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Electrostatically connected nanoarchitected electrocatalytic films for boosted water splitting

Nano Research 2024年第3期17卷 1114-1122页

作者： Chao-Peng Wang Hao Sun Gang Bian Jia-Xi Wang Xixi Pang Guoqi Wang Jian Zhu xian-he bu School of Materials Science and Engineering National Institute for Advanced MaterialsNankai UniversityTianjin 300350China Tianjin Key Laboratory of Metal and Molecule-Based Material Chemistry Nankai UniversityTianjin 300350China Tianjin Key Laboratory for Rare Earth Materials and Applications Nankai UniversityTianjin 300350China

Active sites of two-dimensional(2D)electrocatalysts are often partially blocked owing to their inevitable stacking and hydrophobic polymeric binders in macroscale electrodes,therefore impeding their applications in efficient ***,using layered double hydroxide(LDH)nanosheets as a model 2D electrocatalyst,we demonstrate that their performance toward water splitting can be boosted when they are electrostatically assembled into an organized structure pillared by hydrophilic polyelectrolytes or nanoparticles in a layer-by-layer(LbL)*** particular,their mass activity on a planar electrode can be as large as 2.267 mA·μg^(-1) toward oxygen evolution reaction(OER),when NiFe-LDH nanosheets are electrostatically connected by poly(sodium 4-styrenesulfonate)(PSS),while drop-casted NiFe-LDH nanosheets only have a mass activity of 0.116 mA·μg^(-1).In addition,these homogeneous NiFe-LDH nanofilms can be easily deposited on three-dimensional(3D)surfaces with high areas,such as carbon cloths,to serve as practical electrodes with overpotentials of 328 mV at a current density of 100 mA·cm^(-2),and stability for 40 ***,Pt nanoparticles can be LbL assembled with NiFe-LDH as bifunctional electrodes for synergistically boosted oxygen and hydrogen evolution reactions(heR),leading to successful overall water splitting powered by a 1.5 V *** study heralds the spatial control of 2D nanomaterials in nanoscale precision as an efficient strategy for the design of advanced electrocatalysts.

关键词： layer-by-layer(LbL)assembly layered double hydroxides(LDH) two-dimensional(2D)electrocatalysts oxygen evolution reaction(OER) water splitting

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Concomitant Photoresponsive Chiroptics and Magnetism in Metal-Organic Frameworks at Room Temperature

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Research 2021年第1期2021卷 265-276页

作者： Bin Xia Qian Gao Zhen-Peng Hu Qing-Lun Wang Xue-Wei Cao Wei Li You Song xian-he bu College of Chemistry State Key Lab of Elemento-Organic ChemistryNankai UniversityTianjin 300071China School of Physics Nankai UniversityTianjin 300071China School of Materials Science and Engineering Tianjin Key Lab of Metal and Molecule-Based Material ChemistryNankai UniversityTianjin 300350China State Key Lab of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjing 210023China

Stimulus-responsive metal-organic frameworks(MOFs)can be used for designing smart ***,we report a family of rationally designed MOFs which exhibit photoresponsive chiroptical and magnetic properties at room *** this design,two specific nonphotochromic ligands are selected to construct enantiomeric MOFs,{Cu_(2)(L-mal)_(2)(bpy)_(2)(H_(2)O)·3H_(2)O}n(1)and{Cu_(2)(D-mal)_(2)(bpy)_(2)(H_(2)O)·3H_(2)O}_(n)(2)(mal=malate,bpy=4,4’−bipyridine),which can alter their color,magnetism,and chiroptics concurrently in response to *** UV or visible light irradiation,long-lived bpy−radicals are generated via photoinduced electron transfer(PET)from oxygen atoms of carboxylates and hydroxyl of malates to bpy ligands,giving rise to a 23.7%increase of magnetic susceptibility at room *** participation of the chromophores(-OH and-COO^(−))bound with the chiral carbon during the electron transfer process results in a small dipolar transition;thus,the Cotton effects of the enantiomers are weakened along with a photoinduced color *** work demonstrates that the simultaneous responses of chirality,optics,and magnetism can be achieved in a single compound at room temperature and may open up a new pathway for designing chiral stimuli-responsive materials.

关键词： temperature. materials. optics

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Rational design of ZnCdS/TpPa-1-COF heterostructure photocatalyst by strengthening the interface connection in solar hydrogen production reactions

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Nano Research 2024年第3期17卷 1027-1034页

作者： Di Yang Zhi-Gang Li Xinghao Zhang Zenghuan Ren Weihan Lu Haining Liu Xiaomeng Guo Jijie Zhang xian-he bu Tianjin Key Laboratory of Metal and Molecule-Based Material Chemistry School of Materials Science and EngineeringNankai UniversityTianjin 300350China College of Chemistry and Pharmaceutical Engineering Hebei University of Science and TechnologyShijiazhuang 050018China State Key Laboratory of Elemento-Organic Chemistry College of ChemistryNankai UniversityTianjin 300071China

ZnCdS quantum dots(QDs)are highly coveted in photocatalysis research for their exceptional visible-light responses and high light-absorption ***,their practical application is hindered by their tendency to aggregate,due to having high surface *** address this issue,herein,a heterostructure is synthesized by growing ZnCdS QDs with a size of approximately 5 nm onto the surface of a two-dimensional(2D)covalent organic framework(COF),*** approach suppresses the aggregation of the QDs and improves their *** ZnCdS/TpPa-1-COF composite exhibited a peak hydrogen evolution rate of 6244.16μmol·g^(-1)·h^(-1),which was 2.89 and 4.18 times greater than that of ZnCdS and TpPa-1-COF,*** zero-dimensional/two-dimensional(0D/2D)heterojunction formed by ZnCdS and TpPa-1-COF generates a strong interfacial force,which is attributed to the intimate contact between the *** connections accelerate charge separation,improve the utilisation of reduced electrons,and reduce the extent of agglomeration of the ZnCdS QDs,thereby resulting in high hydrogen production activity of the ***,the photocatalytic mechanism is studied using Kelvin probe force microscopy and theoretical *** study offers a novel approach for creating sulfide photocatalysts and is crucial for investigating the potential practical applications of the related photocatalysts.

关键词： covalent organic frameworks quantum dots photocatalysis hydrogen generation heterojunction

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Crystalline-State Solvent:Metal-Organic Frameworks as a Platform for Intercepting Aggregation-Caused Quenching

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Chinese Journal of Chemistry 2022年第5期40卷 589-596页

作者： Yan-Yuan Jia Jia-Cheng Yin Na Li Ying-Hui Zhang Rui Feng Zhao-Quan Yao xian-he bu School of Materials Science and Engineering Tianjin Key Laboratory of Metal and Molecule-Based Material ChemistryNankai UniversityTianjin300350 China State Key Laboratory of Elemento-Organic Chemistry College of ChemistryNankai UniversityTianjin300071 China

The sequestration of organic luminescent molecules(OLMs)within cage-based metal-organic frameworks(MOFs)as a dispersion platform has been developed to impede aggregation-caused quenching(ACQ).The homogenous encapsulation of distinct luminescent guests of different sizes and emissive behaviors in the cage structure of a MOF resulted in high fluorescent quantum yields of 44.8%for DAPI@NKU-110(DAPI=4',6-diamidino-2-phenylindole),65.4%for TPPA@NKU-110(TPPA=tris(4-(pyridin-4-yl)phenyl)amine),31.3%for R6G@NKU-110(R6G=Rhodamine 6G),and 58.3%for PY@NKU-110(PY=Pyronin Y),attributable to the confinement effect caused by the rigid cages of *** significantly,a positive correlation of the encapsulated quantity of OLMs with their concentration in the in-situ solvothermal reaction was unveiled by spectral analysis and utilized to facilely fabricate a white-light-emitting crystal material TPPA+R6G@*** material features a large crystal size on the millimeter-scale,broadband white emission,ideal CIE coordinates(0.33,0.34),and a high quantum yield(49.1%)when excited at 365 ***,such a strategy can be easily generalized to an abundance of other cage-based MOFs and a plentiful volume of OLMs for the future development of colorful,high performance luminescent materials.

关键词： Metal-organic frameworks Cage compounds Fluorescence Color tunability In-situ encapsulation

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Hypermethylation and aberrant expression of Wnt antagonist secreted frizzled-related protein 1 in gastric cancer

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World Journal of Gastroenterology 2007年第15期13卷 2214-2217页

作者： Cheng-Hai Zhao xian-Min bu Ning Zhang Department of Pathophysiology School of Basic Medicine China Medical University Shenyang 110001 Liaoning Province China Department of General Surgery the Second Affiliated Hospital China Medical University Shenyang 110004 Liaoning Province China

AIM： To identify the methylation of secreted frizzled-related protein 1 （SFRP1） in gastric cancer and to investigate the aberrant expression of SFRP1 and its correlation with the clinical pathological features of patients. METHODS： We determined SFRP1 methylation and SFRP1 mRNA expression in 3 gastric cancer cell lines SGC-7901, BGC-823, HGC-27, from 52 primary gastric cancer specimens and matched tumor adjacent tissue specimens by methylation-specific （MSP） PCR and RT-PCR respectively. Fisher＇s exact test was used to analyze the statistical association between clinical pathological data and aberrant expression of SFRP1. RESULTS： In 3 cancer cell lines, BGC-823 and HGC-27 had methylated SFRP1 and lost SFRP1 mRNA expression. After treatment of BGC-823 and HGC-27 with the demethylating agent, 5-aza-2′-deoxycytidine, SFRP1 was re-expressed. In 52 primary gastric cancer specimens and matched tumor adjacent tissue specimens, hypermethylation of SFRP1 was detected in 23 （44%） and 8 （15%） specimens respectively （x^2= 10.34, P 〈 0.01）. Loss of SFRP1 expression was detected in 17（33%） and 6 （12%） specimens respectively （x^2= 6.75, P 〈 0.01）. There was a significant correlation between SFRP1 hypermethylation and SFRP1 expression loss. SFRP1 expression was also correlated significantly with tumor stage and lymph node status, but not with patient sex, age and histological type. CONCLUSION： SFRP1 inactivation is a common and early event caused mainly by hypermethylation in gastric cancer. SFRP1 expression loss may be correlated with tumor metastasis in primary gastric cancer.

关键词： Secreted frizzled-related protein 1 Wnt Hypermethylation

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In-situ cation exchange enhances room temperature phosphorescence of a family of metal-organic frameworks

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Science China Chemistry 2022年第1期65卷 128-134页

作者： Rui Feng Zi-Ying Li Zhao-Quan Yao Zi-Ang Guo Yi-Nan Zhang Hao-xiang Sun Wei Li xian-he bu College of Chemistry State Key Laboratory of Elemento-Organic ChemistryNankai UniversityTianjin 300071China School of Materials Science and Engineering Tianjin Key Laboratory of Metal and Molecule-Based Material ChemistryNankai UniversityTianjin 300350China

The rational designability and chemical tunability of metal-organic frameworks(MOFs)are enabling tributes to efficaciously enhance their room temperature phosphorescence(RTP)performance.A family of stable anionic MOFs,[Zn_(2)(4,5-ImDC)_(2)]M_(2)(NKU-132,M=(CH_(3))_(2)NH_(2)or(CH_(2)CH_(3))_(2)NH_(2)),featuring significant RTP have been *** rational cation selection and in-situ replacement from dimethylammonium to diethylammonium,the phosphorescence lifetime is increased from 30.88 to126.3 ms,along with less sensitivity to *** work provides an anti-quenching and lifetime tuning example for RTP-MOFmaterials via facile host-guest chemistry.

关键词： metal-organic framework room temperature phosphorescence crystal engineering in situ regulation

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Donor-acceptor modulation of coordination polymers for effective photothermal conversion

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Science China Chemistry 2024年第12期67卷 4175-4183页

作者： Bo Zhang Xing-Wang Li Han Fang Chang-Tai Li Si-Jia Yu Mei-Hui Yu Ze Chang xian-he bu School of Materials Science and Engineering Nankai UniversityTianjin 300350China State Key Laboratory of Elemento-Organic Chemistry Nankai UniversityTianjin 300350China

The targeted construction of donor-acceptor(D-A)materials featuring efficient photothermal(PT)conversion properties has been an attractive but challenging ***,a new series of coordination polymers(CPs)featuring different PT performances were constructed with flexible linker 1,1′-Ferrocenedicarboxylic acid(FCA)and 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine(TPT)as acceptor and donor molecules including coronene and tetrathiafulvalene(TTF).Based on the flexible configurations of FCA ligand and the directing of donor dependent D-A interactions,the structures of TF-1 to TF-3 featuring distinctive dimension were obtained based on Cd(Ⅱ)ions for investigating the PT property in configurational perspectives.A systematic investigation of the PT properties of the CPs was ***,TF-3 exhibits the finest PT conversion effect under the irradiation of560 nm laser,while TF-2 shows optimal PT conversion under 808 nm laser irradiation required for biological PT therapy,illustrating the correlation between the structural and component features of the CPs and their PT ***,Zn(Ⅱ)as bio-friendly ion was utilized to construct hypotoxic TF-4 that reveals similar structure to that of TF-2 for potential ***(PDMS)patches doped with TF-4 exhibits considerable NIR PT conversion effect under808 nm,represented by the nearly 80℃temperature increased in 120 s for TF-4@PDMS patch(1.2 wt%)under 0.9 W cm^(-2)irradiation,the results of which herein indicate the potential of D-A CPs as versatile platform for the modulation of PT materials.

关键词： donor-acceptor material coordination polymer configuration modulation photothermal conversion charge transfer

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A Study on Modeling and Optimization of Memory Systems

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Journal of Computer Science & Technology 2021年第1期36卷 71-89页

作者： Jason Liu Pedro Espina xian-he Sun School of Computing and Information Sciences Florida International UniversityMiamiFL 33199U.S.A Department of Computer Science Illinois Institute of TechnologyChicagoIL 60616U.S.A

Accesses Per Cycle(APC),Concurrent Average Memory Access Time(C-AMAT),and Layered Performance Matching(LPM)are three memory performance models that consider both data locality and memory assess *** APC model measures the throughput of a memory architecture and therefore reflects the quality of service(QoS)of a memory *** C-AMAT model provides a recursive expression for the memory access delay and therefore can be used for identifying the potential bottlenecks in a memory *** LPM method transforms a global memory system optimization into localized optimizations at each memory layer by matching the data access demands of the applications with the underlying memory system *** three models have been proposed separately through prior *** paper reexamines the three models under one coherent mathematical *** specifically,we present a new memorycentric view of data *** divide the memory cycles at each memory layer into four distinct categories and use them to recursively define the memory access latency and concurrency along the memory *** new perspective offers new insights with a clear formulation of the memory performance considering both locality and ***,the performance model can be easily understood and applied in engineering *** such,the memory-centric approach helps establish a unified mathematical foundation for model-driven performance analysis and optimization of contemporary and future memory systems.

关键词： performance modeling performance optimization memory architecture memory hierarchy concurrent average memory access time

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I/O Acceleration via Multi-Tiered Data buffering and Prefetching

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Journal of Computer Science & Technology 2020年第1期35卷 92-120页

作者： Anthony Kougkas Hariharan Devarajan xian-he Sun Department of Computer Science Illinois Institute of TechnologyChicago 60616U.S.A

Modern High-Performance Computing(HPC)systems are adding extra layers to the memory and storage hierarchy,named deep memory and storage hierarchy(DMSH),to increase I/O *** hardware technologies,such as NVMe and SSD,have been introduced in burst buffer installations to reduce the pressure for external storage and boost the burstiness of modern I/O *** DMSH has demonstrated its strength and potential in ***,each layer of DMSH is an independent heterogeneous system and data movement among more layers is significantly more complex even without considering *** to efficiently utilize the DMSH is a subject of research facing the HPC ***,accessing data with a high-throughput and low-latency is more imperative than *** prefetching is a well-known technique for hiding read latency by requesting data before it is needed to move it from a high-latency medium(e.g.,disk)to a low-latency one(e.g.,main memory).However,existing solutions do not consider the new deep memory and storage hierarchy and also suffer from under-utilization of prefetching resources and unnecessary ***,existing approaches implement a client-pull model where understanding the application's I/O behavior drives prefetching *** towards exascale,where machines run multiple applications concurrently by accessing files in a workflow,a more data-centric approach resolves challenges such as cache pollution and *** this paper,we present the design and implementation of hermes:a new,heterogeneous-aware,multi-tiered,dynamic,and distributed I/O buffering *** enables,manages,supervises,and,in some sense,extends I/O buffering to fully integrate into the *** introduce three novel data placement policies to efficiently utilize all layers and we present three novel techniques to perform memory,metadata,and communication management in hierarchical buffering ***,we demonstrate the benefits

关键词： I/O buffering heterogeneous buffering layered buffering deep memory hierarchy burst buffers hierarchical data prefetching data-centric architecture

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Recent progress in metal–organic frameworks(MOFs)for electrocatalysis

Industrial Chemistry & Materials

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Industrial Chemistry & Materials 2023年第1期1卷 9-38页

作者： Cha Li Hao Zhang Ming Liu Fei-Fan Lang Jiandong Pang xian-he bu School of Materials Science and Engineering Smart Sensing Interdisciplinary Science CentreNational Institute for Advanced MaterialsTKL of Metal and Molecule-Based Material ChemistryNankai UniversityTianjin 300350P.R.China Haihe Laboratory of Sustainable Chemical Transformations Tianjin300192P.R.China State Key Laboratory of Elemento-Organic Chemistry College of ChemistryNankai UniversityTianjin 300071P.R.China

Electrocatalytic technology opens a new path to solve the existing problems in fossil fuel consumption and environmental pollution as well as efficient energy ***–organic frameworks(MOFs),a class of crystalline porous materials with high specific surface area,high porosity and customizable structures,have emerged as promising ***,their inherently low electrical conductivity and stability greatly hinder their further ***,strategies such as synthesizing two-dimensional conductive MOFs,designing unsaturated metal sites,and building MOF nanoarrays have been developed to enhance the conductivity and catalytic reaction transfer rates of MOFs,accompanied by the rational designs of MOFs for improving their *** this review,the applications of MOF-based electrocatalysts in the hydrogen evolution reaction(heR),hydrogen oxidation reaction(HOR),oxygen evolution reaction(OER),oxygen reduction reaction(ORR)and nitrogen reduction reaction(NRR)are presented in detail with the classification of monometallic MOFs,bimetallic MOFs,MOF-based composites and MOFs as *** addition,the relationship between the structure and performance is discussed through DFT calculations used in related ***,future challenges and application prospects of MOFs in electrocatalysis are highlighted.

关键词： Metal-organic frameworks Electrocatalyst Catalytic performance Catalysis Energy conversion

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