JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Yuan Li,Biao Pei,Junjie Chen,Shaosuo Bing,Linxiao Hou,Qi Sun,Gang Xu,Zhikan Yao,Lin Zhang
A novel catalyst with a yolk-shell structure was designed to overcome the leaching of noble metals in heterogeneous catalysis. Through a template method, palladium (Pd) nanoparticles were encapsulated by hollow spherical covalent organic frameworks (COFs) consisting of 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde (Tp) and p-phenylenediamine (Pa). The final catalyst with a yolk-shell structure was denoted as (Pd/C)@TpPa COFs. The unique morphology and chemical structure of this novel composite (Pd/C)@TpPa COFs were confirmed by a transmission electron microscope (TEM), a laser particle analyzer, X-ray diffraction (XRD), and N 2 adsorption and desorption. Subsequently, to demonstrate its catalytic performance brought by structural design, this novel catalyst was applied to catalyze the Suzuki reaction . Interestingly, this catalyst exhibited a brilliant size cutoff efficiency for aryl benzene amounting to 100% and achieved a high conversion with only 0.05 mol% Pd loading. Besides, this catalyst could be readily recovered via filtration and reused for at least five consecutive cycles without any significant loss in its activity.
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高影响因子
JOURNAL OF CHEMICAL SCIENCES
·
2020
·Vol. 132
·期 1
·1-9
·
IF 1.406
Zhong Shaofeng
Abstract Homogeneous chitosan/poly(methacrylic acid) solution containing Pd 2+ cations was successfully prepared by addition of pyridine-2-carboxaldehyde. Then, this homogeneous solution was smoothly electrospun into uniform composite nanofibers with mean diameter of 442 ± 163 nm, followed by annealing at elevated temperature to improve the solvent resistance. Scanning electron microscopy (SEM) analysis shows that the solvent resistance of the composite nanofibers was improved with the increment of annealing temperature. FT-IR spectra demonstrate that the chemical structure of the composite nanofibers was not oxidized after annealing process. Moreover, the palladium species were homogeneously incorporated inside the composite nanofibers. The catalytic performance of these novel composite nanofibers was evaluated by Heck reaction. The catalysis result shows that these composite nanofibers were very efficient to catalyze the Heck reaction of aromatic iodides with acrylates with yields over 86%. Moreover, these composite nanofibers can be reused for 10 times with little decrement of yield. Graphic abstract A novel palladium embedded chitosan composite nanofiber mat has been prepared by electrospinning and thermal techniques. This novel fiber palladium catalyst exhibited high catalytic activity and stability for Heck reaction.
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APPLIED ORGANOMETALLIC CHEMISTRY
·
2020
·Vol. 34
·期 5
·e5619
·
IF 3.14
Yijun Du,Sailong Wei,Minchao Tang,Miaoting Ye,Hongyu Tao,Chenze Qi,Linjun Shao
Palladium chloride doped chitosan composite nanofibers were prepared by electrospinning with sodium polyacrylate (PAAS) as the co-spinning agent. The composite nanofibers are subsequently treated at elevated temperature to improve their solvent resistance. The Pd (II) cations inside the composite nanofibers were reduced into uniform palladium nanoparticles (Pd NPs) with mean diameter of ~4.93 nm. These Pd NPs inside the chitosan composite nanofibers exhibited excellent catalytic activity for Heck reactions of aromatic iodides with alkenes with yields over 85%. Moreover, due to the fibrous structure, this novel fibrous palladium catalyst could be readily recovered by simple filtration and reused for 18 times without loss of initial catalytic activity. It was found that the reactants could readily diffuse from the reaction solution to the active Pd NPs inside the nanofibers and the products could departure from composite fibers into the reaction solution, while the Pd NPs were tightly restricted inside the chitosan composite nanofibers.
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CARBON
·
2020
·
IF 8.821
Kunlin Liu,Jiuzhou Wang,Ting Yang,Hong Wang,Chengyang Wang,Mingming Chen
Traditional synthesis methods of mesoporous carbon include hard templates (e.g., metal oxides , metal salts and mesoporous silica) and soft templates (e.g., surfactant and block copolymer). However, complicated and time-consuming procedures, high template costs, and harsh preparation conditions hinder the scale-up of these methods. Here, we report a simple and bottom-up strategy to synthesize mesoporous carbon by using the sodium-assisted carbonization of bromobenzene without additional templates added. Depending on the pyrolysis temperature, the obtained material with nanorod structures has a high surface area of 1902 m 2 g −1 , a large pore volume of 1.21 cm 3 g −1 and a high degree of graphitization . Meanwhile, the pore-forming mechanism of this strategy is explored and attributed to the “ in situ templating” effect of NaBr. The resultant material at 800 °C shows considerable rate performance, long lifetime and high power density. Additionally, the versatility and feasibility of the technique are validated via carbonization of six halogenated aromatic hydrocarbons by three alkali metals . Compared with lithium and potassium , sodium has better pore-forming effect and the obtained products possess a high surface area (1450–2100 m 2 g −1 ) and a large pore volume (1.1–1.6 cm 3 g −1 ). Furthermore, these mesoporous carbons show high adsorption capacity on dye macromolecules.
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JOURNAL OF APPLIED POLYMER SCIENCE
·
2020
·Vol. 138
·期 2
·49666
·
IF 2.52
Benben Zhang,Zeyu Ye,Min Qin,Qingqing Wang,Yijun Du,Chenze Qi,Linjun Shao
A simple and green chemical modification coupled with electrospinning technique has been developed to incorporate tetrakis(triphenylphosphine)palladium [Pd(PPh 3 ) 4 ] inside crosslinked polystyrene nanofibers (Pd@CPS) as an efficient and stable heterogeneous palladium catalyst. The catalytic activities and recyclabilities of the prepared Pd@CPS catalyst have been evaluated by using Suzuki and Heck reactions of various aromatic halides separately with phenylboronic acid and alkenes. The Pd@CPS exhibited high-catalytic activities for the Suzuki and Heck reactions of aromatic iodides to afford the products in excellent yields (coupling yields >88%). The catalytic activities and the nanofiber structure remained essentially unchanged even after recycling for five times. The high activities and stabilities of the prepared Pd@CPS catalyst can be attributed to the ultrafine fiber and embedment of palladium active species inside the nanofibers.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Ziyuan Qiao,Jian Zhang,Chang Zhou,Feng-Shou Xiao
The development of efficient Beta zeolite for conversion of L-lactic acid (L-LA) to L,L-lactide (L-LT) is in urgent need but still remains challenging. Herein, we reported an enhancement of the L-LT yield by passivation of external acidic sites on aluminosilicate Beta zeolites by coating pure silica Beta (Al-Beta@Si-Beta). The passivation of external acidic sites was strongly evidenced by in situ 2,4,6-tritertbutylpyridine (TTBP) adsorption FT-IR spectra, where the external acidic sites of Al-Beta@Si-Beta were effectively covered. In the tests for conversion of L-LA to L-LT, the Al-Beta@Si-Beta exhibited much higher L-LT yield than commercial microporous Beta zeolite, which is reasonably attributed to that the passivation of external acidic sites of the Beta zeolite significantly decreases molecular weight of the reaction intermediates, favoring for reduction of coke formation. Furthermore, this strategy is extended to passivate mesoporous Beta zeolite (Al-Beta-meso@Si-Beta). As expected, the Al-Beta-meso@Si-Beta displayed higher L-LT yield than the Al-Beta@Si-Beta because the presence of mesoporosity in the zeolite catalyst is favorable for mass transfer in the conversion of L-LA to L-LT. The strategy for coating pure siliceous zeolite might offer a new opportunity to develop highly efficient zeolite catalysts for the production of L-LT in the future.
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JOURNAL OF POWER SOURCES
·
2023
·
IF 9.2
Yunji Xie,Kaiqi Wang,Di Liu,Jinhui Pang
Concentrated functionalization of the polymer side chain is widely considered as an effective structural strategy for improving the properties of anion exchange membranes (AEMs). However, the synthetic process typically involves highly toxic reagents. Herein, a series of poly(arylene ether ketone)s with densely benzyl- N -methylpiperidinium-functionalized hexaphenylbenzene pendants is synthesized, avoiding the demand of highly toxic reagents. The fabricated membranes present pronounced microphase separation resulting from the strong contrast in polarity between the hydrophobic polymer backbone and hydrophilic pendants. In contrast to analogous AEMs, the incorporation of bulky and rigid hexaphenylbenzene moieties enlarges the free volume within the membranes, which significantly enhances water absorption and inhibits dimensional change. Moreover, the presence of piperidinium-based cationic groups considerably enhances the alkaline stability of the membranes. One of the prepared membranes with an ion exchange capacity of 1.31 meq g −1 exhibits water uptake, swelling ratio, and hydroxide conductivity of 67.2%, 14.5%, and 49.2 mS cm −1 at 80 °C, respectively. The loss of conductivity is less than 6% after immersion in a 4 M KOH aqueous solution at 30 °C for 480 h. Additionally, a maximum power density of 340.1 mW cm −2 is achieved in the H 2 /O 2 single-cell test, indicating promising application potential for the fabricated membranes.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Xulong Pang,Yong Li,Xiaofu Wu,Bingmiao Zhang,Ming Hao,Yan Zhu,Yi Zhang,Chuanjiang Qin,Hongmei Zhan,Chuanli Qin
It is highly desirable to explore functionalized polymer semiconductor/g-C 3 N 4 heterojunction photocatalysts with the tight interfacial connection for promoting the photogenerated electron-hole pair separation, improving the hydrophilicity , extending the visible light response and achieving the efficient visible light-driven H 2 evolution. Herein, we synthesized novel poly[9,9-bis(3-ethyl phosphate propyl)fluorene- alt -benzothiadiazole] (PPFBT) with a phosphate ester on every repeating unit by the Suzuki polymerization and then fabricated PPFBT/hydroxylated g-C 3 N 4 (PPFBT/CN-OH) heterojunctions via a surface hydroxyl-induced assembly process. The ratio-optimized 5PPFBT/CN-OH shows the hydrogen evolution activity of 2662.4 μmol·g −1 ·h −1 , an 11.1-time enhancement compared to CN-OH. The improved photocatalytic activity is mainly attributed to the enhanced electron-hole pair separation due to the tight interfacial connection by hydrogen bond (P=O…H-O) and N…S interactions between PPFBT and CN-OH. It is verified that abundant phosphate ester groups of PPFBT improve the hydrophilicity and form coordination bonds with platinum (P=O:Pt) as a cocatalyst to facilitate water splitting for H 2 evolution. It is also confirmed that the enhanced electron-hole pair separation is mainly dependent on the excited high-energy level electron transfer from CN-OH to PPFBT. This work provides a rational molecular design strategy for constructing efficient functionalized polymer semiconductor/g-C 3 N 4 heterojunctions for sunlight-driven H 2 evolution.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Fan Wu,Hao Li,Yang Pan,Yingjia Wang,Yonghui Sun,Jianming Pan
The rapid and accurate recovery of precious metal palladium from waste resources has always been a hot and challenging topic. In addition, from the perspective of energy and environmental protection, the regeneration and rational use of waste are also crucial for a sustainable future. Here, an 8-aminoquinoline-modified core–shell magnetic nano stirring robot (MNSR@PGMA-AQ) towards Pd(Ⅱ) is reported which not only has ultra-high solid–liquid separation efficiency but also can accelerate the mass transfer rate in adsorption through self-stirring. A series of adsorption experiments show that MNSR@PGMA-AQ has fast adsorption kinetics, reaching 10.97 mg g −1 in 20 min, which is 85.87 % of the equilibrium adsorption capacity. And selectivity parameters such as distribution coefficient ( K D ), separation factor ( α ) and concentration factor ( CF ) demonstrate its excellent adsorption selectivity for Pd(Ⅱ). Moreover, it is proved that the adsorption mechanism of MNSR@PGMA-AQ towards Pd(Ⅱ) is ion exchange and chelation, which mainly depends on the functional monomer 8-aminoquinoline. The regeneration and palladium recovery experiments in actual samples further prove the application value of this novel robot. Furthermore, Pd-loaded MNSR@PGMA-AQ was used as a catalyst for the Suzuki-Miyaura cross-coupling reaction and investigated its catalytic performance to pursue the goal of waste regeneration and responsible catalyst manufacture.
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CARBOHYDRATE POLYMERS
·
2023
·
IF 11.2
Hao Ling,Lei Wang,Qixuan Lin,Quanbo Huang,Xiaoqian Zhang,Junli Ren,Ning Li,Cheng Zhou,Zhiwei Lin,Jingpeng Zhou,Wenguang Wei,Xiaohui Wang
Separating films with both high efficiency and large flux are desperately needed to meet the rising demand for the treatment of oily wastewater, while traditional oil/water separation papers with high separation efficiency usually suffered from low flux due to the unsuitable size of filtration pores. Herein, we report a bio-based porous, superhydrophobic , and antimicrobial hybrid cellulose paper with tunable porous structures for high flux oil/water separation. The size of pores in the hybrid paper can be tuned by both physical supports provided by the chitosan fibers and the chemical shielding supplied by the hydrophobic modification. The hybrid paper with increased porosity (20.73 μm; 35.15 %) and excellent antibacterial properties can efficiently separate a wide range of oil/water mixtures, solely by gravity, with outstanding flux (maximum of 23,692.69 L m −2 h −1 ), tiny oil interception, and high efficiency of over 99 %. This work provides new sights in the development of durable and low-cost functional papers for rapid and efficient oil/water separation.
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Advanced Materials Technologies
·
2018
·Vol. 4
·期 2
·1800515
·
IF 4.622
Juanjuan Wu,Ying Yan,Lijing Zhang,Zizhen Qin,Shengyang Tao
Mass transfer and catalyst recovery are both influential factors in heterogeneous catalytic processes, which significantly affect the reaction efficiency. Therefore, design and fabrication of reactors and catalysts with reasonable structure and property are central issues in heterogeneous reactions. Herein, agitating impeller (AI) with prismatic structure and catalytic property is conveniently constructed via the combination of 3D printing technology and polymeric ionic liquids (PILs). The further modification of the PILs on impellers endowed them with the ability of ion exchange, which helped to load Pd nanoparticles on the surface as catalysts for reduction, Suzuki coupling, and dye decolorization reactions. Prisms on the impellers significantly enhance the catalytic efficiency of these reactions through improving the mass transfer. The yield reaches nearly 100%. Catalytic impellers could be easily separated from the reactor and without a visible leak of Pd catalysts so that they could repeatedly be used more than ten times with high performance. The numerical simulation and experimental characterizations are both used to explore the mechanism of the mass transfer and the activity of the catalytic surface, which give a full understanding of the benefits of 3D printing and PILs in heterogeneous reactions.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Maiping Yang,Weiqu Liu,Chi Jiang,Chunhua Liu,Sha He,Yankun Xie,Zhengfang Wang
A facile and mild dip-coating method of fabricating superhydrophobic coating for cotton textiles was proposed. Cotton fabric was treated with TiO2 sol prepared under mild conditions and subsequently dip-coated by fluoropolymer (PHM). The PHM was synthesized by copolymerization of hexafluorobutyl methacrylate (HFBMA) and 3-methacryloxypropyltrimethoxysilane (MPS) to replace long-chain fluoroalkylsilanes, which are costly and potentially harmful. The coated textile displayed wonderful superhydrophobicity with a water contact angle of 153.5°. Additionally, the stability of the coated textile was tested by placement in acidic and alkali solutions, ultrasonic processing, and washing, during which it exhibited desirable durability. Furthermore, the surface showed an excellent biomimetic self-cleaning effect of removing both liquid pollutant and solid powder stains. Importantly, the prepared textile exhibited efficient oil–water separation for its superhydrophobicity and superoleophilicity. These advantages make it an ideal material for large-scale industrial applications under various conditions.
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