Xing-Zhe Guo - Academia.edu (original) (raw)

Papers by Xing-Zhe Guo

Research paper thumbnail of A stable paddle-wheel Co-MOF (FNU-2) for the efficient separation of light hydrocarbons

Microporous and Mesoporous Materials, 2024

The separation of methane from higher hydrocarbons (C 2-C 3) in natural gas processing is a cruci... more The separation of methane from higher hydrocarbons (C 2-C 3) in natural gas processing is a crucial and energyintensive operation. This work presents a comprehensive study on the separation of propane and ethane from methane using cobalt-based metal-organic frameworks (FNU-2), which exhibit exceptional stability and selectivity and preferential adsorption towards C 2-C 3 hydrocarbons. The selectivity values of C 2 H 6 /CH 4 and C 3 H 8 / CH 4 calculated by IAST are 43.9 and 638.9, respectively. According to theoretical calculations, the Van der Waals interactions of guest molecules play crucial roles in influencing the separation performance. Moreover, dynamic breakthrough experiments have revealed the promising potential of this adsorbent in industrial separations. These experiments indicate that the adsorbent is highly suitable for effectively separating and purifying natural gas. This study overall presents a novel and efficient adsorbent that can be employed to separate and purify natural gas in various industrial applications.

Research paper thumbnail of A stable ultramicroporous Cd(II)-MOF with accessible oxygen sites for efficient separation of light hydrocarbons with high methane production

Separation and Purification Technology, 2024

Metal-organic frameworks (MOFs) have garnered increasing attention for their effective separation... more Metal-organic frameworks (MOFs) have garnered increasing attention for their effective separation of light hydrocarbons owing to their prominent separation selectivity and energy-efficient adsorption process. Here, we constructed a robust stable ultramicroporous Cd(II)-MOF ([Cd 5 (NTA) 4 (H 2 O) 2 ] (Me 2 NH 2 +) 2 ⋅10H 2 O (1)) with abundant accessible oxygen sites and investigated its adsorption performance for recovering high-purity methane (CH 4) from natural gas (NG) including C 1 (CH 4)/C 2 (C 2 H 6)/C 3 (C 3 H 8) mixtures. At ambient conditions, the theoretical equilibrium separation selectivity of 1 for C 2 H 6 /CH 4 (v/v = 10/85) and C 3 H 8 /CH 4 (v/v = 5/85) were found to be 34.3 and 223.8, respectively. The CH 4 /C 2 H 6 /C 3 H 8 (v/v/v = 85/10/5) mixture breakthrough experiments for 1, conducted at 298 K, demonstrated effective separation performance with breakthrough times of up to 136 and 280 min⋅g − 1 for C 2 H 6 and C 3 H 8. Particularly, the CH 4 productivity (purity > 99.9 %) with 9.8 mmol⋅g − 1 ranked the third in reported literatures, lower to the reported maximum value of 13.28 mmol⋅g − 1 for Ni(TMBDC)(DABCO) 0.5. Furthermore, Grand Canonical Monte Carlo (GCMC) simulations and first-principles density functional theory (DFT) calculations revealed that the high uptake and selectivity for C 3 H 8 and C 2 H 6 can be attributed to the abundant oxygen sites present in the pores. The dynamic breakthrough experiments comprehensively demonstrated that the proposed MOF can be an effective potential adsorbent for the practical separation of CH 4 /C 2 H 6 /C 3 H 8 mixtures.

Research paper thumbnail of Syntheses, crystal structures, and properties of four coordination polymers based on mixed multi-N donor and polycarboxylate ligands

Journal of Solid State Chemistry, 2018

Four new coordination polymers [Ni2(HL1)2(L1)3(BTC)2]·6H2O (1), [Ni2(L1)3(HBTC)2]·4H2O (2), [Cd2(... more Four new coordination polymers [Ni2(HL1)2(L1)3(BTC)2]·6H2O (1), [Ni2(L1)3(HBTC)2]·4H2O (2), [Cd2(L2)(BTC)(H2O)3]·2H2O (3) and [Cd2(HL2)(BTCA)] (4) were synthesized by reactions of nickel(II)/ cadmium(II) salts with rigid ligands of 1,4-di(1H-imidazol-4-yl)benzene (L1), 1,3-di(1-imidazolyl)−5-(4H-tetrazol-5-yl)benzene (HL2) and polycarboxylic acids of 1,3,5-benzenetricarboxylic acid (H3BTC), 1,2,4,5-benzenetetracarboxylic acid (H4BTCA), respectively. The structures of the complexes were determined by single crystal X-ray diffraction analysis. The complex 1 is one-dimensional (1D) chain while 2 is a (4, 4)-connected two-dimensional (2D) layered structure with 2D → 2D parallel interpenetration. Complex 3 is a rare tetranodal (3,4)-connected three-dimensional (3D) CrVTiSc architecture with Point (Schläfli) symbol of (4·82)(4·84·10)(42·82·102)(83), and compound 4 has the 2D network with (4,4) topology based on the [Cd2(COO)4] SBUs. The weak interactions such as hydrogen bonds and π···π stacking contribute to stabilize crystal structure and extend the low-dimensional entities into high-dimensional frameworks. The UV–vis absorption spectra of 1 – 4 are discussed. Moreover, the photo luminescent properties of 3 and 4 and gas sorption property of 2 have been investigated.

Research paper thumbnail of Series of Cadmium(II) Coordination Polymers Based on a Versatile Multi-N-Donor Tecton or Mixed Carboxylate Ligands: Synthesis, Structure, and Selectively Sensing Property

ACS Omega, 2019

Five Cd(II) metal−organic frameworks (MOFs), [Cd(HL) 2 ] (1) , [ C d (H L) 2 (H 2 O) 2 ] (2) , [ ... more Five Cd(II) metal−organic frameworks (MOFs), [Cd(HL) 2 ] (1) , [ C d (H L) 2 (H 2 O) 2 ] (2) , [ C d 3 (H L) 2 (o b d a) 2 ] (3) , [Cd 2 (HL) 2 (ohmbda)(DMA)(H 2 O)] (4), and [Cd 2 (HL)(btc)(H 2 O) 2 ]· 3H 2 O (5), were prepared by reactions of Cd(NO 3) 2 ·4H 2 O with 1-(1H-imidazol-4-yl)-4-(4H-tetrazol-5-yl)benzene (H 2 L) or mixed carboxylate ancillary ligands of 1,2-benzenedicarboxylic acid (H 2 obda), 5-hydroxy-1,3-benzenedicarboxylic acid (H 2 ohmbda), and 1,3,5-benzenetricarboxylic acid (H 3 btc), respectively. Their structures have been characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy (IR), thermogravimetric analysis, and powder X-ray diffraction. Compounds 1 and 2 are supramolecular isomeric frameworks without consideration of the solvent molecules. Complex 1 exhibits a binodal (3, 5)-connected two-dimensional (2D) layer structure with the point (Schlafi) symbol of (5 2 · 6)(5 5 ·6 4 ·7), while complex 2 shows a 2D + 2D → 3D (three-dimensional) framework. Complex 3 is a (3, 5, 6)-connected tetranodal 3D net with the point (Schlafi) symbol of (4·8 2) 2 (4 5 ·6·8 4) 2 (4 5 ·6 5) 2 (4 8 ·6 6 ·8). Compound 4 is a (3, 3, 8)-connected trinodal 3D net with the point (Schlafi) symbol based on a binuclear [Cd 2 N 2 O] subunit, while 5 is a 2-nodal (3, 4)-connected 2D V 2 O 5-type network based on [Cd 2 N 2 (COO) 2 ] SBU. The studies of molecular sensing properties show that the luminescent MOFs can be employed as fluorescent sensors for the detection of Fe 3+ and nitro compounds. Compound 1 and 3 exhibit quenching responses for Fe 3+ in dimethylformamide solution with detection limits of 2.3 × 10 −6 and 8.6 × 10 −7 M, respectively. Meanwhile, compound 5 can sense 4-nitrophenol with a detection limit as low as 5.75 × 10 −7 M. ■ INTRODUCTION Metal−organic frameworks (MOFs) have aroused enormous interest in the field of crystal engineering because of their fascinating structures and potential applications such as gas storage and separation, 1−4 catalysis, 5,6 luminescence, and sensing. 7−12 Structurally, MOFs are infinite structures constructed from organic ligands and metal ions/clusters connected via coordination interactions. Therefore, the functionalities of MOFs are mainly attributable to the nature of the organic ligands and metal centers. 13,14 For example, the luminescent MOFs consisting of π-conjugated organic ligands and d 10 metal centers possess excellent luminescence emission properties and have received particular attention as chemical sensors for sensing nitroaromatic compounds and heavy-metal ions because of their high selectivity and sensitivity, quick response, and recoverability. 15−21 For example, the Wang group synthesized the complex {[Tb(L)1.5(H 2 O)]·DMA· 4H 2 O} n [N-heterocyclic dicarboxylic (2-pyrimidin-5-yl) ter-ephthalic acid (H 2 L) ligand], which can sense Fe 3+ as low as 7.13 × 10 −5 M. 22 Similarly, the crystalline product of [Cd(L 2)0.5(bipy)] shows highly selective sensing property for Fe 3+ ions. 23 As for the organic ligands, both of the nitrogen-rich ligands and carboxylic acids are most effective building units for the assembly of various MOFs because the multi-N and-O coordination atoms are easily apt to link with metal centers. 24−27 Particularly, the polyazaheteroaromatic ligands can exhibit flexible coordination modes to build diverse MOFs. 28−33 In our previous study, we have deliberately designated multi-N-donor ligands containing 1H-imidazol-4-yl groups to construct a series of porous frameworks exhibiting favorable gas adsorption properties because of the increasing interaction between the adsorbate and uncoordinated N binding sites as elaborately elucidated by Grand Canonical Monte Carlo simulation calculations. 34−36 Besides the polyazaheteroaromatic ligands, carboxylic acid ligands are another kind of building units for constructing MOFs due to

Research paper thumbnail of Effect of Synergistic Interplay between Surface Charge, Crystalline Defects, and Pore Volume of MIL-100(Fe) on Adsorption of Aqueous Organic Dyes

Ind. Eng. Chem. Res., 2020

We herein report that the morphology, size, and surface charge status of MIL-100(Fe) micro/nanopa... more We herein report that the morphology, size, and surface charge status of MIL-100(Fe) micro/nanoparticles can be tailored by adding a coordination modulator (HF or tetramethylammonium hydroxide) to the reaction system. Interestingly, the adsorption capacities of low-crystallinity MIL-100(Fe) and MIL-100(Fe)-TMA toward Congo red (CR) and acid chrome blue K (AC) were found to be significantly larger than that of the high-crystallinity MIL-100(Fe)-HF adsorbent, whereas there was little difference in the adsorption capacities of the three MIL-100(Fe) toward methyl orange (MO) and methylene blue (MB). The adsorption uptake of MIL-100-(Fe)-TMA toward the anionic dyes (CR, AC, and MO) was found to be highest, whereas the adsorption uptake of MIL-100(Fe) toward the cationic dye (MB) was the highest owing to different adsorption mechanisms. This adsorption behavior could be rationalized based on the morphological characteristics and crystal structure defects, zeta potential, and pore volume of MIL-100(Fe) and the adsorption characteristics and molecular structure of the dye. It was revealed that the adsorption performance of MIL-100(Fe) micro/nanoparticles is governed by the synergistic interplay between electrostatic, hydrophobic, and π–π stacking interactions, pore volume, crystal structure defects, and steric hindrance of the adsorbent.

Research paper thumbnail of A stable paddle-wheel Co-MOF (FNU-2) for the efficient separation of light hydrocarbons

Microporous and Mesoporous Materials, 2024

The separation of methane from higher hydrocarbons (C 2-C 3) in natural gas processing is a cruci... more The separation of methane from higher hydrocarbons (C 2-C 3) in natural gas processing is a crucial and energyintensive operation. This work presents a comprehensive study on the separation of propane and ethane from methane using cobalt-based metal-organic frameworks (FNU-2), which exhibit exceptional stability and selectivity and preferential adsorption towards C 2-C 3 hydrocarbons. The selectivity values of C 2 H 6 /CH 4 and C 3 H 8 / CH 4 calculated by IAST are 43.9 and 638.9, respectively. According to theoretical calculations, the Van der Waals interactions of guest molecules play crucial roles in influencing the separation performance. Moreover, dynamic breakthrough experiments have revealed the promising potential of this adsorbent in industrial separations. These experiments indicate that the adsorbent is highly suitable for effectively separating and purifying natural gas. This study overall presents a novel and efficient adsorbent that can be employed to separate and purify natural gas in various industrial applications.

Research paper thumbnail of A stable ultramicroporous Cd(II)-MOF with accessible oxygen sites for efficient separation of light hydrocarbons with high methane production

Separation and Purification Technology, 2024

Metal-organic frameworks (MOFs) have garnered increasing attention for their effective separation... more Metal-organic frameworks (MOFs) have garnered increasing attention for their effective separation of light hydrocarbons owing to their prominent separation selectivity and energy-efficient adsorption process. Here, we constructed a robust stable ultramicroporous Cd(II)-MOF ([Cd 5 (NTA) 4 (H 2 O) 2 ] (Me 2 NH 2 +) 2 ⋅10H 2 O (1)) with abundant accessible oxygen sites and investigated its adsorption performance for recovering high-purity methane (CH 4) from natural gas (NG) including C 1 (CH 4)/C 2 (C 2 H 6)/C 3 (C 3 H 8) mixtures. At ambient conditions, the theoretical equilibrium separation selectivity of 1 for C 2 H 6 /CH 4 (v/v = 10/85) and C 3 H 8 /CH 4 (v/v = 5/85) were found to be 34.3 and 223.8, respectively. The CH 4 /C 2 H 6 /C 3 H 8 (v/v/v = 85/10/5) mixture breakthrough experiments for 1, conducted at 298 K, demonstrated effective separation performance with breakthrough times of up to 136 and 280 min⋅g − 1 for C 2 H 6 and C 3 H 8. Particularly, the CH 4 productivity (purity > 99.9 %) with 9.8 mmol⋅g − 1 ranked the third in reported literatures, lower to the reported maximum value of 13.28 mmol⋅g − 1 for Ni(TMBDC)(DABCO) 0.5. Furthermore, Grand Canonical Monte Carlo (GCMC) simulations and first-principles density functional theory (DFT) calculations revealed that the high uptake and selectivity for C 3 H 8 and C 2 H 6 can be attributed to the abundant oxygen sites present in the pores. The dynamic breakthrough experiments comprehensively demonstrated that the proposed MOF can be an effective potential adsorbent for the practical separation of CH 4 /C 2 H 6 /C 3 H 8 mixtures.

Research paper thumbnail of Syntheses, crystal structures, and properties of four coordination polymers based on mixed multi-N donor and polycarboxylate ligands

Journal of Solid State Chemistry, 2018

Four new coordination polymers [Ni2(HL1)2(L1)3(BTC)2]·6H2O (1), [Ni2(L1)3(HBTC)2]·4H2O (2), [Cd2(... more Four new coordination polymers [Ni2(HL1)2(L1)3(BTC)2]·6H2O (1), [Ni2(L1)3(HBTC)2]·4H2O (2), [Cd2(L2)(BTC)(H2O)3]·2H2O (3) and [Cd2(HL2)(BTCA)] (4) were synthesized by reactions of nickel(II)/ cadmium(II) salts with rigid ligands of 1,4-di(1H-imidazol-4-yl)benzene (L1), 1,3-di(1-imidazolyl)−5-(4H-tetrazol-5-yl)benzene (HL2) and polycarboxylic acids of 1,3,5-benzenetricarboxylic acid (H3BTC), 1,2,4,5-benzenetetracarboxylic acid (H4BTCA), respectively. The structures of the complexes were determined by single crystal X-ray diffraction analysis. The complex 1 is one-dimensional (1D) chain while 2 is a (4, 4)-connected two-dimensional (2D) layered structure with 2D → 2D parallel interpenetration. Complex 3 is a rare tetranodal (3,4)-connected three-dimensional (3D) CrVTiSc architecture with Point (Schläfli) symbol of (4·82)(4·84·10)(42·82·102)(83), and compound 4 has the 2D network with (4,4) topology based on the [Cd2(COO)4] SBUs. The weak interactions such as hydrogen bonds and π···π stacking contribute to stabilize crystal structure and extend the low-dimensional entities into high-dimensional frameworks. The UV–vis absorption spectra of 1 – 4 are discussed. Moreover, the photo luminescent properties of 3 and 4 and gas sorption property of 2 have been investigated.

Research paper thumbnail of Series of Cadmium(II) Coordination Polymers Based on a Versatile Multi-N-Donor Tecton or Mixed Carboxylate Ligands: Synthesis, Structure, and Selectively Sensing Property

ACS Omega, 2019

Five Cd(II) metal−organic frameworks (MOFs), [Cd(HL) 2 ] (1) , [ C d (H L) 2 (H 2 O) 2 ] (2) , [ ... more Five Cd(II) metal−organic frameworks (MOFs), [Cd(HL) 2 ] (1) , [ C d (H L) 2 (H 2 O) 2 ] (2) , [ C d 3 (H L) 2 (o b d a) 2 ] (3) , [Cd 2 (HL) 2 (ohmbda)(DMA)(H 2 O)] (4), and [Cd 2 (HL)(btc)(H 2 O) 2 ]· 3H 2 O (5), were prepared by reactions of Cd(NO 3) 2 ·4H 2 O with 1-(1H-imidazol-4-yl)-4-(4H-tetrazol-5-yl)benzene (H 2 L) or mixed carboxylate ancillary ligands of 1,2-benzenedicarboxylic acid (H 2 obda), 5-hydroxy-1,3-benzenedicarboxylic acid (H 2 ohmbda), and 1,3,5-benzenetricarboxylic acid (H 3 btc), respectively. Their structures have been characterized by single-crystal X-ray diffraction, elemental analysis, infrared spectroscopy (IR), thermogravimetric analysis, and powder X-ray diffraction. Compounds 1 and 2 are supramolecular isomeric frameworks without consideration of the solvent molecules. Complex 1 exhibits a binodal (3, 5)-connected two-dimensional (2D) layer structure with the point (Schlafi) symbol of (5 2 · 6)(5 5 ·6 4 ·7), while complex 2 shows a 2D + 2D → 3D (three-dimensional) framework. Complex 3 is a (3, 5, 6)-connected tetranodal 3D net with the point (Schlafi) symbol of (4·8 2) 2 (4 5 ·6·8 4) 2 (4 5 ·6 5) 2 (4 8 ·6 6 ·8). Compound 4 is a (3, 3, 8)-connected trinodal 3D net with the point (Schlafi) symbol based on a binuclear [Cd 2 N 2 O] subunit, while 5 is a 2-nodal (3, 4)-connected 2D V 2 O 5-type network based on [Cd 2 N 2 (COO) 2 ] SBU. The studies of molecular sensing properties show that the luminescent MOFs can be employed as fluorescent sensors for the detection of Fe 3+ and nitro compounds. Compound 1 and 3 exhibit quenching responses for Fe 3+ in dimethylformamide solution with detection limits of 2.3 × 10 −6 and 8.6 × 10 −7 M, respectively. Meanwhile, compound 5 can sense 4-nitrophenol with a detection limit as low as 5.75 × 10 −7 M. ■ INTRODUCTION Metal−organic frameworks (MOFs) have aroused enormous interest in the field of crystal engineering because of their fascinating structures and potential applications such as gas storage and separation, 1−4 catalysis, 5,6 luminescence, and sensing. 7−12 Structurally, MOFs are infinite structures constructed from organic ligands and metal ions/clusters connected via coordination interactions. Therefore, the functionalities of MOFs are mainly attributable to the nature of the organic ligands and metal centers. 13,14 For example, the luminescent MOFs consisting of π-conjugated organic ligands and d 10 metal centers possess excellent luminescence emission properties and have received particular attention as chemical sensors for sensing nitroaromatic compounds and heavy-metal ions because of their high selectivity and sensitivity, quick response, and recoverability. 15−21 For example, the Wang group synthesized the complex {[Tb(L)1.5(H 2 O)]·DMA· 4H 2 O} n [N-heterocyclic dicarboxylic (2-pyrimidin-5-yl) ter-ephthalic acid (H 2 L) ligand], which can sense Fe 3+ as low as 7.13 × 10 −5 M. 22 Similarly, the crystalline product of [Cd(L 2)0.5(bipy)] shows highly selective sensing property for Fe 3+ ions. 23 As for the organic ligands, both of the nitrogen-rich ligands and carboxylic acids are most effective building units for the assembly of various MOFs because the multi-N and-O coordination atoms are easily apt to link with metal centers. 24−27 Particularly, the polyazaheteroaromatic ligands can exhibit flexible coordination modes to build diverse MOFs. 28−33 In our previous study, we have deliberately designated multi-N-donor ligands containing 1H-imidazol-4-yl groups to construct a series of porous frameworks exhibiting favorable gas adsorption properties because of the increasing interaction between the adsorbate and uncoordinated N binding sites as elaborately elucidated by Grand Canonical Monte Carlo simulation calculations. 34−36 Besides the polyazaheteroaromatic ligands, carboxylic acid ligands are another kind of building units for constructing MOFs due to

Research paper thumbnail of Effect of Synergistic Interplay between Surface Charge, Crystalline Defects, and Pore Volume of MIL-100(Fe) on Adsorption of Aqueous Organic Dyes

Ind. Eng. Chem. Res., 2020

We herein report that the morphology, size, and surface charge status of MIL-100(Fe) micro/nanopa... more We herein report that the morphology, size, and surface charge status of MIL-100(Fe) micro/nanoparticles can be tailored by adding a coordination modulator (HF or tetramethylammonium hydroxide) to the reaction system. Interestingly, the adsorption capacities of low-crystallinity MIL-100(Fe) and MIL-100(Fe)-TMA toward Congo red (CR) and acid chrome blue K (AC) were found to be significantly larger than that of the high-crystallinity MIL-100(Fe)-HF adsorbent, whereas there was little difference in the adsorption capacities of the three MIL-100(Fe) toward methyl orange (MO) and methylene blue (MB). The adsorption uptake of MIL-100-(Fe)-TMA toward the anionic dyes (CR, AC, and MO) was found to be highest, whereas the adsorption uptake of MIL-100(Fe) toward the cationic dye (MB) was the highest owing to different adsorption mechanisms. This adsorption behavior could be rationalized based on the morphological characteristics and crystal structure defects, zeta potential, and pore volume of MIL-100(Fe) and the adsorption characteristics and molecular structure of the dye. It was revealed that the adsorption performance of MIL-100(Fe) micro/nanoparticles is governed by the synergistic interplay between electrostatic, hydrophobic, and π–π stacking interactions, pore volume, crystal structure defects, and steric hindrance of the adsorbent.