF and In-

smaller cage (8.0 Å, 6.4 Å, and 10 Å) and separates the larger

MOF).25,26 It is noteworthy that there are two different hollow

cage into four smaller cages (9.0 Å and 8.4 Å for UPC-109, 5.8

cages in UPC-105 as illustrated in Fig. S8. The smaller cage

Å and 8.4 Å for UPC-110, 4.4 Å and 8.4 Å for UPC-111) (Fig.

has a 10 Å accessible diameter and is constructed of six metal

2). It has been demonstrated that both the open metal sites

clusters connected by ligands, and the larger cages with the

and suitable pore distributions play critical roles in MOF-

19.0 Å accessible diameter is constructed of 12 metal clusters

based C2H2 storage.5 Therefore, the presence of cages with

connected by ligands. This pore structure provides an

different sizes in the structure is expected to improve the

effective platform for gas storage.

storage and selective ability of gases, such as C2H2 and CO2.

for

six

days.

Single-crystal

X-ray

To optimize the properties of MOF by introducing functional groups and modifying SBU, as well as to enrich the family of isoreticular MOFs, reactions with H3TTCA-R (R = F, Cl, NH2, CH3, OCH3) and bipy-N ligands (pyridine, 4aminopyridine

and

isonicotinic

acid,

dimethylamine

derived from the decomposition of DMA at high temperature) were carried out (Fig. 1). All the MOFs reported in this work were obtained by in-situ reaction instead of postsynthesis modification. Taking fluorinated ligand (H3TTCAF) and dimethylamine (NH(CH3)2) modified SBU as an example, UPC-106 could be obtained by substituting H3TTCA ligand in UPC-105 with H3TTCA-F ligand, and the modification of SBU with dimethylamine gave rise to UPC107. When the H3TTCA-F ligand and dimethylaminemodified SBU were simultaneously constructed in the same

Figure 3. N2 adsorption isotherms of UPC-105, UPC-106, UPC-107, UPC-108, UPC-109, UPC-110, UPC-111, and UPC112 at 77 K.

4


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Figure 4. UPC-105, UPC-106, UPC-107, UPC-108, UPC-109, UPC-110, UPC-111, and UPC-112: adsorption isotherms for (a) C2H2 (273 K), (b) C2H2 (298 K), (c) CO2 (273 K), and (d) CO2 (298 K). Qst values for C2H2 (e) and CO2 (f). IAST selectivities of C2H2/CO2 (50:50) mixture at 273 K (g) and 298 K (h). Chemical and Thermal Stability. The compounds UPC-

environment engineering for selective C2H2 uptake. UPC-105,

105, UPC-106, UPC-107, UPC-108, UPC-109, UPC-110, UPC-

UPC-106, UPC-107, UPC-108, UPC-109, UPC-110, UPC-111,

111, and UPC-112 possess similar chemical and thermal

and UPC-112 exhibit high C2H2 adsorptions of 177.5, 178.4,

stabilities. Significantly, PXRD patterns for various organic

167.3, 161.9, 133.6, 131.7, 135.5, and 130.1 cm3 g-1 at 273 K and

solvents (methanol, ethanol, acetone, dichloromethane,

1 atm, respectively, which are comparable to ZJU-26 (127 cm3

toluene) and water treated samples reveal that the crystalline

g-1),27 PCP-33 (179.2 cm3 g-1),28 ZJU-199a (169.5 cm3 g-1),29 and

integrity can be well retained for 24 h at room temperature.

ZJU-72a (179.7 cm3 g-1).30 When the temperature rises to 298

In addition, dimethylamine, pyridine, 4-aminopyridine, and

K, the adsorption amount of C2H2 is 118.7, 114.7, 98.4, 96.6,

isonicotinic acid modified UPC-107, UPC-108, UPC-109,

83.5, 73.4, 88.1, and 74.4 cm3 g-1, respectively, which are

UPC-110, UPC-111, and UPC-112 can be well retained even

comparable to ZJU-26 (84 cm3 g-1), UTSA-50a (90.6 cm3 g-1),31

in basic solutions (i.e., NaOH (pH 10)) for 12 h. The thermal

FJI-C4 (72.5 cm3 g-1),32 MOF-1 (100 cm3 g-1),33 ZnMOF-74 (122

stability was demonstrated through the temperature

cm3 g-1),2 and UTSA-34b (121 cm3 g-1).34

dependent PXRD and thermogravimetric analysis (TGA) measurements, and we suggest the crystals are stable below 200 °C.

However, they exhibit low CO2 adsorption under the same conditions with 83.8, 85.4, 74.6, 78.3, 62.5, 44.6, 69.5, and 65.0 cm3 g-1 at 273 K and 1 atm, respectively and with 53.0, 54.1,

Gas Sorption. To elucidate the permanent porosity of

46.1, 45.8, 39.5, 24.3, 42.1, and 40.9 cm3 g-1 at 298 K and 1 atm,

UPC-105, UPC-106, UPC-107, UPC-108, UPC-109, UPC-110,

respectively (Fig. 4a-d). Although UPC-105, UPC-106, UPC-

UPC-111, and UPC-112, gas adsorption isotherms were

107, and UPC-108 have similar porosity, the C2H2 and CO2

performed with the activated samples. All N2 (77 K) sorption

uptakes of UPC-105and UPC-106 are higher than UPC-107

isotherms are typical type I (Fig. 3). The order of uptakes

and UPC-108 because they have open metal sites in the

around 1 atm is UPC-105 (540.4 cm3 g-1) > UPC-106 (525.6 cm3

[Ni3O(COO)6] SBU and can form strong interactions with gas

g-1) > UPC-107 (484.6 cm3 g-1) > UPC-108 (478.0 cm3 g-1) >

molecules. The C2H2 and CO2 gas adsorption capacity of

UPC-111 (436.6

cm3

g-1)

> UPC-109 (416.2

cm3

g-1)

> UPC-112

UPC-109, UPC-110, UPC-111, and UPC-112 with lower

(408.3 cm3 g-1) > UPC-110 (367.8 cm3 g-1). This is consistent

porosity is further reduced. Especially for UPC-110, there

with the calculated porosities of the crystal structures (Table

was no significant change in the amount of adsorption of

S4). The BET and Langmuir surface areas calculated from the

C2H2 compared with UPC-109, UPC-111, and UPC-112, but

N2 sorption isotherm are listed in Table S4.

the amount of CO2 adsorption was significantly reduced. On

The C2H2 and CO2 sorption isotherms of UPC-105, UPC106, UPC-107, UPC-108, UPC-109, UPC-110, UPC-111, and

the one hand, the large cages in the structures are divided into small cages, resulting in a reduction in the size of the

UPC-112 were collected to evaluate the effectiveness of pore

5



opening of the cage. Furthermore, due to the different nature of the ligands modified on the SBU, the affinity with the gas

Page 6 of 10

the most preferred sites for C2H2 adsorption in UPC-110 mainly are the small cages, which might have strong overlapping potentials. In addition, there are more C2H2

Figure 6. Breakthrough curves obtained at 1 atm and 298 K Figure 5. (a) Snapshot of C2H2 and CO2 adsorption in UPC110 for C2H2/CO2 (50:50) mixture at 0.15 atm and 298 K. (b) and (c) Preferential C2H2 and CO2 adsorption sites and corresponding adsorption energies in UPC-110 obtained from DFT calculations. molecules are quite different, illustrating the necessary of pore environment engineering in regulating gas adsorption. Ideal adsorbed solution theory (IAST) was utilized for C2H2/CO2 selectivity calculation in this study (Fig. 4g,h).35 For C2H2/CO2 (50:50) gas at 298 K, the C2H2/CO2 selectivity of UPC-110 is 5.1, higher than UPC-105, UPC-106, UPC-107, UPC-108, UPC-109, UPC-111, and UPC-112 (Table S5). This is associated with that UPC-110 has a reduced porosity, a smaller open channel, and a Lewis base ligand modified channel surface. To understand the intensified C2H2 and CO2-MOF interactions in UPC-110, the adsorption isotherms at 273 K and 298 K were collected, and the adsorption enthalpy (Qst) was calculated using the Clausius–Clapeyron equation (Fig. 4e,f). The zero-coverage Qst value of C2H2 (24.6 kJ

mol-1)

in UPC-110 was found to be higher than that of

UPC-105, UPC-106, UPC-107, UPC-108, UPC-109, UPC-111, and UPC-112, but it is reverse for CO2, indicating the stronger interactions with C2H2 than CO2 in UPC-110. These results highlight the pore environment engineering in boosting the interactions with C2H2 by smaller opening size cages and amino-modified channel surface. GCMC Simulation and DFT calculation. To better understand the adsorption behaviours of C2H2/CO2 mixture gases in UPC-110 at the molecular level, snapshots of the structures with adsorbed gas molecules at 298 K and 0.15 atm were analysed by GCMC simulations.36,37 It was found that

by passing C2H2/CO2 (50:50) mixture through a column packed with UPC-110. molecules absorbed in the skeleton compared with CO2 molecules (molar ratio of C2H2 to CO2 is around 3:1), especially in amino-modified trap cavities, consistent with the ratio of uptakes C2H2/CO2 from experiments. DFT calculations were employed to further examine the improvement on gas adsorption by introducing the amino groups in UPC-110. The optimized structures, as well as the corresponding adsorption energies, are presented in Fig. 5a. The adsorption energies of one C2H2 molecule on the amino site or the dimethylamine site in UPC-110 are -33.90 or -31.07 kJ mol-1, higher than the adsorption energies of CO2 molecule (-15.27 kJ mol-1 on the amino site or -11.60 kJ mol-1 on the dimethylamine site), as shown in Fig. 5b,c and Fig. S19. We suggest that the electrical field quadrupole interactions between the amino or dimethylamine group and the C2H2 molecule enhance the polarization of C2H2, improving the adsorption capability. Breakthrough Experiments. For further investigating the C2H2/CO2 separation capabilities of UPC-110 for its practical applications, the breakthrough experiments were conducted. An equimolar gas mixture were introduced to the packed column filled with activated UPC-110 crystals in a total flow of 2 mL min-1 at the room temperature. As illustrated in Fig. 6, effective and applicable separation of C2H2/CO2 is achieved. Initially, only C2H2 pass through the column demonstrated by the mass chromatography at the outlet. After around 250 s, CO2 started to appear at the outlet due to that UPC-110 reached its saturation of CO2 adsorption. The breakthrough time of C2H2/CO2 is about 200 s, indicating that

6


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the effective C2H2 capture capacity of UPC-110 from the C2H2/CO2 mixture.

CONCLUSION In conclusion, through the modification of multifunctional ligands with -F, -Cl, -NH2, -CH3, -OCH3, and inorganic secondary building units (SBUs) with bipy-N ligands (dimethylamine, pyridine, 4-aminopyridine, and isonicotinic acid) based on a microporous Ni-MOF, optimization of the pore environment for enhanced C2H2/CO2 storage and separation performances is realized. Fluorine modified UPC106 has the highest C2H2 and CO2 gas storage performance with 178.4 and 85.4 cm3·g-1 at 273 K and 1 atm. The 4aminopyridine and dimethylamine modified UPC-110 has smaller opening size cage and porosity, but exhibits the highest C2H2/CO2 separation selectivity (5.1), calculated by ideal solution adsorbed theory (IAST), which is also proved by GCMC simulation and breakthrough experiment. The excellent C2H2 gas storage and C2H2/CO2 selective separation performance of UPC-110 is attributed to microporous and acid-base effects to increase the interaction between the MOF and C2H2 gas molecules. Our work presented here provides a synergistic strategy on improving gas storage and separation through modifying both organic ligands and SBUs to engineer the pore environment.

ASSOCIATED CONTENT Supporting Information Detailed characterization of UPC-105, UPC-106, UPC-107, UPC-108, UPC-109, UPC-110, UPC-111, and UPC-112. Crystal data, PXRD patterns, TGA curves, IR patterns, the C2H2 and CO2 sorption isotherms and C2H2/CO2 selectivity at 273 K and 298 K.

AUTHOR INFORMATION Corresponding Author *Email: [email protected] (B. Xu). *Email: [email protected] (W. Wang). *Email: [email protected] (D. Sun). ORCID Weidong Fan: 0000-0003-3933-6209 Ben Xu: 0000-0002-8166-1817 Wenjing Wang: 0000-0003-2139-1242 Yutong Wang: 0000-0001-8943-1832 Fangna Dai: 0000-0002-5300-5388 Daqiang Yuan: 0000-0003-4627-072X Daofeng Sun: 0000-0003-3184-1841 Notes The authors declare no competing financial interest.

ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China (NSFC, Grant No. 21571187), Taishan Scholar Foundation (ts201511019), and the Fundamental Research Funds for the Central Universities (18CX06003A, YCX2018071).

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For Table of Contents Use Only

Regulation of C2H2 and CO2 storage and separation is achieved through modifying both organic ligands and SBUs to engineer the pore environment in the microporous Ni-MOF.

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Regulating C2H2 and CO2 Storage and Separation through Pore

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