LUMINESCENCE
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2020
·Vol. 36
·期 2
·431-442
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IF 1.855
Qian Liu,Feifei Zhao,Bingfeng Shi,Changli Lü
Carbon dots (CDs) with excellent optical properties are widely used in biomedicine, fluorescence sensing, and light-emitting diodes (LEDs). However, it is still a challenge to prepare CDs that can stably emit red fluorescence in the water environment. In this study, polydopamine-encapsulated luminescent carbon dots (CDs@PDA) with an encapsulating structure were synthesized at room temperature from p -phenylenediamine-derived red-light CDs as the core and using mussel-inspired chemical properties of polydopamine (PDA). In the binary system of water:ethanol = 1: 3 (volume ratio), the as-prepared CDs@PDA had a dual emission of ultraviolet light (330 nm) and red light (640 nm) with the fluorescence quantum yields of 8.0 and 15.5%, respectively, at the same time under 285 nm light excitation. The as-prepared CDs@PDA could be directly used for fluorescence selective sensing of 4-nitrophenol (4-NP) and Fe 3+ through simultaneously quenching of ultraviolet and red fluorescence based on the internal filtration effect mechanism with detection limits of 3.44 and 3.75 μM, respectively. This research showed that PDA-coated CDs can significantly improve the photoluminescence stability of CDs with new optical features. This means that the encapsulated structure of mussel chemistry is very helpful for expanding the application range of CDs in the water environment.
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RSC Advances
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2020
·Vol. 10
·期 61
·37014-37022
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IF 3.119
Shengfu Liao,Jianguo Liu,Long Yan,Qiying Liu,Guanghui Chen,Longlong Ma
Anthraquinones are recognized as high efficiency photocatalysts which can perform various redox reactions in aqueous or organic phases. We have experimentally proven that 2-BrAQ can undergo hydrogen transfer with an alpha-aromatic alcohol under light conditions, thereby efficiently oxidizing the aromatic alcohol to the corresponding product. The yield of 1-phenethanol to acetophenone can reach more than 96%. In subsequent catalyst screening experiments, it was found that the electronegativity of the substituent at the 2 position of the anthraquinone ring and the acidity of the solvent affect the photocatalytic activity of anthraquinones. After using various aromatic alcohol substrates, 2-BrAQ showed good conversion and selectivity for most aromatic alcohols, but showed C–C bond cleavage and low selectivity with non-α-position aromatic alcohols. In order to explore the mechanism of the redox reaction of 2-BrAQ in acetonitrile solution, the corresponding free radical reaction pathway was proposed and verified by density functional theory (DFT). Focusing on calculations for 2-BrAQ during the reaction and the first-step hydrogen transfer reaction between the 2-BrAQ triplet molecule and the 1-phenylethanol molecule, we recognized the changes that occurred during the reaction and thus have a deeper understanding of the redox reaction of anthraquinone compounds in organic systems.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Ming Liu,Xun Zhu,Qiang Liao,Rong Chen,Dingding Ye,Gang Chen,Kun Wang,Sihong Song
Benefiting from the structures of membrane and microchannel, catalytic membrane microreactors are attractive for multiphase catalytic reactions. In addition to the membrane development, the fabrication of an efficient catalyst layer on a supporting layer is also significant for improving the performance of the membrane microreactor. In the present study, a plate-type catalytic membrane microreactor with the catalyst layer prepared by the layer-by-layer self-assembly technology along with the in situ adsorption and reduction was proposed. Herein, polydopamine (PDA) and polyelectrolyte multilayers (PEMs) were coated on the surface of the polydimethylsiloxane supporting membrane to adsorb more PdCl42– ions for the subsequent reduction. The synthesized catalyst layer termed as PDA/PEMs/Pd was characterized by analyzing the chemical composition and surface morphology. In addition, the catalytic performance of the developed microreactor was tested by using hydrogenation of nitrobenzene. The results showed that the use of both PDA and PEMs for preparing the catlayst layer yielded better conversion and durability than the use of PDA or PEMs alone. Besides, the nitrobenzene solution flow rate had an adverse impact of the nitrobenzene conversion resulting from the decreased residence time. With the increase of the hydrogen flow rate, the nitrobenzene conversion could be improved due to the increased gas permeation. The nirobenzene conversion also increased with a reduction in the initial concentration of nitrobenzene. In short, employing the layer-by-layer self-assembly technology for the catalyst layer preparation is promising for catalytic membrane microreactors toward multiphase catalytic reactions.
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SENSORS AND ACTUATORS B-CHEMICAL
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2020
·
IF 7.1
Tian Tao,Yang Zhou,Mingyu Ma,Hanping He,Nan Gao,Zhiwei Cai,Gang Chang,Yunbin He
A novel graphene electrochemical transistor (GECT) based on zirconia/reduced graphene oxide (ZrO 2 /rGO) nanocomposites functionalized gate electrode and graphene as channel was successfully designed and fabricated for highly sensitive detection of methyl parathion (MP). ZrO 2 /rGO nanocomposites were co-electrodeposited on a glassy carbon electrode considering the special affinity of ZrO 2 toward phosphate groups and high specific surface area of rGO. The sensing mechanism is attributed to the change of effective gate voltage applied to GECT induced by the electrochemical reactions of MP at the functionalized gate electrode, thus tuning the channel carrier concentration and the channel current. Due to the excellent electrocatalytic activity of ZrO 2 /rGO on the gate and the high carrier mobility of graphene in the channel, the developed sensor exhibited excellent sensing performances with ultra-low detection limit (10 pg/mL) and ultra-wide linear range from 10 pg/mL to 10 μg/mL, which especially stand out of the reported devices. The GECT sensor also showed good selectivity toward usual interferents and strong practicality through testing MP in Chinese cabbage samples. The developed GECT devices provided not only the novel platform for pesticide detection with high sensitivity but the new method of enhancing the sensing performance through specifically functionalized gate electrode.
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Journal of Materials Chemistry A
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2020
·Vol. 8
·期 32
·16392-16404
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IF 11.301
Qiao-Ling Mo,Xin Lin,Zhi-Quan Wei,Xiao-Cheng Dai,Shuo Hou,Tao Li,Fang-Xing Xiao
Precise tuning of photoinduced charge separation and transport has been an enduringly central issue in photocatalysis but has met with limited success. In particular, the controllable, accurate and simultaneous modulation on the charge (electrons/holes) transfer pathway in photocatalytic selective organic transformations has not yet been achieved. Herein, as a proof-of-principle demonstration, we report the fine tuning of charge separation/migration by smartly constructing spatially separated charge transport channels over diverse metal/transition metal chalcogenide [(M/TMC), M = Au, Ag, Pd, TMCs = ZnIn2S4, CdIn2S4, In2S3, and CdS] heterostructure photosystems, which were elaborately crafted by an efficient surface ligand-triggered electrostatic self-assembly. Accordingly, tailor-made positively charged branched poly(ethylene imine) (bPEI)-capped metal nanocrystals (NCs) were controllably and uniformly anchored on the two-dimensional (2D) TMC nanosheet (NS) framework, resulting in well-defined metal/TMC heterostructures. We found that electrons photoexcited over TMC NSs could be spontaneously, smoothly and unidirectionally migrated to closely integrated metal@bPEI NCs, wherein the metal core acts as a Schottky-type electron-trapping reservoir and bPEI ligand as a hole transfer mediator, synergistically affording spatially separated charge transfer channels and expediting the charge separation/transfer efficiency. Benefiting from these merits, the self-assembled M/TMC heterostructures exhibited conspicuously boosted photoactivities in the visible light-driven selective organic transformation toward the anaerobic reduction of aromatic nitro compounds to amino derivatives, which are superior to pristine TMCs and M/TMCs without ligand encapsulation. More significantly, the self-assembly strategy and charge modulation concept are universal for diverse metal NCs and TMCs. Thus, our study provides a general and effective protocol to construct a host of metal/TMC heterostructures and stimulates new inspiration for modulating tunable charge separation/migration for substantial solar energy conversion.
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Nature Catalysis
·
2021
·Vol. 4
·期 2
·134-143
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IF 41.813
Zhao Yafei,Zhou Huang,Zhu Xiaorong,Qu Yunteng,Xiong Can,Xue Zhenggang,Zhang Qingwei,Liu Xiaokang,Zhou Fangyao,Mou Xiaoming,Wang Wenyu,Chen Min,Xiong Ya,Lin Xingen,Lin Yue,Chen Wenxing,Wang Hui-Juan,Jiang Zheng,Zheng Lirong,Yao Tao,Dong Juncai,Wei Shiqiang,Huang Weixin,Gu Lin,Luo Jun,Li Yafei,Wu Yuen
Single-atom catalysts often exhibit unexpected catalytic activity for many important chemical and biological reactions with respect to their bulk counterparts, and have been recognized as potential substitutes for natural enzymes. Here we report a biomimetic composite, yolk–shell Pd 1 @Fe 1 , that features two compatible single-atom systems with atomically dispersed Fe 1 sites in a N-doped carbon shell and Pd 1 sites in a yolk derived from a metal–organic framework. Directly utilizing the O 2 and H 2 sources generated on-site from the electrocatalytic overall water splitting, the as-synthesized yolk–shell Pd 1 @Fe 1 could simultaneously catalyse nitroaromatic hydrogenation and alkene epoxidation reactions and lead to a cascade synthesis of amino alcohols. Our findings provide a versatile strategy to integrate different single metal sites within one system to allow the continuous and easy synthesis of complex compounds for various challenging reactions.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Ming Liu,Xun Zhu,Qiang Liao,Rong Chen,Dingding Ye,Gang Chen
In the present study, a novel stacked catalytic membrane microreactor assembled by microfluidic sheets and gas-permeable membranes was developed for gas–liquid–solid multiphase catalytic reactions. The developed microreactor consisted of multilayered perforated microchannels for supplying liquid reactants and perforated microchambers for supplying gas reactants, which were separated by poly(dimethylsiloxane) membranes with coated catalysts. Gas and liquid reactants flowed through their independent passageways layer by layer. Gas reactants bidirectionally permeated through the gas-permeable membrane to the catalyst layer, improving the gas utilization. Catalyst layers were prepared and immobilized on the membranes through layer-by-layer self-assembly and in situ reduction technology. Unlike other stacked microreactors, the integration of microchannels, microchambers, and membranes into one unit circumvented flow maldistribution, low durability, and low throughput of the microreactor. Furthermore, the scale-up of the membrane microreactor could be easily realized by increasing the number of microfluidic sheets and membranes. The catalytic performance was evaluated by nitrobenzene hydrogenation over palladium nanocatalyst. Results showed that the stacked catalytic membrane microreactor enabled a stable and efficient operation for 50 h. As the number of stacked layers was increased, the durability was continuously increased. The conversion was increased with increasing hydrogen flow rate or decreasing nitrobenzene flow rate. In addition, the increased inlet nitrobenzene concentration led to more serious catalyst deactivation, which decreased the conversion. In general, the stacked catalytic membrane microreactor developed in this study creates a new approach to design membrane microreactors for multiphase catalytic reactions.
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Energy Storage Materials
·
2020
·
IF 16.28
Weicai Zhang,Zhuohao Xie,Mingtao Zheng,Hang Hu,Yong Xiao,Yingliang Liu,Yeru Liang
Evolution of fast-charging alkali-metal ion battery (AIB) is of great importance, but severely limited by the high ion/electron transport resistance in the electrode structure . Carbon-based composites have demonstrated competitive results for accelerating the related technology development. However, their efficient design, versatile synthesis and diverse structural variability remain the major challenges. Herein, we propose a general and versatile protocol for synthesizing a hierarchical network structure composed of metal compound ( e.g. , metal oxide , metal selenide and metal sulfide) encapsulated in carbon nanoparticle unit, and demonstrate its superiority for fast-charging anode of AIB. Key to this strategy is utilization of a rational hybrid assembly comprising of chelating resin and metal ions as building blocks. The strong coordinate-covalent bond between chelating resin and metal ions not only realizes a highly homogeneous organic/inorganic interface at the molecular level, but also confines metal ions to in-situ generate metal compound nanoparticles uniformly distributed into the carbon framework after a carbonization treatment, endowing a strong binding at the carbon/non-carbon interface structure . Benefitting from the well-organized structure, the resultant network-structured metal compound@carbon composites exhibit extraordinary fast-charging alkali-metal ion storage performance. For example, the typical network-structured Fe 2 O 3 @carbon composite anode can be fully charged within 2.2 min and discharge continuously for more than 120 min with a large charge/discharge capacity of 730 mAh g −1 in lithium ion batteries , and is able to be fully charged within 5.6 min accompanying with a long discharge time of about 110 min and a high charge/discharge capacity of 92 mAh g −1 in potassium ion batteries .
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Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 17
·8360-8375
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IF 11.301
Shuai Xu,Ming-Hui Huang,Tao Li,Zhi-Quan Wei,Xin Lin,Xiao-Cheng Dai,Shuo Hou,Xiao-Yan Fu,Fang-Xing Xiao
Modulating photo-induced charge separation/transfer constitutes a central challenge in heterogeneous photocatalysis. Despite advancements in this area, finely tuning directional electron migration without involving conventional co-catalysts [e.g., metal nanocrystals and transition metal dichalcogenides (TMDs)] for boosted photoredox catalysis has not yet been explored. Herein, we report the exquisite design of a novel and general macromolecule-modulated photoredox selective organic transformation system, wherein an ultrathin macromolecular poly(diallyldimethylammonium chloride) (PDDA) layer was integrated at the interface of wide-band-gap (WBG) and narrow-band-gap (NBG) semiconductors to construct heterostructured photocatalysts. The ultra-thin PDDA interim layer expedites interfacial unidirectional electron transfer from the NBG to WBG semiconductor, resulting in a cascade electron transfer channel. The favorable energy level alignment among the building blocks, intimate interfacial integration and multilayered nanoarchitecture endow the WBG@PDDA@NBG heterostructures with substantially enhanced and versatile photoredox performance toward the selective oxidation of aromatic alcohols to aldehydes and the anaerobic reduction of nitroaromatics to amino compounds under visible light irradiation. This can be ascribed to the crucial role of the ultrathin intermediate PDDA layer as a highly efficient metal and TMD-free charge transfer mediator, relaying the electrons from the NBG to WBG semiconductor and slowing charge recombination. Our work could open up new frontiers to exploit diverse metal and TMD-free photocatalytic systems and provide a first insight into the fine tuning of charge transport utilizing non-conductive ionic polymers for solar energy conversion.
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Materials
·
2020
·Vol. 13
·期 7
·1513
·
IF 3.057
Jialing Kang,Mengjia Wang,Chenbao Lu,Changchun Ke,Pan Liu,Jinhui Zhu,Feng Qiu,Xiaodong Zhuang
Due to the growing demand for energy and imminent environmental issues, hydrogen energy has attracted widespread attention as an alternative to traditional fossil energy. Platinum (Pt) catalytic hydrogen evolution reaction (HER) is a promising technology to produce hydrogen because the consumed electricity can be generated from renewable energy. To overcome the high cost of Pt, one effective strategy is decreasing the Pt nanoparticle (NP) size from submicron to nano-scale or even down to single atom level for efficient interacting water molecules. Herein, atomically dispersed Pt and ultra-fine Pt NPs embedded porous carbons were prepared through the pyrolysis of Pt porphyrin-based conjugated microporous polymer. As-prepared electrocatalyst exhibit high HER activity with overpotential of down to 31 mV at 10 mA cm−2, and mass activity of up to 1.3 A mgPt−1at overpotential of 100 mV, which is double of commercial Pt/C (0.66 A mgPt−1). Such promising performance can be ascribed to the synergistic effect of the atomically dispersed Pt and ultra-fine Pt NPs. This work provides a new strategy to prepare porous carbons with both atomically dispersed metal active sites and corresponding metal NPs for various electrocatalysis, such as oxygen reduction reaction, carbon dioxide reduction, etc.Keywords:platinum;atomically dispersed active site;nanoparticle;porous carbon;hydrogen evolution reaction
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Wenchang Sun,Xu Zhang,Yueming Hou,Yanji Wang,Xiaomei Wang,Wei Xue
As a promising synthesis route, indirect hydration of cyclohexene into cyclohexanol by heterogeneous catalysts shows high conversion than that in direct hydration; however, increasing the yield of cyclohexanol from cyclohexene is still a significant challenge. Notably, fabricating a high-performance catalyst is an effective method to improve the yield of the target product. Consequently, a kind of polystyrene-based hierarchically macro–mesoporous solid acid (HP CLPS-SO3H) was successfully prepared by the combination of a colloidal crystal template method with Friedel–Crafts (F–C) cross-linking. Compared with that of other catalysts (3DOM CLPS-SO3H, Amberlyst-15, and HZSM-5) with single-sized pore distributions, HP CLPS-SO3H shows remarkable catalytic performance under mild conditions, in which 90.2% cyclohexanol yield from cyclohexene was obtained. Even after 10 times reuse of the HP solid acid, 80.3% cyclohexanol yield was retained. Moreover, the original morphology was well preserved and the acid sites almost hardly reduced. The as-prepared HP CLPS-SO3H shows promising prospects in the field of cyclohexanol production.
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ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Ming Liu,Xun Zhu,Qiang Liao,Rong Chen,Dingding Ye,Gang Chen,Kun Wang
A catalytic membrane microreactor is a potential tool for the application in multiphase catalytic reactions. Currently, the installation of a permeable ultrathin membrane to separate the reactants with different phases and the grafting of a catalyst layer on the membrane in a microreactor remain challenging. In this work, a catalytic ultrathin membrane microreactor with an ultrathin freestanding supporting membrane was developed for nitrobenzene hydrogenation, which was formed by the interfacial polycondensation reaction with parallel laminar flow in a microchannel, followed by catalyst layer immobilization on one side of the ultrathin membrane surface using the layer-by-layer self-assembly technique and in situ reduction. The ultrathin freestanding membrane ensured a stable gas/liquid contact interface and good hydrogen permeability. The developed membrane microreactor could exhibit high catalytic performance under mild conditions, demonstrating its superior mass transport. In addition, the effects of the thickness of the ultrathin freestanding membrane, flow rates, and inlet nitrobenzene concentration were investigated to obtain the optimum operating conditions. The experimental results demonstrate that this newly developed membrane microreactor is a promising candidate for multiphase catalytic reactions.
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