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Strong metal-support interactions between highly dispersed Cu^(+) species and ceria via mix-MOF pyrolysis toward promoted water-gas shift reaction

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Journal of Energy chemistry 2024年第4期91卷 475-483页

作者： Xiao-Chen Sun Xing-Chi Li Ze-Wei Xie Chen-Yue Yuan De-Jiu Wang Qian Zhang Xiao-Yu Guo Hao Dong Hai-Chao Liu Ya-Wen Zhang Beijing National Laboratory for molecular Sciences(BNLMS) State Key Laboratory of Rare Earth Materials Chemistry and ApplicationsPKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic ChemistryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Beijing National Laboratory for molecular Sciences(BNLMS) College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China Beijing National Laboratory for molecular Sciences(BNLMS) State Key Laboratory for Structural Chemistry of Stable and Unstable SpeciesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The modulation of metal-support interfacial interaction is significant but challenging in the design of high-efficiency and high-stability supported catalysts.Here,we report a synthetic strategy to upgrade Cu-CeO_(2)interfacial interaction by the pyrolysis of mixed metal-organic framework(MOF)structure.The obtained highly dispersed Cu/CeO_(2)-MOF catalyst via this strategy was used to catalyze water-gas shift reaction(WGSR),which exhibited high activity of 40.5μmolCOgcat^(-1).s^(-1)at 300℃and high stability of about 120 h.Based on comprehensive studies of electronic structure,pyrolysis strategy has significant effect on enhancing metal-support interaction and then stabilizing interfacial Cu^(+)species under reaction conditions.Abundant Cu^(+)species and generated oxygen vacancies over Cu/CeO_(2)-MOF catalyst played a key role in CO molecule activation and H2O molecule dissociation,respectively.Both collaborated closely and then promoted WGSR catalytic performance in comparison with traditio nal supported catalysts.This study shall offer a robust approach to harvest highly dispersed catalysts with finely-tuned metal-support interactions for stabilizing the most interfacial active metal species in diverse heterogeneous catalytic reactions.

关键词： Cu-based catalyst MOF derivative Water-gas shift reaction Metal-support interaction

Inhibitory effect of picroside Ⅱ on hepatocyte apoptosis

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Acta Pharmacologica Sinica 2005年第6期26卷 729-736页

作者： Hua GAO, Ya-wei ZHOU~2 college of chemistry and molecular engineering, Peking University, Beijing 100871, China college of chemistry and molecular engineering Peking University Beijing China

Aim: To investigate the influence of picroside on hepatocyte apoptosis and its mechanism. Methods: Morphological changes and quantification of apoptotic cells were determined under transmission electron microscopy and flow cytometry respectively. DNA fragmentation was visualized by agarose gel electrophoresis. Semi-quantitative reverse transcription-PCR (RT-PCR) was used to analyze the expression of bcl-2 and bax genes. The content of manganese-superoxide dismutase (SOD) in liver mitochondria was detected by the Marland method. The content of malonic aldehyde (MDA) and the protein level in liver tissue were determined by thiobarbituric acid colorimetry and Lowry method. Results: Picroside decreased the levels of alanine aminotransferase and aspartate aminotransferase in the serum resulting from acute-liver injured mice induced with D-GalN and LPS; it also reduced the content of MDA, and thus, enhanced the activity of SOD. Picroside 0 mg/kg was found to protect hepatocytes against apoptosis in a dose-dependent manner; it up-regulated the expression of bcl-2 genes, thus increased the bcl-2/bax ratio. Conclusion: Picroside 鈪an protect hepatocytes against injury and prevent hepatocytes from apoptosis. It might by upregulating the bcl-2 gene expression and antioxidation.

关键词： picroside Ⅱ hepatocytes apoptosis oxidative stress bcl-2 genes bax genes

Efficient and stable PtFe alloy catalyst for electrocatalytic methanol oxidation with high resistance to CO

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Journal of Energy chemistry 2024年第3期90卷 327-336,I0008页

作者： Qian Yang Sifan Zhang Fengshun Wu Lihua Zhu Guang Li Mingzhi Chen An Pei Yingliang Feng Jiangxi Provincial Key Laboratory of Functional molecular Materials chemistry College of Chemistry and Chemical EngineeringFaculty of Materials Metallurgy and ChemistryJiangxi University of Science and TechnologyGanzhou 341000JiangxiChina college of chemistry and Chemical engineering Xiamen UniversityXiamen 361005FujianChina

Direct methanol fuel cells(DMFC) are widely considered to be an ideal green energy conversion device but their widespread applications are limited by the high price of the Pt-based catalysts and the instability in terms of surface CO toxicity in long-term operation.Herein,the PtFe alloy nanoparticles(NPs) with small particle size(~4.12 nm) supported on carbon black catalysts with different Pt/Fe atomic ratios(Pt_(1)Fe_(2)/C,Pt_(3)Fe_(4)/C,Pt_(1)Fe_(1)/C,and Pt_(2)Fe_(1)/C) are successfully prepared for enhanced anti-CO poisoning during methanol oxidation reaction(MOR).The optimal atomic ratio of Pt/Fe for the MOR is 1:2,and the mass activity of Pt_(1)Fe_(2)/C(5.40 A mg_(Pt)^(-1)) is 13.5 times higher than that of conventional commercial Pt/C(Pt/C-JM)(0.40 A mg_(Pt)^(-1)).The introduction of Fe into the Pt lattice forms the PtFe alloy phase,and the electron density of Pt is reduced after forming the PtFe alloy.In-situ Fourier transform infrared results indicate that the addition of oxyphilic metal Fe has reduced the adsorption of reactant molecules on Pt during the MOR.The doping of Fe atoms helps to desorb toxic intermediates and regenerate Pt active sites,promoting the cleavage of C-O bonds with good selectivity of CO_(2)(58.1%).Moreover,the Pt_(1)Fe_(2)/C catalyst exhibits higher CO tolerance,methanol electrooxidation activity,and long-term stability than other Pt_(x)Fe_(y)/C catalysts.

关键词： Alloy catalyst PtFe Methanol oxidation In-situ FTIR CO resistance

Surface engineering of Li-and Mn-rich layered oxides for superior Li-ion battery

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Tungsten 2024年第1期6卷 259-268页

作者： Lu-Xiang Ma Tian-Dong Chen Chun-Xi Hai Sheng-De Dong Xin He Qi Xu Hang Feng AXin Ji-Tao Chen Yuan Zhou college of Materials and chemistry and Chemical engineering Chengdu University of TechnologyChendu 610000China Qinghai Building and Materials Research Co. LtdXining 810000China Beijing National Laboratory for molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The Li-and Mn-rich layered oxides(R-LNCM)are considered as promising cathode materials for high-energy density lithium-ion batteries(LIBs).However,the interface side reaction aggravates the voltage and capacity fading between cathode material and electrolyte at high voltage,which severely hinders the practical application of LIB s.Herein,lithium polyacrylate(LiPAA)as the binder and coating agent is applied to suppress the voltage and capacity fading of R-LNCM electrode.The flexible LiPAA layers with high elasticity are capable of impeding cathode cracks on the particle surface via mechanical stress relief.Thus,superior voltage and capacity fading suppression on R-LNCM electrode is finally achieved.As a result,LiPAA-R-LNCM cathode exhibits a remarkable specific capacity of 186 mA·h·g^(-1)with~73%retention at 1℃after 200cycles.Further,the corresponding average discharge potential is maintained to~3.1 V with only~0.4 V falling.

关键词： LiPAA interphase layer Interface side reaction Cathode cracks Capacity and voltage fading suppression Liand Mn-rich cathode

Micelle-directed self-assembly of single-crystal-like mesoporous stoichiometric oxides for high-performance lithium storage

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National Science Review 2024年第4期11卷 195-205页

作者： Yanhua Wan Changyao Wang Xingmiao Zhang Yang Yin Mengmeng Liu Bing Ma Linlin Duan Yuzhu Ma Wei Zhang Changlin Zheng Dongliang Chao Fei Wang Yongyao Xia Wei Li Department of chemistry Laboratory of Advanced Materials Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials State Key Laboratory of Molecular Engineering of Polymers College of Chemistry and Materials ScienceFudan University State Key Laboratory of Surface Physics and Department of Physics Fudan University

Due to their uncontrollable assembly and crystallization process,the synthesis of mesoporous metal oxide single crystals remains a formidable challenge.Herein,we report the synthesis of single-crystal-like mesoporous Li2TiSiO5by using soft micelles as templates.The key lies in the atomic-scale self-assembly and step-crystallization processes,which ensure the formation of single-crystal-like mesoporous Li2TiSiO5microparticles via an oriented attachment growth mechanism under the confinement of an in-situ formed carbon matrix.The mesoporous Li2TiSiO5anode achieves a superior rate capability(148 mAh g-1at5.0 A g-1) and outstanding long-term cycling stability(138 mAh g-1after 3000 cycles at 2.0 A g-1) for lithium storage as a result of the ultrafast Li+diffusion caused by penetrating mesochannels and nanosized crystal frameworks（5-10 nm）.In comparison,bulk Li2TiSiO5exhibits poor rate capability and cycle performance due to micron-scale diffusion lengths.This method is very simple and reproducible,heralding a new way of designing and synthesizing mesoporous single crystals with controllable frameworks and chemical functionalities.

关键词： mesoporous materials micelles single-crystal-like Li2TiSiO5 lithium-ion batteries

Nanomaterial Assisted Exosome Analysis Using Mass Spectrometry

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Chemical Research in Chinese Universities 2024年第2期40卷 237-254页

作者： ZHANG Yi ZHOU Bokai LI Qiuning JIN Mingshi BAI Yu Beijing National Laboratory for molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871P.R.China Department of chemistry Yanbian UniversityYanji133002P.R.China

Exosomes,extracellular vesicles(EVs)that play crucial roles in biological processes,have emerged as attractive targets for noninvasive disease diagnosis and monitoring.Mass spectrometry(MS)offers high sensitivity,high throughput,and excellent qualification and quantification capacity,which is the ideal approach for exosome analysis.Nanomaterials’unique physiochemical properties,controllable morphology,and large surface area make them promising in biological sample pretreatment and detection.They contributed diverse functions to the exosome MS analysis,encompassing substrates for exosome isolation and cargos enrichment,matrices for laser desorption/ionization(LDI),read-out signals and supporters for signal amplification strategies,etc.In this review,recent progress in the applications of nanomaterial in the exosome MS analysis was summarized and a comprehensive discussion on the challenges and perspectives was proposed for the development of an advancing analysis approach of exosomes for the accurate diagnosis and monitoring of diseases.

关键词： Exosome Nanomaterial Enrichment Matrix Mass spectrometry

Increase of chiral sensing ability in host-guest chemistry by magnetic anisotropy

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Science China chemistry 2024年第8期67卷 2775-2782页

作者： Jia-Liang Chen Bin Li Feng Yang Tiesheng Shi Xun-Cheng Su State Key Laboratory of Elemento-organic chemistry Tianjin Key Laboratory of Biosensing and Molecular RecognitionCollege of Chemistry Nankai University college of chemistry Chemical Engineering and Materials Science Zaozhuang University

Enantiomeric molecules generally play distinct functions in chemistry, biology, and pharmacology. Similar physical and chemical properties of chiral analytes lay difficulty in discrimination and quantification of the enantiomers. We report herein an efficient approach of increasing the chiral sensing ability of β-cyclodextrin(β-CD), a widely used host molecule, in the hostguest chemistry by magnetic anisotropy. A rigid and chiral lanthanide binding tag was attached to the β-CD to amplify the changes of nuclear magnetic resonance(NMR) signals in the host-guest recognition process. The installation of the paramagnetic lanthanide ion in β-CD greatly enhances the enantiomeric discrimination up to 30-fold in comparison with the diamagnetic β-CD reference. In addition, the magnitude of the paramagnetic effects is tunable according to the diverse range of paramagnetic strength of the lanthanide series. The reported method significantly increases the chiral sensing ability of β-CD, which can be applied to other host molecules. The transferred paramagnetic effects, pseudocontact shifts(PCSs) and paramagnetic relaxation enhancements(PREs), from the host to the guest molecules, are valuable structural restraints to determine the absolute stereochemistry of the chiral analytes. The strategy does not need modification of the analytes and is complementary to the reported analytical methods that rely on the functionalization of the chiral analytes.

关键词： chiral recognition host-guest chemistry lanthanide ions magnetic anisotropy nuclear magnetic resonance

NIR-IIb-triggered photodynamic therapy combined with chemotherapy platform based on rare-earth-doped nanoparticles

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Rare Metals 2024年第7期43卷 3220-3231页

作者： Zhuo Tu Yong Wan Juan Ge Chen-Chen Li Tao Liang Zhen Li college of Health Science and engineering College of Chemistry and Chemical EngineeringHubei University

Photodynamic therapy（PDT）,with high spatiotemporal selectivity,minimal side effects and less drug resistance,has emerged as a promising approach for the treatment of cancer.However,inadequate penetration depth and poor efficacy seriously restrict its practical application.To address these challenges,we developed a combined therapy platform（RENP@C/D-FA） based on rare-earth-doped nanoparticles（RENPs） with a structure of NaErF4:Tm（0.5%）@NaYF4,on which photosensitizer Ce6（chlorin e6） and chemo-therapeutic drug（DOX）(doxorubicin) were loaded by encapsulating with an amphiphilic polymer distearoyl phosphatidylethanolamine-polyethylene glycol-folic acid（DSPE-PEG-FA）.RENPs with NaErF4as the matrix possess multiple excitation/emission peaks,enabling activation of PDT under near-infrared-Ⅱb（NIR-Ⅱb,1500-1700 nm） excitation and luminescence imaging in NIR-Ⅱb region by absorbing 808 nm near-infrared photons.Furthermore,DOX can be selectively released in the acidic microenvironment of tumors.Benefiting from the tumor targeting capability of folic acid,this platform can successfully ablate tumor cells and inhibit tumor growth by combining PDT and chemotherapy.This innovative approach holds great promise as a powerful tool for cancer treatment,showing the potential to revolutionize PDT.

关键词： Photodynamic therapy Rare-earth-doped nanoparticles NIR-IIb Chemotherapy Combined therapy

SYNTHESIS AND CHARACTERIZATION OF A NOVEL BLUE LIGHT EMITTING ROD-COIL DIBLOCK OLIGOMER

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Chinese Journal of Polymer Science 2002年第5期20卷 401-407页

作者： Lifang Yang Haifeng He Hongqing Cao Xinhua Wan Qi-feng Zhou Department of Polymer Science & engineering college of chemistry & molecular engineering Peking University Beijing 100871, China Department of Polymer Science & engineering College of Chemistry & Molecular Engineering Peking University 北京 100871 Department of Polymer Science & engineering College of Chemistry & Molecular Engineering Peking University 北京 100871

Four new rod-coil diblock molecules, which had well-defined para-phenylene oligomers (PPP, from biphenyl to quinquephenyl) as rigid segments and poly(ethylene oxide) (PEO, M-w ca. 750) as flexible segments, were synthesized. The chemical structure and the number of repeating unit in PEO coil and PPP rod were characterized by H-1-NMR and MALDI-TOF mass spectrometry. The diblock oligomers showed good solubility in common organic solvents and aggregated in water as characterized by a blue shift in UV-vis absorption spectra, a red shift in emission spectra, quenching of the fluorescence and formation of the microfibrilla and fractal-like structures. The formation of different supramolecular structures meant that this effort might lead to commercial important highly organized functional materials.

关键词： rod-coil diblock oligomer MALDI-TOF mass spectrometry microfibrilla aggregate fractal-like pattern