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Integrated electrocatalysts derived from metal organic frameworks for gas-involved reactions

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Nano Materials Science 2023年第2期5卷 161-176页

作者： Yuke Song Wenfu Xie Mingfei Shao xue duan State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing100029China

Integrated electrocatalysts(IECs)containing well-defined functional materials directly grown on the current collector have sparked increasing interest in the fields of electrocatalysis owing to efficient activity,high stability and the fact that they are easily assembled into ***,metal organic frameworks(MOFs)provide a promising platform for constructing advanced IECs because of their properties of low cost,large surface area and efficient structural *** this review,the design principles of state-of-the-art IECs based on MOFs are presented,including by hydrothermal/solvothermal,template-directed,electrospinning,electrodeposition and other *** high performance of MOF-derived IECs has also been demonstrated in electrocatalytic gasinvolved *** is promising for green energy storage and *** structure-activity relationship and performance improvement mechanism of IECs are uncovered by discussing some in situ technologies for ***,we provide an outlook on the challenges and prospects in this booming field.

关键词： Integrated electrocatalyst Metal organic framework Structure-activity relationship Gas-involved reaction

Smoke suppressant in flame retarded thermoplastic polyurethane composites: Synergistic effect and mechanism study

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Nano Research 2021年第11期14卷 3926-3934页

作者： Hongyuan Ren Kelan Qing Ying Chen Yanjun Lin xue duan State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing100029China

Considerable smoke and toxic volatiles generation has compromised the application of thermoplastic polyurethane (TPU) and caused a great threat to human life. Here, nano-MgFe layered double hydroxide (MgFe-LDH) with uniform particle size was synthesized to reduce smoke density and toxic gases of TPU composites using ammonium polyphosphate (APP) as a flame retardant agent. The results show that the combination of 16 wt.% APP and 4 wt.% MgFe-LDH greatly decreased the smoke density (D20min and Ds, max), smoke production rate (SPR) and heat release rate (HRR) of TPU composites. Furthermore, the MgFe-LDH synergist demonstrated high efficiency in decreasing total volatiled products and toxic volatiles evolved, such as the CO, HCN and isocyanates. The reason was mainly attributed to the chemical reaction between MgFe-LDH and APP, which can promote the compactness of char layers with fine microstructure formed in the decomposition process of MgFe-LDH/APP/TPU composites. The protective char layers could act as barriers between combustion zone and matrix to protect the unburned substrate and promote smoke suppression effect.

关键词： layered double hydroxide thermoplastic polyurethane smoke suppression synergistic effect

Layered double hydroxides:Scale production and application in soil remediation as super-stable mineralizer

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Chinese Journal of Chemical Engineering 2022年第1期35卷 42-48页

作者： Fangqi Mao Peipei Hao Yuquan Zhu Xianggui Kong xue duan State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China

Soil contamination by heavy metals has presented severe risks to human health through food *** one of the most promising remediation technologies,in-situ immobilization strategy has been widely adopted in ***,considering the large quantities of contaminated soil,it is still a huge challenge to design low-cost amendments with strong and long-term immobilization *** double hydroxides(LDHs)have drawn tremendous attention in fundamental research and practical application because of their unique ***,owing to its super-stable mineralization effect to heavy metal ions,LDHs have exhibited great potential in the field of soil *** this work,we mainly focused on the scale production strategy of LDHs with low-cost,and its application in soil ***,several key challenges in using LDHs as amendments for immobilization of heavy metal ions are *** hope that this mini-review could shed light on the sustainable development of LDHs as amendment for heavy metals in future research directions.

关键词： Heavy metals Pollution Remediation Layered double hydroxides Scale-up Super-stable mineralization effect

Connected Vehicles Computation Task Offloading Based on Opportunism in Cooperative Edge Computing

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Computers, Materials & Continua 2023年第4期75卷 609-631页

作者： duan xue Yan Guo Ning Li Xiaoxiang Song College of Communications Engineering Army Engineering University of PLANanjing210007China College of Computer Science Liupanshui Normal UniversityLiupanshui553000China

The traditional multi-access edge computing (MEC) capacity isoverwhelmed by the increasing demand for vehicles, leading to acute degradationin task offloading performance. There is a tremendous number ofresource-rich and idle mobile connected vehicles (CVs) in the traffic network,and vehicles are created as opportunistic ad-hoc edge clouds to alleviatethe resource limitation of MEC by providing opportunistic computing *** this basis, a novel scalable system framework is proposed in thispaper for computation task offloading in opportunistic CV-assisted *** this framework, opportunistic ad-hoc edge cloud and fixed edge cloudcooperate to form a novel hybrid cloud. Meanwhile, offloading decision andresource allocation of the user CVs must be ascertained. Furthermore, thejoint offloading decision and resource allocation problem is described asa Mixed Integer Nonlinear Programming (MINLP) problem, which optimizesthe task response latency of user CVs under various constraints. Theoriginal problem is decomposed into two subproblems. First, the Lagrangedual method is used to acquire the best resource allocation with the fixedoffloading decision. Then, the satisfaction-driven method based on trial anderror (TE) learning is adopted to optimize the offloading decision. Finally, acomprehensive series of experiments are conducted to demonstrate that oursuggested scheme is more effective than other comparison schemes.

关键词： Multi-access edge computing opportunistic ad-hoc edge cloud offloading decision resource allocation TE learning

Studies on the Surface Properties of MCM-41

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Chemical Research in Chinese Universities 2002年第3期18卷 242-245页

作者： HE Jing duan xue EVANS DG LI Cheng yue The Key Laboratory of Science and Technology of Controllable Chemical Reactions Ministry of EducationBeijing University of Chemical TechnologyBeijing 100029P.R.China

MCM 41 materials with a well ordered long range structure, a large pore size and a high surface area have been synthesized. Their surface properties including the number and the nature of the surface hydroxyl groups and surface hydrophobicity/hydrophilicity have been investigated by means of 29 Si MAS NMR and FT IR spectra and TPD of probe molecules. The results clearly show that the surface of MCM 41 has an abundance of acidic silanol groups, and that the hydrophobicity/hydrophilicity can be modified by the introduction of Al and transition metals Ti, Cr, Ni and Fe into it.

关键词： Hydroxyl group Hydrophobicity/Hydrophilicity MCM 41

Layer-by-layer assembly of long-afterglow self-supporting thin films with dual-stimuli-responsive phosphorescence and antiforgery applications

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Nano Research 2017年第10期10卷 3606-3617页

作者： Rui Gao Dongpeng Yan David G. Evans xue duan State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China Beijing Key Laboratory of Energy Conversion and Storage Materials College of Chemistry Beijing Normal University Beijing 100875 China

The assembly of thin films （TFs） having long-lasting luminescence can be expected to play an important role in the development of new-generation smart sensors, anti-counterfeiting materials, and information-encryption systems. However, such films are limited compared with their powder and solution counterparts. In this study, by exploiting the self-organization of phosphors in the two-dimensional （2D） galleries between clay nanosheets, we developed a method for the ordered assembly of long-afterglow TFs by utilizing a hydrogen-bonding layer-by-layer （LBL） process. Compared with the pristine powder, the TFs exhibit high polarization and up-conversion room-temperature phosphorescence （RTP）, as well as enhanced quantum yields and luminescence lifetimes, allowing them to be used as room-temperature phosphorescent sensors for humidity and oxygen. Moreover, modified clay-based hybrids with multicolor RTP can serve as anti-counterfeiting marks and triple-mode 2D barcode displays. We anticipate that the LBL assembly process can be extended to the fabrication of other inorganic--organic room-temperature phosphorescent hybrids with smart luminescent sensor and antiforgery applications.

关键词： layer-by-layer self-supporting thin film two-dimensional (2D) ultrathin nanosheets sensor phosphorescence

Photoresponsive thin films containing an azobenzene derivative intercalated with a layered double hydroxide

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Chinese Science Bulletin 2010年第34期55卷 3894-3900页

作者： WANG XinRui LU Jun WEI Min duan xue State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China

Two kinds of optically transparent thin films with photochromic properties have been fabricated based on co-intercalation of 4-(4-anilinophenylazo)benzenesulfonate(AO5)and sodium dodecylbenzene sulfonate(SDS)into the galleries of a ZnAl layered double hydroxide(LDH)by two synthetic methods:solvent evaporation and in situ *** two films possess LDH crystallites in different orientations relative to the substrates depending on their fabrication method:horizontal and *** relationship between the photochromic behavior of the interlayer chromophore and the orientation of the LDH crystallites is studied *** orientation of the LDH crystallite influences the photochromic behavior of the *** films exhibited different absorption and wettability characteristics,providing the potential for application of dye-LDH films as photochromic materials and light sensitive switches.

关键词：层状双金属氢氧化物偶氮苯衍生物光敏薄膜光致变色行为十二烷基苯磺酸钠晶粒取向光致变色材料 LDH

Exchange-Biased NiFe_(2)O_(4)/NiO Nanocomposites Derived from NiFe-Layered Double Hydroxides as a Single Precursor

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Nano Research 2010年第3期3卷 200-210页

作者： Xiaofei Zhao Sailong Xu Lianying Wang xue duan Fazhi Zhang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China

NiFe_(2)O_(4) nanoparticles(<10 nm)embedded in a NiO matrix have been fabricated by calcining the corresponding Ni^(Ⅱ)Fe^(Ⅲ)-layered double hydroxide(LDH)precursors at high temperature(500℃).Compared with the NiFe_(2)O_(4)/NiO nanocomposite obtained by calcination of a precursor prepared by a traditional chemical coprecipitation method,those derived from NiFe-LDH precursors show much higher blocking temperatures(TB)(~380 K).The enhanced magnetic stability can be ascribed to the much stronger interfacial interaction between NiFe_(2)O_(4) and NiO phases due to the topotactic nature of the transformation of the LDH precursor to the NiFe_(2)O_(4)/NiO composite *** tuning the Ni^(Ⅱ)/Fe^(Ⅲ) molar ratio of the NiFe-LDH precursor,the NiFe_(2)O_(4) concentration can be precisely controlled,and the TB value as well as the magnetic properties of the final material can also be *** work represents a successful example of the fabrication of ferro(ferri)magnetic(FM)/antiferrimagnetic(AFM)systems with high magnetic stability from LDH *** method is general and may be readily extended to other FM/AFM systems due to the wide range of available LDH precursors.

关键词： Layered double hydroxide topotactic mechanism interfacial interaction exchange bias magnetic stability

A Co-N/C hollow-sphere electrocatalyst derived from a metanilic CoAl layered double hydroxide for the oxygen reduction reaction, and its active sites in various pH media

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Nano Research 2017年第7期10卷 2508-2518页

作者： Jun Wang Liqun Li Xu Chen Yanluo Lu Wensheng Yang xue duan State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China

Transition-metal-coordinating nitrogen-doped carbon catalysts （M-N/C, M = Co, Fe, Mn, Ni, etc.） are considered one of the most promising nonprecious-metal electrocatalysts for the oxygen reduction reaction （ORR）. However, they suffer from low ORR catalytic activity, and their active sites have not been fully identified. Herein, we report the synthesis of a porous Co-N/C hollow-sphere electrocatalyst by carbonization of metanilic anions between the layers of a Co-A1 layered double hydroxide. The as-prepared Co-N/C catalyst exhibited excellent ORR catalytic activity with a high half-wave potential and a large diffusion-limited current in alkaline and neutral solutions. The performance of the catalyst was comparable to those of commercial Pt/C electrocatalysts. Through investigating the effects of mask ions （SCN- and F-） on the ORR activity of the Co-N/C catalyst, and comparing the ORR activity before and after the destruction of Co-Nx sites in different pH media, we concluded that the Co-Nx sites act directly as the ORR active sites in acidic and neutral solutions, but have a negligible effect on the ORR activity in alkaline conditions.

关键词： confined space hollow carbon sphere hierarchical pore structure electrocatalysts oxygen reduction reaction