Guipeng Yu

1,3,5-Triazine-Based Microporous Polymers with Tunable Porosities for CO2 Capture and Fluorescent Sensing

Co-reporter:Shuai Gu, Jun Guo, Qiao Huang, Jianqiao He, Yu Fu, Guichao Kuang, Chunyue Pan, and Guipeng Yu

Macromolecules November 14, 2017 Volume 50(Issue 21) pp:8512-8512

Publication Date(Web):November 1, 2017

DOI:10.1021/acs.macromol.7b01857

The synthetic control over pore structure remains highly desirable for porous organic frameworks. Here, we present a competitive chemistry strategy, i.e., a systematical regulation on Friedel–Crafts reaction and Scholl coupling reaction through tuning the ratios of monomers. This leads to a series of spirobifluorene-based microporous polymers (Sbf-TMPs) with systematically tuned porosities and N content. Unlike the existing copolymerization strategy by which the synthesized polymers exhibit a monotonic change tendency in the porosities, our networks demonstrate an unusually different trend where the porosity increases first and then decreases with the increasing Ph/Cl ratios for the monomers. This is mainly ascribed to the completion of coexisting reaction routines and the different “internal molecular free volumes” of the repeating units. The as-made networks feature tunable capacities for CO2 adsorption over a wide range and attractive CO2/N2 selectivities. Moreover, these donor–acceptor type frameworks exhibit selective and highly sensitive fluorescence-on or fluorescence-off properties toward volatile organic compounds, which implies their great potential in fluorescent sensors.

Hyper-crosslinked aromatic polymers with improved microporosity for enhanced CO2/N2 and CO2/CH4 selectivity

Co-reporter:Dongyang Chen;Shuai Gu;Yu Fu;Xianbiao Fu;Yindong Zhang;Chunyue Pan

New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 14) pp:6834-6839

Publication Date(Web):2017/07/10

DOI:10.1039/C7NJ00919D

Hypercrosslinked polymers for selective CO2 capture have been successfully synthesized from highly rigid contorted blocks via a low-cost versatile strategy. Such amorphous materials with improved porosities achieve high specific surface areas of up to 1616 m2 g−1 and substantially improved pore volumes (1.53 cm3 g−1). The polymer networks feature hierarchically porous structures ranging from ultramicropores to mesopores (0.50 to 3.80 nm) as well as high physicochemical stability. They can uptake 15.9 wt% CO2 at 273 K/1 bar, surpassing nearly all polymers of intrinsic microporosity (PIMs) and most known hypercrosslinked polymers (HCPs). The abundant ultramicropores with pore diameters centered at around 0.50 nm allow selective CO2 uptake against N2 (ideal selectivity: 69.7) and CH4 (15.8). These results are significant for molecular design and emphasize the importance of utilizing rigid contorted blocks to build hierarchically porous networks for effective CO2 capture applications.

Acid/hydrazide-appended covalent triazine frameworks for low-pressure CO2 capture: pre-designable or post-synthesis modification

Co-reporter:Yu Fu;Zhiqiang Wang;Xianbiao Fu;Jun Yan;Cheng Liu;Chunyue Pan

Journal of Materials Chemistry A 2017 vol. 5(Issue 40) pp:21266-21274

Publication Date(Web):2017/10/17

DOI:10.1039/C7TA05416E

Pore surface engineering in nanoporous organic polymers (NOPs) targeted for their different applications remains a critical challenge. Here we compare two classic modification strategies, i.e. pre-designable and post-synthesis modification, which allow controlled loading of functionalities onto the pore wall by anchoring ethyl ester, acetic acid or acetohydrazides for effective CO2 capture. The pre-designed acetic acid-appended or acetohydrazide-appended precursors permit the construction of covalent triazine frameworks (CTF-CSU36@pre and CTF-CSU37@pre) with walls to which an exciting content of functional units is anchored. Conversely, channel functionalization is made possible by facile hydrolysis or hydrazide reaction of a carbazole-bridged triazine framework with pendant ethyl ester (CTF-CSU20) to produce surfaces with desired acetic acid (CTF-CSU36@post) or acetohydrazide groups (CTF-CSU37@post). High-degree dense integration of functional groups on the channel walls proved the superiority of the post-synthesis modification relative to the pre-designable strategy. Porous monoliths with high capacity at very low pressures (5.7 wt% at 273 K/0.15 bar), excellent IAST ideal selectivity (CO2/N2 = 145.9) and reusability were created, demonstrating their great potential for gas storage and separation. Significantly, such tailor-made pore-wall functional engineering could be a facile and powerful strategy for broad applications of NOPs.

BODIPY-based conjugated porous polymers for highly efficient volatile iodine capture

Co-reporter:Yunlong Zhu;Ya-Jian Ji;De-Gao Wang;Yi Zhang;Hui Tang;Xin-Ru Jia;Min Song;Gui-Chao Kuang

Journal of Materials Chemistry A 2017 vol. 5(Issue 14) pp:6622-6629

Publication Date(Web):2017/04/04

DOI:10.1039/C7TA00026J

Capturing volatile radionuclide iodine from nuclear and medical waste streams is an important environmental issue. In this work, we found that the 2,6-position hydrogen atoms of a BODIPY core undergo fast iodination with volatile iodine at room temperature. Inspired by our observation, two novel BODIPY-based conjugated porous polymers (CPPs) BDP-CPP-1 and BDP-CPP-2, and the reference compound NBDP-CPP, were prepared, which were designed and then synthesized via the Sonogashira cross-coupling reaction of 1,3,5-triethynyl-benzene (TEB) and dibromo-substituted derivatives. With the coexistence of the BODIPY units and plenty of triple bonds and phenyl rings that could adsorb iodine with high capacity and affinity, compounds BDP-CPP-1 and BDP-CPP-2 exhibited satisfactory iodine adsorption capacities of 2830 mg g−1 and 2230 mg g−1, respectively. Moreover, BDP-CPP-1 was shown to adsorb volatile iodine through a chemical mechanism involving the 2,6-position hydrogen atoms of the BODIPY core. Surprisingly, the active sites on the BODIPY units for a chemical iodination reaction were mostly eliminated as a result of the crosslinking of BODIPY units during the Sonogashira coupling reaction. The preliminary results demonstrated that the iodine uptake abilities, which are in the order of BDP-CPP-1 > BDP-CPP-2 > NBDP-CPP, are not only dependent on the surface area, but also on the BODIPY units. The BDP-CPPs show high thermal stability with a decomposition temperature of about 300 °C. In addition, the BDP-CPPs demonstrated remarkable recyclability. Due to the highly π-conjugated porous structure along with the high affinity for iodine molecules and iodination sites, some BODIPY-based CPPs may provide a feasible pathway to adsorb other volatile compounds.

Fabrication of conjugated microporous polytriazine nanotubes and nanospheres for highly selective CO2 capture

Co-reporter:Zhiqiang Wang;Junling Liu;Yu Fu;Cheng Liu;Chunyue Pan;Zhiyong Liu

Chemical Communications 2017 vol. 53(Issue 29) pp:4128-4131

Publication Date(Web):2017/04/06

DOI:10.1039/C7CC00704C

A one-spot template approach for fabricating porous organic nanotubes was developed and a molecular design, i.e. introducing thiophene and s-triazine functionalities to enhance host–guest interactions, lead to novel porous solids with high capacities for CO2 and exceptionally high ideal selectivities over N2 for effective gas storage and separation.

Facile Carbonization of Microporous Organic Polymers into Hierarchically Porous Carbons Targeted for Effective CO2 Uptake at Low Pressures

Co-reporter:Shuai Gu, Jianqiao He, Yunlong Zhu, Zhiqiang Wang, Dongyang Chen, Guipeng Yu, Chunyue Pan, Jianguo Guan, and Kai Tao

ACS Applied Materials & Interfaces 2016 Volume 8(Issue 28) pp:18383-18392

Publication Date(Web):June 22, 2016

DOI:10.1021/acsami.6b05170

The advent of microporous organic polymers (MOPs) has delivered great potential in gas storage and separation (CCS). However, the presence of only micropores in these polymers often imposes diffusion limitations, which has resulted in the low utilization of MOPs in CCS. Herein, facile chemical activation of the single microporous organic polymers (MOPs) resulted in a series of hierarchically porous carbons with hierarchically meso-microporous structures and high CO2 uptake capacities at low pressures. The MOPs precursors (termed as MOP-7–10) with a simple narrow micropore structure obtained in this work possess moderate apparent BET surface areas ranging from 479 to 819 m2 g–1. By comparing different activating agents for the carbonization of these MOPs matrials, we found the optimized carbon matrials MOPs-C activated by KOH show unique hierarchically porous structures with a significant expansion of dominant pore size from micropores to mesopores, whereas their microporosity is also significantly improved, which was evidenced by a significant increase in the micropore volume (from 0.27 to 0.68 cm3 g–1). This maybe related to the collapse and the structural rearrangement of the polymer farmeworks resulted from the activation of the activating agent KOH at high temperature. The as-made hierarchically porous carbons MOPs-C show an obvious increase in the BET surface area (from 819 to 1824 m2 g–1). And the unique hierarchically porous structures of MOPs-C significantly contributed to the enhancement of the CO2 capture capacities, which are up to 214 mg g–1 (at 273 K and 1 bar) and 52 mg g–1 (at 273 K and 0.15 bar), superior to those of the most known MOPs and porous carbons. The high physicochemical stabilities and appropriate isosteric adsorption heats as well as high CO2/N2 ideal selectivities endow these hierarchically porous carbon materials great potential in gas sorption and separation.

Tunable porosity of nanoporous organic polymers with hierarchical pores for enhanced CO2 capture

Co-reporter:Dongyang Chen, Shuai Gu, Yu Fu, Yunlong Zhu, Cheng Liu, Guanghui Li, Guipeng Yu and Chunyue Pan

Polymer Chemistry 2016 vol. 7(Issue 20) pp:3416-3422

Publication Date(Web):13 Apr 2016

DOI:10.1039/C6PY00278A

A series of cost-effective nanoporous organic polymers (NOP-50–NOP-52) with hierarchical pores for efficient CO2 capture were successfully synthesized via one-step Friedel–Crafts alkylation promoted by anhydrous FeCl3. Two chloromethyl monomers, i.e. dichloroxylene (DCX) and 4,4′-bis(chloromethyl)-1,1′-biphenyl (BCMBP) were utilized as crosslinkers to tailor the pore sizes. The porosity of the resultant polymers can be well-tuned by varying the length of crosslinkers and type of building blocks. More specifically, shorter linkers provide the polymers with greater microporosity, whereas longer linkers prove to block the microporosity created by the high-degree crosslinking of organic network. Introducing a series of highly rigid, nitrogen-containing, or metal-decorated building blocks features the obtained amorphous networks abundant microporosity and mesoporosity, and large Brunauer–Emmett–Teller (BET) surface areas up to 1650 m2 g−1 as measured by N2 adsorption at 77 K. Notably, such networks possess hierarchical pores with wide pore size distributions ranging from 0.55 to 4.3 nm. NOP-50A derived from DCX and carbazole exhibits competitive CO2 uptake up to 18.8 wt% at 273 K and 1 bar, surpassing most known HCPs. Remarkable selectivity ratios for CO2 adsorption over N2 (39–72) at 273 K and high CO2 isoteric heats of adsorption (34.2–46.7 kJ mol−1) were obtained. The high CO2/N2 selectivity and CO2 isosteric heat values could be ascribed to the good binding affinity of abundantly available electron-rich basic heteroatom or metal sites of the networks towards CO2. These results are significant for the construction of NOPs with hierarchical pores by introducing optimum building block and suitable length linkers for enhanced CO2 capture.

The role of the internal molecular free volume in defining organic porous copolymer properties: tunable porosity and highly selective CO2 adsorption

Co-reporter:Yindong Zhang, Yunlong Zhu, Jun Guo, Shuai Gu, Yuanyuan Wang, Yu Fu, Dongyang Chen, Yijun Lin, Guipeng Yu and Chunyue Pan

Physical Chemistry Chemical Physics 2016 vol. 18(Issue 16) pp:11323-11329

Publication Date(Web):17 Mar 2016

DOI:10.1039/C6CP00981F

A series of novel azo-functionalized copolymerized networks (simply known as NOP-34 series) with tunable permanent microporosity and highly selective carbon dioxide capture are disclosed. The synthesis was accomplished by Zn-induced reductive cross-coupling copolymerization of two nitrobenzene-like building blocks with different ‘internal molecular free volumes’ (IMFVs), i.e., 2,7,14-trinitrotriptycene and 2,2′,7,7′-tetranitro-9,9′-spirobifluorene, with different molar ratios. Increasing the content of spirobifluorene (SBF) segments with a smaller IMFV relative to that of triptycene leads to an unconventional rise–fall pattern in porosity. Unlike most reported porous copolymers whose surface area lies between the corresponding homopolymers, the copolymer NOP-34@7030 with 30% SBF segments unprecedentedly shows the largest Brunauer–Emmett–Teller specific surface area (up to 823 m2 g−1) as well as promoted CO2 uptake abilities (from 2.31 to 3.22 mmol g−1, at 273 K/1.0 bar). The 100% triptycene(TPC)-derived homopolymer (NOP-34@1000) with a moderate surface area shows the highest CO2/N2 IAST selectivity of 109 (273 K) among the five samples, surpassing most known nanoporous organic polymers. This may contribute significantly to our understanding of the relationship of IMFVs with the properties of copolymerized materials.

Nanoscale porous triazine-based frameworks with cyanate ester linkages for efficient drug delivery

Co-reporter:Junling Liu, Yu Fu, Xianbo Fu, Yuxin Li, Dongke Liang, Yuan Song, Chunyue Pan, Guipeng Yu and Xuxian Xiao

RSC Advances 2016 vol. 6(Issue 25) pp:20834-20842

Publication Date(Web):16 Feb 2016

DOI:10.1039/C6RA01044J

A novel set of nanoporous organic polytriazines with cyanate ester linkages, termed the NOP-14 series, have been designed and constructed from a new triangular monomer 2,4,6-tris(4-cyanatophenyl)-1,3,5-triazine. Four different concentrations of reactive groups in the same solvent medium, have been employed to allow an easy modulation of pore size. The cyanate ester-bridged networks demonstrates somewhat acceptable biocompatibility as identified by cell viability assays with HeLa cells using an MTT assay, and were used as new matrices for in vitro drug delivery of a model drug ibuprofen (IBU). This kind of nanoscale solid with limited surface areas ranging from 25 to 144 m2 g−1, however, can adsorb around 54 wt% of IBU (IBU/NOP-14 mass ratio 2:1, immersion time 24 h), demonstrating that the amount of inserted drug does not depend on the surface areas, but correlates more closely with the pore structure. The release behavior of IBU, depending on the porosities and structure of NOP-14 for host–drug interactions, is even better than that of its analogous PAF-6 as well as MCM-41. This study offers the possibility to facilely engineer pore structures through optimization of reaction conditions to control in vivo fate and also extends the controlled release of drugs to general polymers.

Photovoltaic performance of long-chain poly(triphenylamine-phenothiazine) dyes with a tunable π-bridge for dye-sensitized solar cells

Co-reporter:Gang Wang, Yingying Wu, Wenhui Ding, Guipeng Yu, Zhubing Hu, Haizhen Wang, Suqin Liu, Yingping Zou and Chunyue Pan

Journal of Materials Chemistry A 2015 vol. 3(Issue 27) pp:14217-14227

Publication Date(Web):01 Jun 2015

DOI:10.1039/C5TA03425F

A set of conjugated polymers based on poly(triphenylamine-phenothiazine) with carboxylic acid side groups have been synthesized and utilized as sensitizers for dye-sensitized solar cells (DSSCs). The polymers feature a conjugated side-chain consisting of a thiophene unit (PPAT4), alternating with either 3,4-ethylenedioxythiophene (EDOT, PPAT5) or EDOT–thiophene (PPAT6) as the π-bridge. This methodology constitutes a consolidated step to adjust the molecular HOMO and LUMO energy levels of dyes, hence red-shifting and broadening the absorption spectra of a conjugated polymer. Compared with the model compound (PAT), the polymers exhibit a higher molar extinction coefficient throughout the visible region, and a better photovoltaic performance in DSSCs with I−/I3− electrolyte. Interestingly, depending on the Suzuki coupling reaction, we obtain a fairly high degree of polymerization (DP values are 58, 46, and 38 for PPAT4, PPAT5 and PPAT6, respectively) based on the three polymers. More encouraging is that when using the high DP polymers as sensitizers, photoelectrochemical tests based on the DSSC format demonstrate a power conversion efficiency of 4.7%, 3.7% and 4.1% for PPAT4, PPAT5 and PPAT6, respectively, under the illumination of AM1.5G and 100 mW cm−2. This presented a considerably high photo-to-electric conversion efficiency in polymer dye-sensitized solar cells, outperforming all polymer dye-sensitized solar cells previously reported.

A rational construction of microporous imide-bridged covalent–organic polytriazines for high-enthalpy small gas absorption

Co-reporter:Shaofei Wu, Shuai Gu, Aiqing Zhang, Guipeng Yu, Zhonggang Wang, Jigao Jian and Chunyue Pan

Journal of Materials Chemistry A 2015 vol. 3(Issue 2) pp:878-885

Publication Date(Web):04 Nov 2014

DOI:10.1039/C4TA04734F

A series of microporous imide functionalized 1,3,5-triazine frameworks (named TPIs@IC) were designed by an easy-construction technology other than the known imidization method for the construction of porous triazine-based polyimide networks (TPIs) with the same chemical compositions. In contrast to TPIs, TPIs@IC exhibit much higher Brunauer–Emmett–Teller (BET) surface areas (up to 1053 m2 g−1) and carbon dioxide uptake (up to 3.2 mmol g−1/14.2 wt% at 273 K/1 bar). The presence of abundant ultramicropores at 5.4–6.8 Å, mainly ascribed to a high-level cyano cross-linking, allows the high heat absorption and high selective capture of CO2. The Qst (CO2 esoteric enthalpies) from their CO2 adsorption isotherms at 273 and 298 K are calculated to be in the range 46.1–49.3 kJ mol−1 at low CO2 loading, and the ideal CO2/N2 separation factors are up to 151, exceeding those of the most reported porous organic polymers to date. High storage capacities of TPIs@IC for other small gases like CH4 (5.01 wt% at 298 K/22 bar) and H2 (1.47 wt% at 77 K/1 bar) were also observed, making them promising adsorbents for gas adsorption and separation.

A Luminescent Hypercrosslinked Conjugated Microporous Polymer for Efficient Removal and Detection of Mercury Ions

Co-reporter:Lu Xiang;Yunlong Zhu;Shuai Gu;Dongyang Chen;Xian Fu;Yindong Zhang;Chunyue Pan;Yuehua Hu

Macromolecular Rapid Communications 2015 Volume 36( Issue 17) pp:1566-1571

Publication Date(Web):

DOI:10.1002/marc.201500159

Use thiophene as a comonomer alternative to triphenylamine combine with 4, 8-dithienylbenzo [1,2-b: 4, 5-b'] dithiophene as a polymer dye in sensitized solar cells

Co-reporter:Gang Wang, Wenhui Ding, Haizhen Wang, Xianyong Zhou, Guipeng Yu, Chunyue Pan

Synthetic Metals 2015 Volume 209() pp:119-127

Publication Date(Web):November 2015

DOI:10.1016/j.synthmet.2015.07.002

•Synthesized two new 4, 8-dithienylbenzo dithiophene based polymers.•The two polymers were successfully used as dyes for DSSCs.•The polymer based on triphenylamine has higher absorption ability and IPCE peak.•The simplified polymer (PPTB8) has higher Jsc and power conversion efficiency.Triphenylamine (TPA) and its derivatives are well-known pigments with excellent electron donating abilities and chemical, thermal and photochemical stabilities, and have been used in various optical and electronic fields. In this context, the polymer PPAB7 containing a TPA and a 4, 8-dithienylbenzo [1,2-b: 4, 5-b'] dithiophene (BDT) as the donor group in the main chain and a cyanoacetic acid accepter in the side chain, linked by a thiophene unit is synthesized. To study the influence of donor in the backbone, we crop out the TPA and use the linker thiophene unit as a comonomer directly then a new polymer PPTB8 is synthesized. Combining a mesoporous titania film grafted by these two simple polymer dye with I−/I3− redox couple, the none TPA sensitizer PPTB8 based DSSC obtained higher power conversion efficiency (PCE) of 3.78% than PPAB7 of 2.21% with a degree of polymerization (DP) of ∼5 and ∼6, respectively, at an irradiance of the AM 1.5 G sunlight. To understand the improvement performance of PPTB8, theoretical calculations, absorption-emission spectra, electrochemistry, infrared spectroscopy and photovoltaic measurements are used to compare the photophysics, interfacial and photovoltaic property of the two polymers. The results suggest that the increased photovoltaic property of the simplified structure (PPTB8) is due to its broader spectra and higher efficient electron injection property resulting in higher short current.

Conductance investigation of p-MIECs fabricated by poly(3,4-ethylenedioxy thiophene), polyacrylic acid, polyethylene oxide, and lithium-ion salt

Co-reporter:Huihui Xu;Jidi Cui;Chunyue Pan;Shiyu Hong;Xipeng Wang;Zhijiang Yao

Polymer Composites 2015 Volume 36( Issue 11) pp:2076-2083

Publication Date(Web):

DOI:10.1002/pc.23118

Polymer blends and composite films were facilely prepared from their aqueous solutions with varying contents of poly(3,4-ethylenedioxythiophene) (PEDOT), polyethylene oxide (PEO), and polyacrylic acid (PAA). The physicochemical and electric properties of the composite films were analyzed by Raman spectra, infrared spectra (FT-IR), scanning electronic microscopy (SEM), thermogravimetric analysis (TGA), and four-point probe method. PEDOT was successfully incorporated into each blend which was confirmed by spectra analysis. The crystallization of PAA or PEO and the structure of PEDOT should be taken into consideration for the electronic conductivity. According to Raman spectra, in the case of PEDOT–PAA–PEO, conformation of the PEDOT backbone changed from the quinoid to the benzoid structure partly. The ionic conductivities of lithium-ion salt-mixed PAA–PEO and ternary blend were characterized by AC impedance spectroscopy. The ternary blend with LiCoO₂ presents good electronic and ionic conductivity, and it appears to be a new candidate for polymeric mixed ionic electronic conductor. POLYM. COMPOS., 36:2076–2083, 2015. © 2014 Society of Plastics Engineer

Metal Microporous Aromatic Polymers with Improved Performance for Small Gas Storage

Co-reporter:Xian Fu;Yindong Zhang;Shuai Gu;Yunlong Zhu; Guipeng Yu;Chunyue Pan; Zhonggang Wang;Yuehua Hu

Chemistry - A European Journal 2015 Volume 21( Issue 38) pp:13357-13363

Publication Date(Web):

DOI:10.1002/chem.201501594

Abstract

A novel metal-doping strategy was developed for the construction of iron-decorated microporous aromatic polymers with high small-gas-uptake capacities. Cost-effective ferrocene-functionalized microporous aromatic polymers (FMAPs) were constructed by a one-step Friedel–Crafts reaction of ferrocene and s-triazine monomers. The introduction of ferrocene endows the microporous polymers with a regular and homogenous dispersion of iron, which avoids the slow reunion that is usually encountered in previously reported metal-doping procedures, permitting a strong interaction between the porous solid and guest gases. Compared to ferrocene-free analogues, FMAP-1, which has a moderate BET surface area, shows good gas-adsorption capabilities for H₂ (1.75 wt % at 77 K/1.0 bar), CH₄ (5.5 wt % at 298 K/25.0 bar), and CO₂ (16.9 wt % at 273 K/1.0 bar), as well as a remarkably high ideal adsorbed solution theory CO₂/N₂ selectivity (107 v/v at 273 K/(0–1.0) bar), and high isosteric heats of adsorption of H₂ (16.9 kJ mol⁻¹) and CO₂ (41.6 kJ mol⁻¹).

Liquid acid-catalysed fabrication of nanoporous 1,3,5-triazine frameworks with efficient and selective CO2 uptake

Co-reporter:Shaohui Xiong, Xian Fu, Lu Xiang, Guipeng Yu, Jianguo Guan, Zhonggang Wang, Yong Du, Xiang Xiong and Chunyue Pan

Polymer Chemistry 2014 vol. 5(Issue 10) pp:3424-3431

Publication Date(Web):24 Jan 2014

DOI:10.1039/C3PY01471A

New classes of nanoporous organic polymers based on 1,3,5-triazine units (NOP-1–6) were synthesized via a straightforward, methane-sulfonic acid-catalysed, cost-effective Friedel–Crafts reaction of 2,4,6-trichloro-1,3,5-triazine and tetrahedral building blocks. Among them, NOP-3 with a Brunauer–Emmet–Teller (BET) specific surface area up to 894 m2 g−1 and the total volume exceeding 0.41 m3 g−1 exhibits good hydrogen adsorption capacity (up to 1.14 wt% at 77 K/1.0 bar) and high carbon dioxide uptake (up to 11.03 wt% at 273 K/1.0 bar). Furthermore, it presents an effective selectivity for CO2 adsorption (NOP-6, CO2/N2 selectivity 38.7 at 273 K/1.0 bar), demonstrating potential applications in gas adsorption and separation.

A comparative study on properties of two phenoxazine-based dyes for dye-sensitized solar cells

Co-reporter:Haijun Tan, Chunyue Pan, Gang Wang, Yingying Wu, Yiping Zhang, Guipeng Yu, Min Zhang

Dyes and Pigments 2014 Volume 101() pp:67-73

Publication Date(Web):February 2014

DOI:10.1016/j.dyepig.2013.09.039

•Two phenoxazine-based dyes have been synthesized for a comparatively study.•The result shows that POZ-2 exhibited higher η of 6.5% than POZ-1 (η = 2.4%).•Conjugated direction is the crucial influential factor of η.Two phenoxazine (POZ)-based organic D–π–A sensitizers (POZ-1 and POZ-2) were synthesized. Then these two dyes were applied in dye-sensitized solar cells (DSSCs) to investigate the influence of different conjugated direction, extra phenyl ring and alkyl chain on the light-harvesting, energy level and photovoltaic properties through a joint spectral, electrochemical and photovoltaic study. The result shows that dye POZ-2 exhibits higher power conversion efficiency (η = 6.5%) than dye POZ-1 (η = 2.4%) under standard illumination (Global Air Mass 1.5). Besides, the geometries of the dyes were optimized to gain insight into the molecular structure and electron distribution. The charge extraction and transient photovoltage decay measurements were further performed to understand the alterative order of efficiency.Two phenoxazine-based organic (POZ-1, POZ-2) dyes were synthesized for a comparatively study.

Series of D-π-A system based on isoindigo dyes for DSSC: Synthesis, electrochemical and photovoltaic properties

Co-reporter:Wang Gang, Tan Haijun, Zhang Yiping, Wu Yingying, Hu Zhubin, Yu Guipeng, Pan Chunyue

Synthetic Metals 2014 Volume 187() pp:17-23

Publication Date(Web):January 2014

DOI:10.1016/j.synthmet.2013.09.039

•We synthesized three isoindigo based organic dyes (ID1, ID2, ID3).•ID1 shows higher energy conversion efficiency (3.33%).•Double anchor group could affect the progress of electron directional transmission.Novel D-π-A system organic dyes (ID1, ID2 and ID3) based on isoindigo (ID), which contain triphenylamine (ID1) or isoindigo (ID2 and ID3) as electron donors, isoindigo and thiophene as a π-conjugated system and a cyanoacrylic acid moiety as an electron acceptor and anchoring group, have been then synthesized and characterized by 1H NMR, UV–vis, CV. Dye-sensitized solar cells (DSSCs) based on these dyes were also fabricated and tested. As the photovoltaic performance tests demonstrated, the ID1 exhibits broader absorption spectra, higher maximum incident photon-to-current conversion efficiency (IPCE) and maximum photon-to-electron conversion efficiency (η) of 3.33% under 100 mW/cm2 simulated AM 1.5G solar irradiation.

Facile Preparation of Dibenzoheterocycle-Functional Nanoporous Polymeric Networks with High Gas Uptake Capacities

Co-reporter:Shaofei Wu, Yao Liu, Guipeng Yu, Jianguo Guan, Chunyue Pan, Yong Du, Xiang Xiong, and Zhonggang Wang

Macromolecules 2014 Volume 47(Issue 9) pp:2875-2882

Publication Date(Web):May 2, 2014

DOI:10.1021/ma500080s

A consolidated ionothermal strategy was developed for the polymerization of thermally unstable nitriles to construct high performance materials with permanent porosity, and carbazole, dibenzofuran, and dibenzothiophene were separately introduced into covalent triazine-based networks to investigate the effects of heterocycles on the gas adsorption performance. Three nitriles, namely 3,6-dicyanocarbazole, 3,6-dicyanodibenzofuran, and 3,6-dicyanodibenzothiophene, were designed and synthesized, which were readily converted to heat-resistant intermediates at a moderate temperature and then polymerized to create highly porous poly(triazine) networks instead of the traditional one-step procedure. This documents an improved strategy for the successful construction of heterocyclic-functional triazine-based materials. The chemical structures of monomers and polymers were confirmed by 1H NMR, FTIR, and elemental analysis. Such polymers with high physical–chemical stability and comparable BET surface areas can uptake 1.44 wt % H2 at 77 K/1 bar and 14.0 wt % CO2 at 273 K/1 bar and present a high selectivity for gas adsorption of CO2 (CO2/N2 ideal selectivity up to 45 at 273K/1.0 bar). The nitrogen- and oxygen-rich characteristics of carbazole and dibenzofuran feature the networks strong affinity for CO2 and thereby high CO2 adsorption capacity. This also helps to thoroughly understand the influence of pore structure and chemical composition on the adsorption properties of small gas molecules.

Phenoxazine-based organic dyes with different chromophores for dye-sensitized solar cells

Co-reporter:Haijun Tan, Chunyue Pan, Gang Wang, Yingying Wu, Yiping Zhang, Yingping Zou, Guipeng Yu, Min Zhang

Organic Electronics 2013 Volume 14(Issue 11) pp:2795-2801

Publication Date(Web):November 2013

DOI:10.1016/j.orgel.2013.07.008

•We have synthesized four phenoxazine-based dyes (POZ-2, POZ-3, POZ-4, POZ-5).•The POZ-3 cell shows the highest η of 7.8%.•The electron donors are the main factor affecting the performance of these cells.A series of organic dyes (POZ-2, POZ-3, POZ-4 and POZ-5) involving phenoxazine were synthesized as sensitizers for application in dye-sensitized solar cells (DSSCs). For comparison, three different electron donors namely 10-phenyl-10H-phe-nothiazine, 10-phenyl-10H-phenoxazine and triphenylamine were separately appended onto the 7-position of the model dye (POZ-2). The obtained four dyes exhibit considerably high values of conversion efficiencies of 6.6%, 7.8%, 7.1% and 6.4%, respectively, under the simulated AM1.5G conditions. The geometries of the dyes were optimized to gain insight into the molecular structure and electron distribution, and then the charge extraction and transient photovoltage decay measurements were further performed to understand the influence of electron donors on the photovoltaic behaviors.A series of phnoxazine dyes containing different chromophores were synthesized as sensitizers for application in dye-sensitized solar cells

Novel thermally stable and organosoluble aromatic polyamides with main chain phenyl-1,3,5-triazine moieties

Co-reporter:Guipeng Yu, Bin Li, Junling Liu, Shaofei Wu, Haijun Tan, Chunyue Pan, Xigao Jian

Polymer Degradation and Stability 2012 Volume 97(Issue 9) pp:1807-1814

Publication Date(Web):September 2012

DOI:10.1016/j.polymdegradstab.2012.05.040

The syntheses and properties of phenyl-1,3,5-triazine functional aromatic polyamides are described. From 2,4,6-trichloro-1,3,5-triazine (1), an aromatic diacid, namely 4-(4,6-diphenyl-1,3,5-triazin-2-yl)benzoic acid (6), was prepared by a three-step reaction in satisfactory yields. A model reaction of 6 with aniline (7) was carried out to determine feasibility of amidization. Aromatic poly(phenyl-1,3,5-triazine amide)s (10a–10e) with inherent viscosities ranging from 0.28 to 1.26 dL/g were synthesized from Yamazaki phosphorylation polycondensation of 6 with aromatic diamines (9a–9e). The reactions were conducted in N-methyl-2-pyrrolidone (NMP) to yield high-molecular-weight amorphous polymers in essentially high yields. All polymers are readily soluble in NMP and N,N-dimethylacetamide (DMAc) at room temperature, and formed transparent films from their solution. The films exhibit good mechanical properties with tensile strengths of 71.5–94.7 MPa, elongations at break of 6.1–10.0%, and initial moduli of 2.3–2.8 GPa except that of 10a is slightly brittle. These polymers have high glass transitions from 311 to 330 °C, depending on the aromatic diamines used in the polycondensation, and they demonstrate excellent thermal stabilities in excess of 440 °C (5% weight loss in air). Isothermal TGA measurements reveal that the obtained benzene-1,3-diamine-based poly(phenyl-1,3,5-triazine amide) (10b) belongs to the most superior class of heat resistant polymers such as polyamide Kevlar®.

Effects of phenyl-s-triazine moieties on thermal stability and degradation behavior of aromatic polyether sulfones

Co-reporter:Guipeng Yu;Cheng Liu;Bing Li;Liwei Wang;Jinyan Wang

Journal of Polymer Research 2012 Volume 19( Issue 3) pp:

Publication Date(Web):2012 March

DOI:10.1007/s10965-012-9829-1

The effect of the incorporation of phenyl-s-triazine units into the main chain of phthalazinone-based polyether sulfones on initial decomposition temperature, activation energy, thermal-mechanical property and possible degradation mechanism has been investigated. To this purpose, decomposition of poly(phthalazinone ether sulfone phenyl-s-triazine) copolymers (PPESPs) of different monomer compositions have been studied by utilizing thermogravimetry and differential scanning calorimetry. Non-isothermal experiments under nitrogen were performed, and the apparent activation energy (Ea) was calculated by isoconversional and conversional methods including the methods of Flynn-Wall-Ozawa, Friedman and Kissinger. In the conversion range (5–30%) studied, solid-state decomposition process of PPESPs is found to be a mechanism involving phase boundary controlled reaction (Ea: 189–201 kJ mol−1) except that phenyl-s-triazine-rich copolymers exhibit a mechanism involving three-dimensional diffusion (Ea: 196–225 kJ mol−1) in terms of Coats–Redfern method. The phenyl-s-triazine-rich copolymers display much higher Ea and slighter mechanical property-change compared to sulfone-rich copolymers and generic aromatic polyether sulfone, suggesting strong stabilizing effect of the phenyl-s-triazine moieties.

BODIPY-based conjugated porous polymers for highly efficient volatile iodine capture

Co-reporter:Yunlong Zhu, Ya-Jian Ji, De-Gao Wang, Yi Zhang, Hui Tang, Xin-Ru Jia, Min Song, Guipeng Yu and Gui-Chao Kuang

Journal of Materials Chemistry A 2017 - vol. 5(Issue 14) pp:NaN6629-6629

Publication Date(Web):2017/03/09

DOI:10.1039/C7TA00026J

Capturing volatile radionuclide iodine from nuclear and medical waste streams is an important environmental issue. In this work, we found that the 2,6-position hydrogen atoms of a BODIPY core undergo fast iodination with volatile iodine at room temperature. Inspired by our observation, two novel BODIPY-based conjugated porous polymers (CPPs) BDP-CPP-1 and BDP-CPP-2, and the reference compound NBDP-CPP, were prepared, which were designed and then synthesized via the Sonogashira cross-coupling reaction of 1,3,5-triethynyl-benzene (TEB) and dibromo-substituted derivatives. With the coexistence of the BODIPY units and plenty of triple bonds and phenyl rings that could adsorb iodine with high capacity and affinity, compounds BDP-CPP-1 and BDP-CPP-2 exhibited satisfactory iodine adsorption capacities of 2830 mg g−1 and 2230 mg g−1, respectively. Moreover, BDP-CPP-1 was shown to adsorb volatile iodine through a chemical mechanism involving the 2,6-position hydrogen atoms of the BODIPY core. Surprisingly, the active sites on the BODIPY units for a chemical iodination reaction were mostly eliminated as a result of the crosslinking of BODIPY units during the Sonogashira coupling reaction. The preliminary results demonstrated that the iodine uptake abilities, which are in the order of BDP-CPP-1 > BDP-CPP-2 > NBDP-CPP, are not only dependent on the surface area, but also on the BODIPY units. The BDP-CPPs show high thermal stability with a decomposition temperature of about 300 °C. In addition, the BDP-CPPs demonstrated remarkable recyclability. Due to the highly π-conjugated porous structure along with the high affinity for iodine molecules and iodination sites, some BODIPY-based CPPs may provide a feasible pathway to adsorb other volatile compounds.

The role of the internal molecular free volume in defining organic porous copolymer properties: tunable porosity and highly selective CO2 adsorption

Co-reporter:Yindong Zhang, Yunlong Zhu, Jun Guo, Shuai Gu, Yuanyuan Wang, Yu Fu, Dongyang Chen, Yijun Lin, Guipeng Yu and Chunyue Pan

Physical Chemistry Chemical Physics 2016 - vol. 18(Issue 16) pp:NaN11329-11329

Publication Date(Web):2016/03/17

DOI:10.1039/C6CP00981F

A series of novel azo-functionalized copolymerized networks (simply known as NOP-34 series) with tunable permanent microporosity and highly selective carbon dioxide capture are disclosed. The synthesis was accomplished by Zn-induced reductive cross-coupling copolymerization of two nitrobenzene-like building blocks with different ‘internal molecular free volumes’ (IMFVs), i.e., 2,7,14-trinitrotriptycene and 2,2′,7,7′-tetranitro-9,9′-spirobifluorene, with different molar ratios. Increasing the content of spirobifluorene (SBF) segments with a smaller IMFV relative to that of triptycene leads to an unconventional rise–fall pattern in porosity. Unlike most reported porous copolymers whose surface area lies between the corresponding homopolymers, the copolymer NOP-34@7030 with 30% SBF segments unprecedentedly shows the largest Brunauer–Emmett–Teller specific surface area (up to 823 m2 g−1) as well as promoted CO2 uptake abilities (from 2.31 to 3.22 mmol g−1, at 273 K/1.0 bar). The 100% triptycene(TPC)-derived homopolymer (NOP-34@1000) with a moderate surface area shows the highest CO2/N2 IAST selectivity of 109 (273 K) among the five samples, surpassing most known nanoporous organic polymers. This may contribute significantly to our understanding of the relationship of IMFVs with the properties of copolymerized materials.

Photovoltaic performance of long-chain poly(triphenylamine-phenothiazine) dyes with a tunable π-bridge for dye-sensitized solar cells

Co-reporter:Gang Wang, Yingying Wu, Wenhui Ding, Guipeng Yu, Zhubing Hu, Haizhen Wang, Suqin Liu, Yingping Zou and Chunyue Pan

Journal of Materials Chemistry A 2015 - vol. 3(Issue 27) pp:NaN14227-14227

Publication Date(Web):2015/06/01

DOI:10.1039/C5TA03425F

A set of conjugated polymers based on poly(triphenylamine-phenothiazine) with carboxylic acid side groups have been synthesized and utilized as sensitizers for dye-sensitized solar cells (DSSCs). The polymers feature a conjugated side-chain consisting of a thiophene unit (PPAT4), alternating with either 3,4-ethylenedioxythiophene (EDOT, PPAT5) or EDOT–thiophene (PPAT6) as the π-bridge. This methodology constitutes a consolidated step to adjust the molecular HOMO and LUMO energy levels of dyes, hence red-shifting and broadening the absorption spectra of a conjugated polymer. Compared with the model compound (PAT), the polymers exhibit a higher molar extinction coefficient throughout the visible region, and a better photovoltaic performance in DSSCs with I−/I3− electrolyte. Interestingly, depending on the Suzuki coupling reaction, we obtain a fairly high degree of polymerization (DP values are 58, 46, and 38 for PPAT4, PPAT5 and PPAT6, respectively) based on the three polymers. More encouraging is that when using the high DP polymers as sensitizers, photoelectrochemical tests based on the DSSC format demonstrate a power conversion efficiency of 4.7%, 3.7% and 4.1% for PPAT4, PPAT5 and PPAT6, respectively, under the illumination of AM1.5G and 100 mW cm−2. This presented a considerably high photo-to-electric conversion efficiency in polymer dye-sensitized solar cells, outperforming all polymer dye-sensitized solar cells previously reported.

A rational construction of microporous imide-bridged covalent–organic polytriazines for high-enthalpy small gas absorption

Co-reporter:Shaofei Wu, Shuai Gu, Aiqing Zhang, Guipeng Yu, Zhonggang Wang, Jigao Jian and Chunyue Pan

Journal of Materials Chemistry A 2015 - vol. 3(Issue 2) pp:NaN885-885

Publication Date(Web):2014/11/04

DOI:10.1039/C4TA04734F

A series of microporous imide functionalized 1,3,5-triazine frameworks (named TPIs@IC) were designed by an easy-construction technology other than the known imidization method for the construction of porous triazine-based polyimide networks (TPIs) with the same chemical compositions. In contrast to TPIs, TPIs@IC exhibit much higher Brunauer–Emmett–Teller (BET) surface areas (up to 1053 m2 g−1) and carbon dioxide uptake (up to 3.2 mmol g−1/14.2 wt% at 273 K/1 bar). The presence of abundant ultramicropores at 5.4–6.8 Å, mainly ascribed to a high-level cyano cross-linking, allows the high heat absorption and high selective capture of CO2. The Qst (CO2 esoteric enthalpies) from their CO2 adsorption isotherms at 273 and 298 K are calculated to be in the range 46.1–49.3 kJ mol−1 at low CO2 loading, and the ideal CO2/N2 separation factors are up to 151, exceeding those of the most reported porous organic polymers to date. High storage capacities of TPIs@IC for other small gases like CH4 (5.01 wt% at 298 K/22 bar) and H2 (1.47 wt% at 77 K/1 bar) were also observed, making them promising adsorbents for gas adsorption and separation.

Fabrication of conjugated microporous polytriazine nanotubes and nanospheres for highly selective CO2 capture

Co-reporter:Zhiqiang Wang, Junling Liu, Yu Fu, Cheng Liu, Chunyue Pan, Zhiyong Liu and Guipeng Yu

Chemical Communications 2017 - vol. 53(Issue 29) pp:NaN4131-4131

Publication Date(Web):2017/03/21

DOI:10.1039/C7CC00704C

A one-spot template approach for fabricating porous organic nanotubes was developed and a molecular design, i.e. introducing thiophene and s-triazine functionalities to enhance host–guest interactions, lead to novel porous solids with high capacities for CO2 and exceptionally high ideal selectivities over N2 for effective gas storage and separation.

TOPICS

Abstract