Design of Efficient, Hierarchical Porous Polymers Endowed with

Subscriber access provided by BUFFALO STATE

Energy, Environmental, and Catalysis Applications

Design of efficient, hierarchical porous polymers endowed with tunable structural base sites for direct catalytic elimination of COS and H2S Jinxing Mi, Fujian Liu, Wei Chen, Xiaoping Chen, Lijuan Shen, Yanning Cao, Chaktong Au, Kuan Huang, Anmin Zheng, and Lilong Jiang ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.9b09149 • Publication Date (Web): 29 Jul 2019 Downloaded from pubs.acs.org on July 29, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Materials & Interfaces

Design of efficient, hierarchical porous polymers endowed with tunable structural base sites for direct catalytic elimination of COS and H2S

Jinxing Mi†, Fujian Liu*,†, Wei Chen‡, Xiaoping Chen†, Lijuan Shen†, Yanning Cao†, Chaktong Au†, Kuan Huang§, Anmin Zheng‡,¶ and Lilong Jiang*,†

†

National Engineering Research Center of Chemical Fertilizer Catalyst (NERC-CFC),

School of Chemical Engineering, Fuzhou University, Gongye Street 523, Fuzhou, 350002, China. E-mail: [email protected]; [email protected] ‡

National Center for Magnetic Resonance in Wuhan, State Key Laboratory of

Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, China. §

Key Laboratory of Poyang Lake Environment and Resource Utilization of Ministry

of Education, School of Resources Environmental and Chemical Engineering Nanchang University, Nanchang, 330031, China. ¶

School of Materials Science and Engineering, Zhengzhou University, Zhengzhou,

Henan 450051, P. R. China.

1

ACS Paragon Plus Environment

ACS Applied Materials & Interfaces 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Abstract Hydrogen sulfide (H2S) is malodorous and highly toxic, and its selective removal from industrial feedstocks is highly recommended for safety and environment protection. We report here a class of nitrogen-functionalized, hierarchical porous polymers (N-HPPs) synthesized from one-step alkylation-induced crosslinking without any involvement of templates. The as-engineered N-HPPs are large in BET surface area (792~1397 m2/g) and endowed with hierarchical porosity. The incorporated nitrogen species of N-HPPs act as structural base sites with properties that can be precisely controlled. By molecular simulation, the enhanced interactions between N-HPPs and H2S were verified. The synthesized N-HPPs shows superb capacities for H2S adsorption (9.2 mmol/g at 0 °C, 1.0 bar) and displays satisfactory IAST H2S/N2 and H2S/CH4 selectivity (88.3 and 119.6, respectively, at 0 °C). Catalyzed by the structural base sites located in the N-HPPs, the COS together with its derived H2S can be effectively eliminated under mild conditions. KEYWORDS: Hierarchical porous polymers, DFT calculation, structural base sites, H2S selective capture, H2S oxidation

2


Page 2 of 33

Page 3 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


1. INTRODUCTION Traditional fossil fuels such as coal, crude petroleum and natural gas contain sulfur impurities that would result in the formation of sulfides.1–3 As a result, hydrogen sulfide (H2S) and carbonyl sulfide (COS) are widely present in feedstocks such as fuel gas, syngas and biogas,4,5 which are extensively used for the production of ammonia,6 hydrogen,7 alcohols,8 olefins and biofuels.9 In general, the presence of H2S and/or COS in industrial processes is unacceptable because they deactivate metal catalysts and are destructive to facilities as well as transportation equipment.10–12 Furthermore, H2S is highly toxic gas, and is harmful to human health and global environment.13,14 Therefore, the development of efficient technologies for selective removal of H2S to meet safety requirements is urgent.15 So far, the classical Claus technique has been widely applied for selective removal of H2S. However, the Claus process has drawbacks such as high cost and the presence of residual H2S (3−5%) in the tail gas due to thermodynamics limitation.16,17 Other methods such as cryogenic separation, membrane separation and selective adsorption show improved performance.18–20 Among them, selective adsorption is facile and efficient and has been widely applied in recent years.14,21 To reduce cost and make the technology sustainable and environment-benign, great efforts have been paid to develop solid adsorbents, such as metal oxides, MOFs, zeolites, carbons, and composite materials.14,22–25 Through the regulation of porosity and base sites, solid adsorbents can be synthesized with enhanced interaction with H2S, displaying much improved adsorption properties and reusability.26,27 Nevertheless, the adsorbed and separated H2S needs further treatment to avoid secondary pollutions.28 In addition, the poor regeneration of adsorbents could result in abundant solid wastes,14,22,28 which seriously threaten the safety of the chemical industry. 3



Page 4 of 33

Compared to the physical methods, the direct conversion of H2S to elemental sulfur by catalytic oxidation is more promising because it is green, low cost, and free from thermodynamic limitation, and can be carried out under mild conditions.29–31 Using the catalytic route, H2S in low concentrations from industrial tail gas and COS hydrolysis can be completely eliminated. The traditional catalysts used for H2S oxidation are metallic, and problems such as easy deactivation, poor water tolerance and unsatisfactory sulfur selectivity are inevitable.32–34 Recently, nitrogenfunctionalized porous carbons have been successfully used as metal-free catalysts for H2S oxidation, having sulfur tolerance superior to that of metallic catalysts.35–37 More importantly, the nitrogen-containing base sites have strong aﬃnity with H2S, making the selective capture of H2S possible. To the best of our knowledge, there is no report on dual-functional porous materials for the selective capture and oxidation of H2S. It is hence a great challenge to synthesize porous materials through rational engineering of both porosity and nitrogen sites to simultaneously achieve high adsorption capacity, selectivity, as well as enhanced catalytic activity for H2S capture and oxidation. Herein, we illustrate a facile and general alkylation-induced hypercross-linking method for the synthesis of nitrogen-functionalized hierarchical porous polymers (N-HPPs) that are endowed with nitrogen-containing structural base sites. By means of molecular simulation, pyridine, bipyridine, and hexamethylenetetramine (HMTA) were found to show strong hydrogen-bond interactions with H2S. Without the need of templates,

these

molecules

undergo

hypercross-linking

with

1,4-bis(chloromethyl)benzene to form hierarchical micro-meso-macroporous N-HPPs. The provision of the 3-dimensional nanopores and abundant structural base sites 4


Page 5 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


enables high capture of H2S while minimizing N2 and CH4 adsorption, thereby increasing the Ideal Adsorption Solution Theory (IAST) adsorption selectivity of H2S among gases such as N2, and CH4.38,39 The performance of N-HPPs for H2S adsorption is far better than those of a large majority of reported porous materials. Besides the ability for H2S capture, the N-HPPs with unique micro-meso-macropores and controllable surface wettability facilitate the diffusion of gaseous molecules. Furthermore, with the grafted structural base sites, the N-HPPs are active in desulphurization, showing superior activity and commendable stability in COS hydrolysis and H2S selective oxidation, that are usually difficult to deal with using solo porous polymer adsorbents and catalysts. With excellent performance and reusability for the capture as well as catalytic conversion of sulfides, the N-HPPs can be applied to tackle situations that require the separate use of adsorbents and catalysts. 2. EXPERIMENTAL SECTION 2.1 Synthesis of N-HPPs N-HPPs,

namely,

N-HPP-3-aminophenol

N-HPP-p-phenylenediamine, and

N-HPP-HMTA,

were

N-HPP-bipyridine, synthesized

through

alkylation-induced hypercross-linking of selected nitrogen-containing monomers with 1,4-bis(chloromethyl)benzene in the presence a Lewis acid catalyst. In brief, 1.0 g of 1,4-bis(chloromethyl)benzene was dissolved in 15.0 mL of 1,2-dichloroethane, and then 3.0 mL of SnCl4 or TiCl4 was added to the mixture at 0 °C under vigorous stirring.

Subsequently,

0.8

g

of

nitrogen-containing

monomer

(i.e.,

p-phenylenediamine, bipyridine, HMTA or 3-aminophenol) was added into the 5



mixture under static condition. The reaction was performed at 75 °C for 24 h under N2. The formed solid was filtered out and washed thoroughly with hot anhydrous ethanol to remove residual reactants and catalyst. The crude product was activated with isopropylamine, followed by drying under vacuum at 60 °C for 24 h. The prepared samples were denoted as N-HPP-x, where x is the nitrogen-containing monomers (i.e., p-phenylenediamine, bipyridine, 3-aminophenol or HMTA). 2.2 Synthesis of N-HPP-pyridine N-HPP-pyridine was synthesized from a combination of radical copolymerization and alkylation-induced hypercross-linking processes. Typically, 1 mL of vinylbenzyl chloride and 0.78 mL of 4-vinylpyridine were dispersed into 30 mL of 1,2-dichloroethane, followed by the addition of 0.05 g of azobisisobutyronitrile (AIBN) initiator. Copolymerization was conducted by heating the mixture at 80 °C for 24 h for the generation of a sticky copolymer with linearity characteristics. To get the hypercross-linked networks, 4.0 mL of TiCl4 was then introduced into the mixture at 0 °C under vigorous stirring, and the reaction was performed at 80 °C for another 24 h under the protection of N2. The resultant solid was filtered out and washed thoroughly with hot anhydrous ethanol and HCl to remove residual reactants and catalyst. The raw product was activated with isopropylamine, followed by drying under vacuum at 60 °C for 24 h. The synthesized sample is herein denoted as N-HPP-pyridine. 2.3 Synthesis of HPP For comparison, hierarchical porous polymer without nitrogen doping (HPP) was 6


Page 6 of 33

Page 7 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


synthesized from self cross-linking of 1,4-bis(chloromethyl)benzene in the presence of a Lewis acid catalyst. Typically, 2.0 g of 1,4-bis(chloromethyl)benzene was dissolved in 15.0 mL of 1,2-dichloroethane, and then 3.0 mL of SnCl4 or TiCl4 was added to the mixture at 0 °C under vigorous stirring. Subsequently, the reaction was performed at 75 °C for 24 h under N2. The formed solid was filtered out and washed thoroughly with hot anhydrous ethanol to remove residual reactants and catalyst, and dried under vacuum at 60 °C for 24 h. The sample is herein denoted as HPP. 3. RESULTS AND DISCUSSION

Scheme 1. Synthetic route of N-HPPs.

There are numerous kinds of nitrogen-containing monomers, and it is not realistic to test all of them for the synthesis of N-HPPs. In a previous work, pyridine was found to have strong affinity to acidic gas such as CO2.40 In the present work, we selected pyridine, bipyridine, HMTA, p-phenylenediamine and 3-aminophenol according to the results of molecular dynamics simulation. Through the use of the selected molecules as building blocks, it is possibe to derive N-HPPs that are large in 7



Page 8 of 33

specific surface area as well as endowed with hierarchical porosity and nitrogen-containing structural base sites effective for enhanced interaction with H2S. The procedure for the synthesis of N-HPPs is illustrated in Scheme 1. Owing to their high affinity to H2S and suitable polymerization activities, the selected four together with pyridine were used as monomers for the construction of N-HPPs, adopting the alkylation-induced hypercross-linking technique. There was no need to add any templates, and 1,4-bis(chloromethyl)-benzene or 4-vinylbenzyl chloride was employed as crosslinker. According to the monomers, the N-HPPs are herein denoted as

N-HPP-p-phenylenediamine,

N-HPP-bipyridine,

N-HPP-HMTA,

N-HPP-3-aminophenol and N-HPP-pyridine, respectively.

Figure 1. (A) N2 adsorption isotherms at -196 °C, (B) pore size distributions, (C) C1s and (D) N1s XPS spectra, (E) FT-IR spectra, and (F) TG curves of N-HPPs. The isotherms for N-HPP-pyridine,

HPP,

N-HPP-bipyridine,

N-HPP-p-phenylenediamine

and

N-HPP-3-aminophenol are offset by 500, 900, 1600, 2100, and 3000 cm3/g along the vertical for clarity, respectively. 8


Page 9 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


We controlled the contents and structrues of nitrogen-containing structural base sites in the N-HPPs to tune their porosity and instrinsic properties. Depicted in Figure 1A&B are the N2 isotherms and pore size distribution of the samples. The textural parameters of N-HPPs are summarized in Table 1. With small N2 uptake at low relative pressure but large N2 uptake at high relative pressure, all the samples display type-IV isotherms. It is noted that the N2 uptakes display a steep increase at relative pressure of 0.9–0.975. The BET surface areas and total pore volumes of the N-HPPs are 792–1397 m2/g and 0.55–0.83 cm3/g, respectively. In view of the fact that the pore size distribution spreads from 0 to 140 nm, it is considered that the N-HPPs are endowed with micro- as well as meso- and macropores. That is because in the initial stage

of

N-HPPs

preparation,

the

nitrogen

monomers

crosslink

with

1,4-bis(chloromethyl)benzene to form soluble oligomers of low molecular weight, resulting in the basic microporous structures of N-HPPs. With the proceed of polymerization, there is increase of crosslinking and molecular weight. Consequently the polymer networks become insoluble even in a suitable solvent. And with phase separation, there is random aggregation of polymer fragments, resulting in the formation of meso- and macroporous structures in N-HPPs. Therefore, the phase separation in a suitable solvent is crucial for the formation of hierarchical porosity in polymers.41 The corresponding volume ratios of the three kinds of pores were calculated and are recorded in Table 1. Beside the porous structures, the nitrogen-containing structural base sites in N-HPPs were also investigated. The total nitrogen contents range from 3.0wt% to 9



Page 10 of 33

5.1wt%, with that of N-HPP-bipyridine being the highest and that of N-HPP-pyridine the lowest (Table 1). The discrepancy in total nitrogen content across the N-HPPs could be a result of difference in activity across the nitrogen monomers during Table 1. Nitrogen contents and textural parameters of the synthesized N-HPPs SBET (m2/g)

Vp (cm3/g)

Volume ratio [b]

3.5

1186±35

0.78±0.021

1.0/2.14/2.63

N-HPP-bipyridine

5.1

1350±32

0.59±0.017

1.0/0.75/0.17

N-HPP-HMTA

3.3

1397±39

0.83±0.025

1.0/0.93/0.42

N-HPP-3-aminophenol

3.2

1229±28

0.72±0.022

1.0/1.34/0.47

N-HPP-pyridine

3.0

792±19

0.55±0.015

1.0/0.74/0.91

HPP

-

1605±42

0.69±0.019

1.0/1.15/0.67

Samples

N contents (wt%) [a]

N-HPP-p-phenylenediamin e

[a] Measured by elemental analysis. [b] Volume ratio of micro/meso/macropores.

hyper-cross-linking. The structures of nitrogen species incorporated in N-HPPs were examined by XPS (Figure 1C&D). The C1s spectra of all N-HPPs can be deconvoluted into two peaks at around 284.6 eV and 285.9 eV, attributable to C−C and C−N signals, respectively. The N1s spectrum of N-HPP-HMTA can be deconvoluted into two peaks at around 399.1 eV and 402.0 eV. The formation of quaternized

amine

is

a

result

of

tertiary

amine

quaternization

with

1,4-bis(chloromethyl)benzene, a side reaction of hyper-cross-linking. The N1s peak positions of N-HPP-p-phenylenediamine and N-HPP-3-aminophenol are similar to 10


Page 11 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


that of N-HPP-HMTA, because the N1s signals of primary and tertiary amines are close in binding energy. It is noted that the N1s spectra of N-HPP-bipyridine and N-HPP-pyridine are different from those of the other samples. Beside the weak signal of quaternized amine at around 401.3 eV, there is a much stronger signal of pyridinic nitrogen at around 398.6 eV, indicating limited occurrence of the side reactions. The successful incorporation of selected nitrogen sites in N-HPPs could be further confirmed by FT-IR spectra. The peaks at around 879, 1045 and 1087 cm-1 associated with the signal of C−N bond can be observed over all N-HPPs.42 Over N-HPP-HMTA and N-HPP-p-phenylenediamine, peaks at 1600 cm-1 and 3300 cm-1 ascribable to N−H bond can be observed.42 In the cases of N-HPP-bipyridine and N-HPP-pyridine, peaks at around 1590 cm-1 assignable to pyridinic nitrogen are detected (Figure 1E).43 Furthermore, the 13C solid-state NMR spectra of N-HPPs were recorded and are depicted in Figure S1. The signals associated with the 1,4-bis(chloromethyl)benzene unit (20, 38, 130 and 138 ppm) can be observed over all of the N-HPPs.42,44 Over N-HPP-bipyridine, N-HPP-p-phenylenediamine and N-HPP-HMTA,42,44 signals attributable to nitrogen sites of pyridine ring (141 ppm and 147 ppm), phenylenediamine unit (138 ppm), and tertiary amine group (50 ppm and 53 ppm) are observed. The above results confirm that the N-HPPs are endowed with different kinds of nitrogen groups, and the nitrogen sites in N-HPPs can be fabricated in a task-specific manner. In addition, the synthesized N-HPPs display good thermal stability as a result of their highly cross-linked networks (Figure 1F). Notably, two platforms of TG curve were observed in N-HPP-p-phenylenediamine, which could be 11



Page 12 of 33

attributed to the thermal decomposition of exposed –NH2 and the collapse of polymer networks.45 Obvious platform of TG curve could also be found over N-HPP-3-aminophenol with –NH2 base sites. In contrast, such phenomena cannot be observed over N-HPP-HMTA, N-HPP-pyridine, and N-HPP-bipyridine, in which the nitrogen atoms are confined in the aromatic rings as reflected in the much higher thermal stability. The TG results further illustrate the controllability of nitrogen functionality in N-HPPs. The morphologies of N-HPPs were examined by scanning electron microscopy, and rough surfaces and sponge-like macropores can be observed over the five N-HPPs samples (Figure 2, a−i). In the investigation of inner porous structures by transmission electron

microscopy

(TEM),

there

is

the

detection

of

hierarchical

micro-meso-macropores (Figure 2, j−o), in agreement with the results of N2-adsorption isotherms. The formation of macropores can be a result of random aggregation of microporous and mesoporous architectures. The above results confirm the unique hierarchical porosity of the prepared N-HPPs. With rich hierarchical porosity, large BET surface area and controlled nitrogen-containing structural base sites, N-HPPs are effective in the selective capture of H2S and CO2. We performed Grand Canonical Monte Carlo (GCMC) simulations to study gas adsorption on the N-HPPs. The aim is to gain insight into the distribution of gas in N-HPPs based on radial distribution function (RDF), which describes how density varies as a function of distance from a reference particle. Figure 3A and Figure S2 show the RDF profiles of systems containing N-HPPs and different gases. 12


Page 13 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


It is found that there is abundant formation of hydrogen bonds between N-HPPs and H2S according to short interactional distances. For example, the strong peaks start from 2.0 Å between N, H of N-HPPs and H, S of H2S, suggesting structures of double

Figure 2. SEM images of (a, b) N-HPP-HMTA, (c, d) N-HPP-pyridine, (e, f) N-HPP-bipyridine, (g, h) N-HPP-p-phenylenediamine and (i) N-HPP-3-aminophenol; TEM images of (j, k) N-HPP-HMTA,

(l)

N-HPP-bipyridine,

(m,

n)


and

(o)

N-HPP-pyridine.

hydrogen bonding interactions. The H, N atoms of N-HPPs are major sites for binding 13



Page 14 of 33

with H2S. According to the RDF profiles, the site-to-site interaction strengths follow the

order

of

N(N-HPP-p-phenylenediamine)--H(H2S)

>

N(N-HPP-bipyridine)--H(H2S) > N(N-HPP-pyridine)--H(H2S) > N(N-HPP-HMTA)--H(H2S) H(N-HPP-bipyridine)--S(H2S)

> >

H(N-HPP-HMTA)--S(H2S)

>

H(N-HPP-pyridine)--S(H2S)

>

H(N-HPP-p-phenylenediamine)--S(H2S). On the other hand, the RDF distances between N of N-HPPs and C of CO2 start from 3.2 Å, which are longer than those of H2S (2.0 Å). Therefore, the interaction of CO2 is weaker than that of H2S on N-HPPs. In contrast, the RDF profiles of host-guest systems containing N-HPPs and CH4 or N2 are relatively flat and noisy, and the site-to-site distances are even longer than 5.0 Å. Hence, the adsorption of CH4 and N2 on the N-HPPs can be classified as van der Waals interaction.

Figure 3. (A) RDF of systems containing (a) N-HPP-bipyridine, (b) N-HPP-HMTA and (c) 14


Page 15 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


N-HPP-p-phenylenediamine with different gases (H2S, CO2, CH4 and N2) derived from Grand-canonical Monte Carlo (GCMC) simulations. (B) Schematics of CO2 and H2S adsorbed on the synthesized N-HPPs based on DFT calculation; BE is the binding energies between H2S and N-HPPs.

Quantum chemistry calculations were then performed to study the geometry and binding energy of the gas molecules adsorbed on N-HPPs (Figures 3B and S3). Notably, there are strong hydrogen bondings between the N, H atoms of HPPs and H, S of H2S with distances in the range of 2.039–2.715 Å (Figure 3B), and such adsorption conformations are in good agreement with the above GCMC predictions. In the case of CO2 adsorption, hydrogen bonding is between N-HPPs and CO2 through the pairing of N and O sites. The distances between the N and O atoms are in the range of 2.510 to 3.301Å, which are larger than that of N-HPPs interaction with H2S, revealing stronger interaction in the latter. As shown in Figure S3, with long bonding distances and low binding energies, the interaction of N2 and CH4 with N-HPPs are exclusively van der Waals, and the binding of N2 and CH4 with N-HPPs are weaker than that of H2S or CO2. On the basis of adsorption structures, the binding energies can be quantificationally obtained, which is -17.39~-27.99 kJ/mol between N-HPPs and H2S, and -13.65~-27.42 kJ/mol between N-HPPs and CO2. Although the adsorption energies of CO2 and H2S on the N-HPPs are somewhat comparable, the number of H2S adsorption modes and self interactions (guest-guest interactions) by hydrogen bonding are larger than that of CO2, which can lead to stronger adsorption of H2S than that of CO2. In contrast, much lower binding energies (-6.70~-8.02 and -8.54~-10.29 kJ/mol) were obtained for N2 and CH4 adsorption on N-HPPs. 15



Therefore, the N-HPPs show much stronger interaction with H2S and CO2 than with N2 and CH4, in accord with the results of RDF analysis. To verify the theoretical results, we obtained the adsorption isotherms of H2S, CO2, CH4, and N2 at 0 °C and 25 °C over N-HPP-HMTA, N-HPP-bipyridine and N-HPP-pyridine (Figure 4A–D). Overall, the samples show impressive capacities for H2S and CO2 adsorption. For example, the CO2 adsorption capacities at 1 bar are 3.04–5.67 mmol/g at 0 °C and 2.64–3.93 mmol/g at 25 °C. At a lower pressure of 0.15 bar, the capacities are 1.22–2.59 mmol/g at 0 °C and 0.82–1.82 mmol/g at 25 °C. Beside the porous structure of N-HPPs, the binding strength of nitrogen sites with H2S and CO2 also has an influence on adsorption capacity.46 It is hence not surprising to observe that despite HPP is large in BET surface area (Table 1), it is low in H2S and CO2 adsorption capaciy (Figure S4). For easy comparison, the H2S capacities of some widely used adsorbents and pure HPP are displayed in Figure 4E, and the synthesized N-HPPs show capacities for H2S capture much higher than those of the referred samples. The poor H2S adsorption capacity of N-HPP-3-aminophenol can be attributed to the fact that a large amount of nitrogen in the frameworks has been protonated as implied in XPS analysis (Figure 1C&D), and the poor H2S adsorption capacity of HPP should be attributed to the absence of nitrogen sites in the sample. The H2S adsorption capacity of N-HPP-HMTA is the highest because of the strong interaction of tertiary amine with H2S (Figure 3) as well as its high BET surface area. Although N-HPP-bipyridine is the highest in total nitrogen content, its H2S adsorption capacity is inferior to that of N-HPP-HMTA. This is because the interaction of 16


Page 16 of 33

Page 17 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


pyridinic nitrogen with H2S is relatively weak as compared with that of HMTA. Similar trends can be observed in the capture of CO2. It is noteworthy that the N-HPPs of the present study are higher than HPP and most of the adsorbents reported in the literature in terms of H2S and CO2 adsorption capacity (Figure 4E & Table S1). While this preliminary study ignores the heterogeneity of the system, the DFT calculation suggests a plausible mechanism to understand the interaction between N-HPPs and acid gases (H2S and CO2). The properties of N-HPP-HMTA and N-HPP-bipyridine for H2S and CO2 adsorption are consistent with the results of DFT calculation (Figures 3, S2 & S3).

Figure 4. Adsorption isotherms of (A) H2S, (B) CO2, (C) CH4 and (D) N2 over (a) N-HPP-HMTA, (b) N-HPP-bipyridine, and (c) N-HPP-pyridine at 0 °C (solid) and 25 °C (hollow); (E) H2S adsorption isotherms (a) N-HPP-HMTA, (b) N-HPP-pyridine, (c) UIO-66, (d) HPP, (e) Activated carbon, (f) Zeolite A and (g) SBA-15 at 0 °C; (F) Cycling of H2S adsorption on (a) N-HPP-HMTA, (b) N-HPP-3-aminophenol, (c) N-HPP-pyridine, (d) N-HPP-bipyridine and (e) N-HPP-p-phenylenediamine at 0 °C. 17



In addition to H2S adsorption capacity, H2S selectivity among gases such as CO2, N2, and CH4 is also a relevant parameter used to evaluate solid adsorbents for selective capture of H2S. The N2 and CH4 adsorption isotherms of N-HPP-HMTA, N-HPP-bipyridine and N-HPP-pyridine at 0 and 25 °C were measured, and the results are shown in Figure 4 C&D. It was found that the samples can only adsorb a limited amount of N2 and CH4, which are almost two orders of magnitude lower than the adsorbed amounts of H2S and CO2. The phenomenon should be a result of the unique micro-meso-macroporous structures and active nitrogen sites of N-HPPs designed for H2S and CO2 adsorption. It has been reported that the uptake of N2 and CH4 in porous materials is sensitive to pore sizes due to the pure physisorption; enlarging the pore size would weaken N2 and CH4 interaction with channel walls and thus disrupt their adsorption.41 Therefore, introducing meso-macropores into the frameworks of solid adsorbents is an efficient way to facilitate selective adsorption of H2S and CO2 in the presence of N2 and CH4. The adsorption selectivity in cases of H2S/CO2, H2S/CH4 and H2S/N2 were calculated according to the IAST model, and the results are compiled in Table 2.43 Notably, all N-HPPs are impressive in terms of IAST selectivity: 16.6– 185.1 (H2S/CH4) and 83.5–119.6 (H2S/N2) at 0 °C and 25 °C. Similar to H2S adsorption capacities, the difference in H2S selectivity among the N-HPPs could be attributed to the discrepancy in nitrogen content, porous structure and binding energy of gases with the nitrogen sites. Moreover, it is found that a rise of adsorbent temperature has a positive effect on H2S and CO2 selectivity. It is because due to the strong interaction of nitrogen species with H2S and CO2, the temperature dependence 18


Page 18 of 33

Page 19 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


of H2S and CO2 adsorption is less sensitive than that of N2 and CH4 adsorption.42,43 Notably, a high binding energy between N-HPPs and gases (based on DFT calculation) leads to enhanced H2S and CO2 selectivity. Therefore, although HPP is large in surface area, its capacity and selectivity for H2S and CO2 capture are much lower than that of N-HPPs owing to the absence of specific nitrogen sites (Figure S4, Table 2). It Table 2. IAST selectivity of gases over the N-HPP samples Samples

IAST selectivity[a]

T (°C) H2S/CO2

H2S/CH4

H2S/N2

CO2/CH4

CO2/N2

0

1.3

29.0

87.1

22.3

66.9

25

1.1

29.8

95.1

26.8

85.5

0

1.7

88.3

97.6

51.9

57.3

25

1.6

185.1

89.2

120.6

58.2

0

1.8

61.6

119.6

34.9

67.8

25

1.1

116.3

111.3

108.2

103.5

0

2.2

36.0

83.5

16.6

38.5

25

1.3

22.9

96.3

17.6

73.8

0

2.5

20.6

113.1

8.3

45.6

25

1.7

16.6

97.4

9.9

58.5

0

2.0

8.7

26.7

4.4

26.7

25

1.9

9.2

55.9

4.8

29.4

SBA-15

0

2.6

24.1

63.2

9.3

55.4

UiO-66

0

3.1

30.3

88.1

9.7

28.4

Activated carbon

0

2.0

42.5

89.8

6.1

13.1

Zeolite A

0

1.6

36.1

64.5

5.6

64.2

N-HPP-HMTA

N-HPP-bipyridine

N-HPP-pyridine


N-HPP-3-aminophenol

HPP

[a] Calculated according to the IAST for a mixture of H2S/CO2 (0.1/0.1); H2S/CH4 (0.1/0.9), H2S/N2 (0.1/0.9), CO2/CH4 (0.1/0.9) and CO2/N2 (0.1/0.9) at 1 bar. 19



is also noted that the H2S and CO2 selectivity of the synthesized N-HPPs are comparable to or even higher than most of the adsorbents reported in literatures (Tables S2). In addition, the N-HPPs are reusable, showing H2S adsorption capacities at 0 °C comparable to those of the fresh samples across ten adsorption-desorption cycles (Figure 4F). In the cases of CO2 capture, satisfactory reusability could also be observed (Figure S5). Beside being used for H2S capture, N-HPPs can be directly used as novel metal free catalysts for H2S selective oxidation. The plots of H2S conversion over N-HPPs versus reaction temperature are shown in Figure 5A. Notably, N-HPP-HMTA shows

Figure 5. Effect of reaction temperature on (A) H2S conversion, (B) sulfur selectivity, (C) activation energy of (a) N-HPP-HMTA, (b) N-HPP-pyridine, (c) N-HPP-bipyridine, (d) N-HPP-p-phenylenediamine, (e) N-HPP-3-aminophenol and (f) HPP in H2S selective oxidation, and (D) Time-on-stream behavior and water tolerance of (a & b) N-HPP-HMTA (c & d) commercial Fe2O3 and (e & f) g-C3N4 in H2S selective oxidation at 180 °C. Reaction condition: catalyst (0.1 g), H2S/O2/N2=0.5/0.25/99.25 (wt%), WHSV (6000 mL·g-1·h-1). (E) COS hydrolysis over N-HPP-HMTA and HKUST‐1 at different temperature (black) and time-on-stream behavior 20


Page 20 of 33

Page 21 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(red, 70 °C). Reaction conditions: catalyst 0.2 g, feed gas 100 mg/cm3 COS/N2, WHSV (6000 mL·g-1·h-1), water temperature 40 °C. (F) Influence of flow velocity on COS conversion over N-HPP-HMTA. Reaction conditions: catalyst 0.2 g, feed gas 100 mg/cm3 COS/N2, water temperature 40 °C.

much higher activities in comparison with the other N-HPPs. For instance, H2S conversion over N-HPP-HMTA was nearly 92% at 160 °C, which can be further improved to 100% at 180 °C. On the other hand, H2S conversions over the other N-HPPs only range from 32.5% to 82.1% at 200 °C. Nonetheless, the conversion of H2S catalyzed by HPP was as low as 10.7% at 200 °C, suggesting that the introduction of nitrogen sites plays key role in H2S selective oxidation. It is noted that N-HPP-HMTA is higher than Pd-SnO2 and other nitrogen-containing nanomaterials in catalytic activity (Table S3). In addition to good activity, N-HPP-HMTA shows selectivity to sulfur close to 100% within the entire temperature range (100–200 °C), and the same could also be observed over N-HPP-bipyridine and N-HPP-pyridine (Figure 5B). In comparison, N-HPP-p-phenylenediamine and N-HPP-3-aminophenol are a little less sensitive in H2S selective oxidation, showing sulfur selectivities ranging from 92% to 100% at different reaction temperatures. The phenomenon is attributed

to

deep

oxidation

of

H2S

(H2S+3/2O2=SO2+H2O)

and

sulfur

(S+O2=SO2),14,15 noting that SO2 is an intermediate in H2SO4 production. The decreased

catalytic

performance

of


and

N-HPP-3-aminophenol may be attributed to their low base strength, which weakens their interaction with H2S. The yields of sulfur over the N-HPPs are shown in Figure S6. The variation of H2S conversion and sulfur selectivity follow a similar trend of 21



N-HPP-3-aminophenol

N-HPP-bipyridine (50.22 kJ/mol) > N-HPP-pyridine (43.14 kJ/mol) > N-HPP-HMTA (35.05 kJ/mol). Acting as Lewis basic sites, the grafted nitrogen groups could increase the local basicity of N-HPPs, which facilitates the dissociation of H2S into HS- ions.35,39,47 Owing to the basicity of N-HPPs, there is significant enrichment of HS- ions in N-HPPs. Meanwhile, oxygen molecules could easily diffuse into the pores and are preferentially adsorbed on the nitrogen sites, particularly the pyridine as well as the primary and tertiary amines sites due their electron-donating abilities. The subsequent reaction between concentrated HS- ions and adsorbed oxygen species leads to the formation of elemental sulfur (Figures S7–S9).15,35 Moreover, we investigated the durability and water tolerance of N-HPP-HMTA in the selective oxidation of H2S, which are indubitably important for practical applications because of the usual presence of water, for example, in flue gases. Without the presence of water, N-HPP-HMTA exhibits stable performance in a span of 30 h, constantly showing H2S conversion close to 100%. After introducing 20% of water vapour into the reaction system, there is only slight decline in H2S conversion 22


Page 23 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(from 100% to 97%). The system reaches an equilibrium quickly, and there is no further loss of activity in the 24 h that follows. More interestingly, with the stop of water in put, there is complete recovery of activity. The performance is far better than those of the widely used commercial Fe2O3 and novel g-C3N4 catalysts (Figure 5D). The superior durability of N-HPP-HMTA is attributed to the availability of a large amount of exposed nitrogen sites and the hierarchical nanoporosity. At a water vapour level of 30%, there is a slight decrease of H2S conversion, as well as sulfur selectivity and yield (Figure S10). The above results confirm that N-HPP-HMTA not only shows superior durability, but also exhibits excellent water tolerance, which is essential for industrial application. To the best of our knowledge, this is the first time that N-HPPs were demonstrated as metal-free and water tolerant catalysts in direct selective oxidation of H2S. Additionally, N-HPP-HMTA can also be used as highly efficient and long-lived metal-free catalysts for COS hydrolysis, as illustrated in the Figure 5E. It was observed that N-HPP-HMTA shows much higher COS conversion than the HKUST-1 metal organic framework48 in the whole temperature range, and close to 100% COS conversion is achieved at ca. 50 °C. The excellent activity of N-HPP-HMTA in COS hydrolysis could also be observed at higher flow velocities (6000–12 000 mL g-1·h-1), (Figure 5F). Furthermore, even after continuous reaction of 40 h, there was no detection of any decrease in COS conversion, indicating excellent long-term stability of N-HPP-HMTA for COS hydrolysis. In contrast, there was obvious decrease of activity within 4 h over HKUST-1. The outstanding activities, good stability and 23



Page 24 of 33

enhanced water tolerance of N-HPPs in desulphurization are attributed to the abundantly hierarchical porosity, tunable structural base sites and controllable surface wettability. 4. CONCLUSIONS In summary, a class of N-HPPs endowed with hierarchical nanopores, large specific surface areas and tunable nitrogen-containing structural base sites were synthesized

through

alkylation-induced

hypercross-linking

of

selected

nitrogen-containing monomers. A variety of highly active structural base sites were successfully introduced into N-HPPs using motifs such as pyridine, bipyridine, and HMTA which were identified as H2S-philic by molecular simulation. The N-HPPs show extraordinary capacity for H2S and CO2 capture, showing high IAST selectivity as well as recyclability. Moreover, the N-HPPs are efficient, stable and water-tolerant catalysts for COS hydrolysis and H2S selective oxidation under mild conditions. The present work provides a rational approach for the design and synthesis of dual-functional N-HPPs to enlarge the application potential of porous polymers for desulphurization.

ASSOCIATED CONTENT Supporting Information. Details on characterizations, gas adsorption, DFT calculation and catalytic evaluation of various samples. Textural parameters of N-HPPs, the comparison of CO2 adsorption and CO2/N2 selectivity of N-HPPs with reported porous materials. 24


Page 25 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


AUTHOR INFORMATION Corresponding Author *E-mail: [email protected] *E-mail: [email protected] Author Contributions The manuscript was completed by contributions of all authors. All authors approved the final version of the manuscript. Notes The authors declare no competing financial interest. ACKNOWLEDGEMENTS This work was supported by National Key Research and Development Program of China (2018YFA0209304). The National Natural Science Foundation of China (21825801, 21573150). Natural Science Foundation of Zhejiang Province (LY15B030002). The Program for Qishan Scholar of Fuzhou University (GXRC-18043).

REFERENCES (1) David, T.; Robert, S.; Jonathan, A. F.; Jason, H.; Eric, L.; Lee, L.; Stephen, P.; John, R.; Tim, S.; Chris, S.; Robert, W. Beneficial Biofuels–the Food, Energy, and Environment Trilemma. Science 2008, 325, 270–271. (2) Christophe, M.; Paul, E. The Geographical Distribution of Fossil Fuels Unused When Limiting Global Warming to 2 °C. Nature 2015, 517, 187–190. 25



(3) Liu, Z.; Guan, D. B.; Wei, W.; Davis, S. J.; Ciais, P.; Bai, J.; Peng, S. S.; Zhang, Q.; Hubacek, K.; Marland, G.; Andres, R. J.; Crawford-Brown, D.; Lin, J. T.; Zhao, H. Y.; Hong, C. P.; Boden, T. A.; Feng, K. S.; Peters, G. P.; Xi, F. M.; Liu, J. G.; Li, Y.; Zhao, Y.; Zeng, N.; He, K. B. Reduced Carbon Emission Estimates from Fossil Fuel Combustion and Cement Production in China. Nature 2015, 524, 335–338. (4) Jiao, F.; Li, J. J.; Pan, X. L.; Xiao, J. P.; Li, H. B.; Ma, H.; Wei, M. M.; Pan, Y.; Zhou, Z. Y.; Li, M. R.; Miao, S.; Li, J.; Zhu, Y. F.; Xiao, D.; He, T.; Yang, J. H.; Qi, F.; Fu, Q.; Bao, X. H. Selective Conversion of Syngas to Light Olefins. Science 2016, 351, 1065–1068. (5) Kadam, R.; Panwar, N. L. Recent Advancement in Biogas Enrichment and its Applications. Renew. Sust. Energ. Rev. 2017, 73, 892–903. (6) Wang, P. K.; Chang, F.; Gao, W. B.; Guo, J. P.; Wu, G. T.; He, T.; Chen, P. Breaking Scaling Relations to Achieve Low-temperature Ammonia Synthesis Through LiH-mediated Nitrogen Transfer and Hydrogenation. Nat. Chem. 2017, 9, 64–70. (7) Yao, S. Y.; Zhang, X.; Zhou, W.; Gao, R.; Xu, W. Q.; Ye, Y. F.; Lin, L. L.; Wen, X. D.; Liu, P.; Chen, B. B.; Crumlin, E.; Guo, J. H.; Zuo, Z. J.; Li, W. Z.; Xie, J. L.; Lu, L.; Kiely, C. J.; Gu, L.; Shi, C.; Rodriguez, J. A.; Ma, D. Atomic-layered Au Clusters on α-MoC as Catalysts for the Low-temperature Water-gas Shift Reaction. Science 2017, 357, 389–393.

26


Page 26 of 33

Page 27 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(8) Tao, Y.; Ben, L. F.; Katalin, B. Iron Catalysed Direct Alkylation of Amines with Alcohols. Nat. Commun. 2014, 5, 5602. (9) Peralta-Yahya, P. P.; Zhang, F. Z.; del Cardayre, S. B.; Keasling, J. D. Microbial Engineering for the Production of Advanced Biofuels. Nature 2014, 488, 320– 328. (10)Huang, H. G.; Young, N.; Williams, B. P.; Taylor, S. H.; Hutchings. Purification of Chemical Feedstocks by the Removal of Aerial Carbonyl Sulfide by Hydrolysis Using Rare Earth Promoted Alumina Catalysts. Green Chem. 2008, 10, 571–577. (11)Polychronopoulou, K.; Efstathiou, A. M. Effects of Sol-gel Synthesis on 5Fe-15Mn-40Zn-40Ti-O Mixed Oxide Structure and its H2S Removal Efficiency from Industrial Gas Streams. Environ. Sci. Technol. 2009, 43, 4367–4372. (12)Belmabkhout, Y.; Bhatt, P. M.; Adil, K.; Pillai, R. S.; Cadiau, A.; Shkurenko, A.; Maurin, G.; Liu, G. P.; Koros, W. J.; Eddaoudi, M. Natural Gas Upgrading Using a Fluorinated MOF with Tuned H2S and CO2 Adsorption Selectivity. Nature Energy 2018, 3, 1059−1066. (13)Bostelaar, T.; Vitvitsky, V.; Kumutima, J.; Lewis, B. E.; Yadav, P. K.; Brunold, T. C.; Filipovic, M.; Lehnert, N.; Stemmler, T. L.; Banerjee, R. Hydrogen Sulfide Oxidation by Myoglobin. J. Am. Chem. Soc. 2016, 138, 8476−8488. (14)Shah, M. S.; Tsapatsis, M.; Siepmann, J. I. Hydrogen Sulfide Capture: from Absorption in Polar Liquids to Oxide, Zeolite, and Metal−Organic Framework Adsorbents and Membranes. Chem. Rev. 2017, 117, 9755−9803. 27



(15)Zhang, X.; Tang, Y. Y.; Qu, S. Q.; Da, J. W.; Hao, Z. P. H2S‑selective Catalytic Oxidation: Catalysts and Processes. ACS Catal. 2015, 5, 1053−1067. (16)Pieplu, A.; Saur, O.; Lavxlley, J. C. Claus Catalysis and H2S Selective Oxidation. Catal. Rev. 1998, 40, 409−450. (17)Mohammed, S.; Raj, A.; Shoaibi, A. A.; Sivashanmugam, P. Formation of Polycyclic Aromatic Hydrocarbons in Claus Process from Contaminants in H2S Feedgas. Chem. Eng. Sci. 2015, 37, 91–105. (18)Sun, Q.; Li, H. L.; Yan, J. Y.; Liu, L. C.; Yue, Z. X.; Yu, X. H. Selection of Appropriate Biogas Upgrading Technology-A Review of Biogas Cleaning, Upgrading and Utilisation. Renew. Sust. Energ. Rev. 2015, 51, 521–532. (19)Ma, X. L.; Wang, X. X.; Song, C. S. “Molecular Basket” Sorbents for Separation of CO2 and H2S from Various Gas Streams. J. Am. Chem. Soc. 2009, 131, 5777– 5783. (20)Shah, M. S.; Tsapatsis, M.; Siepmann, J. I. Identifying Optimal Zeolitic Sorbents for Sweetening of Highly Sour Natural Gas. Angew. Chem., Int. Ed. 2016, 55, 5938–5942. (21)Abatzoglou, N.; Boivin, S. A Review of Biogas Purification Processes. Biofuels, Bioprod. Bioref. 2009, 3, 42–71. (22)Othmana, M. A.; Zahida, W. M.; Abasaeed, A. E. Selectivity of Layered Double Hydroxides and Their Derivative Mixed Metal Oxides as Sorbents of Hydrogen Sulfide. J. Hazard. Mater. 2013, 254, 221–227.

28


Page 28 of 33

Page 29 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(23)Ozekmekci, M.; Salkic, G.; Fellah, M. F. Use of Zeolites for the Removal of H2S: A Mini-review. Fuel Process. Technol. 2015, 139, 49–60. (24)Feng, W.; Kwon, S.; Borguet, E.; Vidic, R. Adsorption of Hydrogen Sulfide onto Activated Carbon Fibers: Effect of Pore Structure and Surface Chemistry. Environ. Sci. Technol. 2005, 39, 9744–9749. (25)Seredych, M.; Bandosz, T. J. Reactive Adsorption of Hydrogen Sulfide on Graphite Oxide/Zr(OH)4 Composites. Chem. Eng. J. 2011, 166, 1032–1038. (26)Liu, J.; Wei, Y. J.; Li, P. Z.; Zhao, Y. L.; Zou, R. Q. Selective H2S/CO2 Separation by Metal−Organic Frameworks Based on Chemical-physical Adsorption. J. Phys. Chem. C 2017, 121, 13249−13255. (27)Okonkwo, C. N.; Okolie, C.; Sujan, A.; Zhu, G. H.; Jones, C. W. Role of Amine Structure on Hydrogen Sulfide Capture from Dilute Gas Streams Using Solid Adsorbents. Energy Fuels 2018, 32, 6926−6933. (28)Zheng, X. X.; Shen, L. J.; Chen, X. P.; Zheng, X. H.; Au, C. T.; Jiang, L. L. Amino-modified Fe-terephthalate Metal–Organic Framework as an Efficient Catalyst for the Selective Oxidation of H2S. Inorg. Chem. 2018, 57, 10081– 10089. (29)Shinkarev, V. V.; Glushenkov, A. M.; Kuvshinov, D. G.; Kuvshinov, G. G. Nanofibrous Carbon with Herringbone Structure as an Effective Catalyst of the H2S Selective Oxidation. Carbon 2010, 48, 2004–2012. (30)Duong-Viet, C.; Liu, Y. F.; Ba, H.; Truong-Phuoc, L.; Baaziz, W.; Nguyen-Dinh, L.; Nhut, J. M.; Pham-Huu, C. Carbon Nanotubes Containing Oxygenated 29



Decorating Defects as Metal-free Catalyst for Selective Oxidation of H2S. Appl Catal B: Environ. 2016, 191, 29–41. (31)Zhao, W. T.; Zheng, X. H.; Liang, S. J.; Zheng, X. X.; Shen, L. J.; Liu, F. J.; Cao, Y. N.; Wei, Z.; Jiang, L. L. Fe-doped γ-Al2O3 Porous Hollow Microspheres for Enhanced Oxidative Desulfurization: Facile Fabrication and Reaction Mechanism. Green Chem. 2018, 20, 4645–4654. (32)Zhang, X.; Wang, Z.; Qiao, N. L.; Qu, S. Q.; Hao, Z. P. Selective Catalytic Oxidation of H2S over Well-mixed Oxides Derived From Mg2AlxV1−x Layered Double Hydroxides. ACS Catal. 2014, 4, 1500−1510. (33)Tasdemir, H. M.; Yasyerli, S.; Yasyerli, N, Selective Catalytic Oxidation of H2S to Elemental Sulfur over Titanium Based Ti-Fe, Ti-Cr and Ti-Zr Catalysts. Inter. J Hydrogen. Energy. 2015, 40, 9989−10001. (34)Zhang, F. L.; Zhang, X.; Jiang, G. X.; Li, N.; Hao, Z. P.; Qu, S. Q. H2S Selective Catalytic Oxidation over Ce Substituted La1-xCexFeO3 Perovskite Oxides Catalyst. Chem. Eng. J. 2014, 348, 831–839. (35)Sun, F. G.; Liu, J.; Chen, H. C.; Zhang, Z. X.; Qiao, W. M.; Long, D. H.; Ling, L. C. Nitrogen-rich Mesoporous Carbons: Highly Efficient, Regenerable Metal-free Catalysts for Low-temperature Oxidation of H2S. ACS Catal. 2013, 3, 862-870. (36)Shinkarev, V. V.; Glushenkov, A. M.; Kuvshinov, D. G.; Kuvshinov, G. G. New Effective Catalysts Based on Mesoporous Nanofibrous Carbon for Selective Oxidation of Hydrogen Sulfide. Appl Catal B: Environ. 2009, 85, 180–191.

30


Page 30 of 33

Page 31 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(37)Lei, G. H.; Cao, Y. N.; Zhao, W. T.; Dai, Z. J.; Shen, L. J.; Xiao, Y. H.; Jiang, L. L.

Exfoliation

of

Graphitic

Carbon

Nitride

for

Enhanced

Oxidative

Desulfurization: A Facile and General Strategy. ACS Sustainable Chem. Eng. 2019, 7, 4941−4950. (38)Alivand, M. S.; Tehranib, N. H. M. H.; Shafiei-alavijeh, M.; Rashidib, A.; Kootic, M.; Pourreza, A.; Fakhraie, S. Synthesis of a Modified HF-free MIL-101(Cr) Nano Adsorbent with Enhanced H2S/CH4, CO2/CH4, and CO2/N2 Selectivity. J. Environ. Chem. Eng. 2019, 7, 102946. (39)Kan, X.; Chen, X. P.; Chen, W.; Mi, J. X.; Zhang, J. Y.; Liu, F. J.; Zheng, A. M.; Huang, K.; Shen, L. J.; Au, C. T.; Jiang, L. L. Nitrogen-decorated, Ordered Mesoporous Carbon Spheres as High-efficient Catalysts for Selective Capture and Oxidation of H2S. ACS Sustainable Chem. Eng. 2019, 7, 7609-7618. (40)To, J. W. F.; He, J. J.; Mei, J. G.; Haghpanah, R.; Chen, Z.; Kurosawa, T.; Chen, S. C.; Bae, W. G.; Pan, L. J.; Tok, J. B.-H.; Wilcox, J.; Bao, Z. N. Hierarchical N-doped Carbon as CO2 Adsorbent with High CO2 Selectivity from Rationally Designed Polypyrrole Precursor. J. Am. Chem. Soc. 2016, 138, 1001–1009. (41)Zhang, Y. L.; Wei, S.; Liu, F, J.; Du, Y. C.; Liu, S.; Ji, Y. Y.; Yokoi, T.; Tatsumi, T.; Xiao, F. S.; Superhydrophobic Nanoporous Polymers as Efficient Adsorbents for Organic Compounds, Nano Today 2009, 4, 135–142. (42)Liu, F. J.; Huang, K.; Wu, Q.; Dai, S. Solvent‐free Self‐assembly to the Synthesis of Nitrogen‐doped Ordered Mesoporous Polymers for Highly Selective Capture and Conversion of CO2. Adv. Mater. 2017, 29, 1700445. 31



(43)Huang, K.; Liu, F. J.; Dai, S. Solvothermal Synthesis of Hierarchically Nanoporous Organic Polymers with Tunable Nitrogen Functionality for Highly Selective Capture of CO2. J. Mater. Chem. A. 2016, 4, 13063–13070. (44)Ji, G. P.; Yang, Z. Z.; Zhang, H. Y.; Zhao, Y. F.; Yu, B.; Ma, Z. S.; Liu, Z. M. Hierarchically Mesoporous o‐Hydroxyazobenzene Polymers: Synthesis and Their Applications in CO2 Capture and Conversion. Angew. Chem., Int. Ed. 2016, 55, 9685–9689. (45)Wang, X.; Deng, J. X.; Duan, X. J.; Liu, D.; Guo, J S.; Liu, P.; Crosslinked Polyaniline Nanorods with Improved Electrochemical Performance as Electrode Material for Supercapacitors. J. Mater. Chem. A, 2014, 2, 12323–12329. (46)Zeng, Y.; Zou, R.; Zhao, Y. Covalent Organic Frameworks for CO2 Capture. Adv. Mater. 2016, 28, 2855–2873. (47)Shen, L. J.; Lei, G. C.; Fang, Y. X.; Cao, Y. N.; Wang, X. C.; Jiang, L. L.; Polymeric Carbon Nitride Nanomesh as an Efficient and Durable Metal-free Catalyst for Oxidative Desulfurization. Chem. Commun. 2018, 54, 2475–2478. (48)Shen, L. J.; Wang, G. J.; Zheng, X. X.; Cao, Y. N.; Guo, Y. F.; Lin, K.; Jiang, L. L. Tuning the Growth of Cu-MOFs for Efficient Catalytic Hydrolysis of Carbonyl Sulfide. Chin. J. Catal. 2017, 38, 1373–1381.

32


Page 32 of 33

Page 33 of 33 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Table of Contents

33


Design of Efficient, Hierarchical Porous Polymers Endowed with

Recommend Documents