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Efficient epoxidation of propylene over non-noble nickel-based catalyst promoted by alkali metals

Science china Chemistry 2024年第11期67卷 3697-3705页

作者： Wenqian Li Wanting Li Xinxin Cao Longfei Chen Yibo Qin Yanfeng Zhu Yanfei Zhang Gai Miao Lingzhao Kong Jiong Li Xinqing Chen State Key Laboratory of Low Carbon Catalysis and Carbon Dioxide Utilization CAS Key Laboratory of Low-carbon Conversion Science and EngineeringShanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210China University of Chinese Academy of Sciences Beijing 100049China School of Environmental Science and Engineering Suzhou University of Science and TechnologySuzhou 215009China Shanghai Synchrotron Radiation Facility Zhangjiang National LabShanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201210China

The application of non-noble metal catalysts in the catalytic direct gas-phase epoxidation of propylene with H2and O2to produce propylene oxide is valuable and challenging. The introduction of alkali metal promoters is one of the effective methods to improve the catalytic activity of catalysts. Herein, a series of alkali metal(Li, Na, K, Rb, and Cs)-promoted Ni/TS-1 catalysts were prepared to deeply understand the effect of alkali metals on the structure-activity relationship for gas-phase epoxidation of propylene. Among them, the Na-Ni/TS-1 catalyst exhibits the highest catalytic activity(propylene conversion of 7.35% and PO formation rate of 157.9 g h^(-1)kg_(cat)^(-1)) and the best stability(long-term stability exceeding 140 h at 200 ℃). X-ray absorption and photoelectron spectroscopy revealed that the electronic structure of Ni can be tuned by the addition of alkali metal ***3-TPD-MS, CO_(2)-TPD-MS, and C_(3)H_(6)-TPD-MS results indicate that the acidity of the catalyst can also be adjusted by the introduction of alkali metal, whereas the Na-Ni/TS-1 catalyst exhibits the strongest C_(3)H_(6) adsorption capacity. Thus, the suitable acid-base properties, unique electronic properties of Ni species, and the strongest propylene adsorption capacity resulted in improved propylene gas-phase epoxidation activity of Na-Ni/TS-1 catalyst. This study not only provides a new strategy for the practical application of nickel-based catalysts in the gas-phase epoxidation of propylene but also provides insights into the promoting effect of alkali metals.

关键词： propylene epoxidation Ni/TS-1 catalyst alkali metal precipitating agents

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Migration and distribution characteristics of soil heavy metal(loid)s at a lead smelting site

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Journal of Environmental Sciences 2024年第1期135卷 600-609页

作者： Chuxuan Li Mu Li Jiaqing Zeng Shanxin Yuan Xinghua Luo Chuan Wu Shengguo Xue School of Metallurgy and Environment Central South UniversityChangsha 410083China Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution Central South UniversityChangsha 410083China

Heavy metal(loid)s contamination is a constant issue at smelting *** is essential to investigate the spatial distribution and migration characteristics of heavy metal(loid)s in the soil for environmental management and remediation strategies of non-ferrous smelting *** this study,203 soil samples from 57 sites were collected in a typical lead smelting *** findings demonstrated that there were significant Pb,Zn,Cd,and As contamination in soil *** spatial distribution of heavy metal(loid)s showed strong spatial heterogeneity,the contaminated soil areas of Pb,As,Cd,and Zn were 99.5%,98.9%,85.3%,and 72.4%,***,Cd,and As contamination of the soil reached a depth of 5 m,which migrated from the surface to deep soil *** leaching contents of Zn,Pb,and As decreased obviously in 3-4 m soil layer,but the leaching content of Cd was still high,which indicated the high migration of *** the increase of depth,the proportion of acid soluble fraction of heavy metal(loid)s decreased,and the residual fraction *** acid soluble fraction of Cd accounted for a higher proportion,and As mainly existed in reducible and residual fractions in *** to the calculation of the migration factor,the migration of heavy metal(loid)s in soils were ordered as Cd>Zn>Pb>*** outcomes are advantageous for risk reduction and site remediation for non-ferrous metal smelting sites.

关键词： Smelting sites Heavy metal(loid)s Spatial distribution Chemical speciation Migration characteristics

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Laboratory observation of electron energy distribution near three-dimensional magnetic nulls

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Plasma Science and Technology 2024年第3期26卷 46-52页

作者：何任川徐田超杨肖易肖池阶张祖煜袁瑞鑫王晓钢郭志彬余修铭盖跃 State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871People's Republic of China Department of Physics Harbin Institute of TechnologyHarbin 150001People's Republic of China

The acceleration of electrons near three-dimensional(3D)magnetic nulls is crucial to the energy conversion mechanism in the 3D magnetic reconnection *** explore electron acceleration in a 3D magnetic null topology,we constructed a pair of 3D magnetic nulls in the PKU Plasma Test(PPT)device and observed acceleration of electrons near magnetic *** study measured the plasma floating potential and ion density profiles around the 3D magnetic *** potential wells near nulls may be related to the energy variations of electrons,so we measured the electron distribution functions(EDFs)at different spatial *** axial variation of EDF shows that the electrons deviate from the Maxwell distribution near magnetic *** scanning probes that can directionally measure and theoretically analyze based on curve fitting,the variations of EDFs are linked to the changes of plasma potential under 3D magnetic null *** kinetic energy of electrons accelerated by the electric field is 6 eV(v_(e)~7v_(Alfvén-e))and the scale of the region where accelerating electrons exist is in the order of serval electron skin depths.

关键词： electron acceleration EEDF 3D magnetic null magnetic reconnection

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Highly enhanced removal of Cr(VI)by nZVI in presence of myo-inositol hexakisphosphate:The depassivation performance and multiple electron transfer mechanisms

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Journal of Environmental Sciences 2025年第4期150卷 349-361页

作者： Cheng Wang Shuijing Zhou Feng Jiang Yupeng Yan Xiaoming Wang Hui Yin Wenfeng Tan Xionghan Feng Key Laboratory of Arable Land Conservation(Middle and Lower Reaches of Yangtze River) Ministry of Agriculture and Rural Affairs of the People’s Republic of ChinaCollege of Resources and EnvironmentHuazhong Agricultural UniversityWuhan 430070China Key Laboratory of Poyang Lake Basin Agricultural Resource and Ecology of Jiangxi Province College of Land Resource and EnvironmentJiangxi Agricultural UniversityNanchang 330045China

The capability of traditional ligand in countering rapid passivation on nanoscale zero-valent iron(nZVI)surface is inadequate,and the precise electron transfer mechanism remains *** this study,we reported that myo-inositol hexakisphosphate(IHP),a redox-inactive organophosphorus in soil,could highly enhance Cr(VI)reduction and immobilization in comparison with typical ligands(TPP,EDTA,oxalate and phosphate).And the effects of IHP concentration,Cr(VI)concentration and initial pH were systematically *** Kedge XANES and XPS analysis revealed that Cr(III)was the exclusive form in solid products regardless of IHP *** of ATR-FTIR and FESEM inferred that IHP was adsorbed on nZVI surface via inner-sphere complexation,thus averting encapsulation of[Fe,Cr](OH)_(3)coprecipitate and impeding solid particles ***,IHP expedited the production of surface-bound Fe(II),primarily attributable to the interaction between nZVI and *** surface-bound Fe(II)species played a pivotal role in Cr(VI)*** analysis unveiled that IHP lowered redox potential of Fe(III)/Fe(II),thereby facilitating reaction between Fe(II)and Cr(VI),whereas inhibited direct electron transfer from nZVI core to Cr(VI).Our findings proposed a novel potential ligand for alleviating nZVI passivation in Cr(VI)removal and deepened our understanding in the process of electron transfer.

关键词： Cr(VI)removal nZVI Myo-inositol hexakisphosphate Depassivation Electron transfer

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Unlocking efficient energy storage via regulating ion and electron-active subunits:an(SbS)_(1.15)TiS_(2)superlattice for large and fast Na^(+)storage

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Science china Chemistry 2024年第1期67卷 336-342页

作者： Baixin Peng Tianxun Cai Shaoning Zhang Yuqiang Fang Zhuoran Lv Yusha Gao Fuqiang Huang State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Physical Science and Technology ShanghaiTech UniversityShanghai 200031China Beijing National Laboratory for Molecular Sciences State Key Laboratory of Rare Earth Materials Chemistry and ApplicationsCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Alloying-type metal sulfides with high sodiation activity and theoretical capacity are promising anode materials for high energy density sodium ion ***,the large volume change and the migratory and aggregation behavior of metal atoms will cause severe capacity decay during the charge/discharge ***,a robust and conductive TiS_(2)framework is integrated with a high-capacity SbS layer to construct a single phase(SbS)_(1.15)TiS_(2)superlattice for both high-capacity and fast Na^(+)*** metallic TiS_(2)sublayer with high electron activity acts as a robust and conductive skeleton to buffer the volume expansion caused by conversion and alloying reaction between Na+and SbS ***,high capacity and high rate capability can be synergistically realized in a single phase(SbS)_(1.15)TiS_(2)*** novel(SbS)_(1.15)TiS_(2)anode has a high charge capacity of 618 mAh g^(-1)at 0.2 C and superior rate performance and cycling stability(205 mAh g^(-1)at 35 C after 2,000 cycles).Furthermore,in situ and ex situ characterizations are applied to get an insight into the multi-step reaction *** integrity of robust Na-Ti-S skeleton during(dis)charge process can be *** superlattice construction idea to integrate the Na^(+)-active unit and electron-active unit would provide a new avenue for exploring high-performance anode materials for advanced sodium-ion batteries.

关键词： (SbS)_(1.15)TiS_(2) sulfides sodium ion battery superlattice fast-charging

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Determination of 28 food safety risk factors in novel foods by ultra-high-performance liquid chromatographyquadrupole/Orbitrap high-resolution mass spectrometry

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Food Quality and Safety 2025年第1期9卷 115-128页

作者： Sufang Fan Xiaowei Ren Guohua Shi Limin Zhao Junmei Ma Qiang Li Di Wen Yan Zhang Hebei Food Safety Key Laboratory Key Laboratory of Special Food Supervision TechnologyState Administration for Market RegulationHebei Engineering Research Center for Special Food Safety and HealthHebei Food Inspection and Research InstituteShijiazhuangChina Hebei Key Laboratory of Forensic Medicine College of Forensic MedicineHebei Medical UniversityShijiazhuangChina

An analytical method was established for the determination of 24 food safety risk factors(18 heterocyclic aromatic amines and six mycotoxins)in synthetic meat and synthetic protein samples,and four microcystins in microalgae samples using ultra-high-performance liquid chromatographyquadrupole/Orbitrap high-resolution mass spectrometry(UPLC-Q/Orbitrap HRMS).The novel synthetic food was extracted using 50%methanol solution and purified with 3 mL of n-hexane saturated with 50%(volume fraction)methanol *** the microalgae samples,extraction was performed with 80%(volume fraction)acetonitrile solution and purified using a PRiME HLB solid-phase extraction *** ACQUITY HSS T3 column(100 mm×2.1 mm,1.8μm)was used for analyte separation,with 5 mmol/L ammonium acetate containing 0.01%(volume fraction)formic acid and methanol selected as the mobile *** elution was *** acquisition was conducted in both positive and negative modes in full-scan data-dependent secondary scan mode(full MS-ddMS2).Matrix-matched standards were employed for quantification in the external standard ***,mzVault and TraceFinder were used to establish a screening database for 28 food safety risk *** results showed that the relative deviation of the exact mass of 28 food safety risk factors was less than 5×10^(-6),with good linearity in the range of 1-100μg/kg,and a correlation coefficient(r^(2))of≥*** detection limit ranged from 0.5 to 4μg/kg,and the quantification limit ranged from 1 to 10μg/*** method recovery ranged from 70.0%to 119.6%with relative standard deviations ranging from 0.4%to 14.6%(n=6).The method is simple,sensitive,accurate,and suitable for rapid screening of 28 food safety risk factors in novel foods.

关键词： Ultra-high-performance liquid chromatography-quadrupole/Orbitrap high-resolution mass spectrometry(UPLC-Q/Orbitrap HRMS) novel foods food safety risk factors database

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Fabrication of Zn-0.5Mn-0.05 Mg Micro-Tube with Suitable Strength and Ductility for Vascular Stent Application

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Acta Metallurgica Sinica(English Letters) 2025年第2期38卷 327-337页

作者： Dongfang Lou Mingda Zhang Yuping Ren Hongxiao Li Gaowu Qin Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China Institute of Materials Intelligent Technology Liaoning Academy of MaterialsShenyang 110004China Research Center for Metallic Wires Northeastern UniversityShenyang 110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

Biodegradable Zn alloys are a hot topic in the biodegradable vascular stent materials,the study on preparing Zn alloys microtubes for vascular stent is still insufficient and none of the tubes could well meet the mechanical requirement by *** this study,we fabricate Zn-0.5Mn-0.05 Mg microtube with outer diameter of 3.5 mm and wall thickness of 0.2 mm by five passes three-roller *** mechanical properties of the microtube are 277±2.9 MPa,330±3.3 MPa and 39.8±5.25%for the yield tensile strength(YTS),ultimate tensile strength(UTS)and break elongation,respectively,which well satisfies the requirements of the vascular *** leading factors to the variations of the mechanical property are texture evolution,grain size refinement and microstructure uniformity during the rolling process,and the main deformation mechanisms are twinning and dislocation *** a result of the dynamic recrystallization,the grain size decreases obviously and the microstructure gets more uniform as the rolling pass *** texture gradually changes from a basal texture<0110>‖ED(extrusion direction)for the as-extruded tube blank to deformation texture<0001>‖RD(rolling direction)and non-basal texture<0221>‖RD for the 5-pass rolled microtube.

关键词： Zn alloys Microtube Microstructure Mechanical property Three-roller rolling

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Effect of Al_(2)O_(3)/SiO_(2) mass ratio and CaO content on viscosity and structure of slag for pyrometallurgical processing of spent automotive catalysts

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Journal of Iron and Steel research International 2024年第3期31卷 608-621页

作者： Zhe Wang Qi-long Wei Cheng-bin Shi Zhan-cheng Guo State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

The effect of Al_(2)O_(3)/SiO_(2) mass ratio and CaO content on the viscosity and structure of the CaO-Al_(2)O_(3)-SiO_(2)-6MgO-1.5ZrO_(2)-1.5CeO_(2) slag was *** results show that with the increase in Al_(2)O_(3)/SiO_(2) mass ratio,the viscous flow units within the slag gradually change from Si-O-Si to Al-O-Al and ***,the substitution of Al_(2)O_(3) for SiO_(2) leads to the transformation of Si-O bonds towards weaker Al-O bonds,which weaken the bond strength of the aluminosilicate networks,thus leading to a decrease in the viscosity of *** increase in CaO content effectively promotes the depolymerization of the aluminosilicate networks,resulting in a significant decrease in the viscosity of the *** slag with Al_(2)O_(3)/SiO_(2) of 0.7-1.5 and CaO of 30 wt.%shows promise as the reference slag system for the Fe-collection smelting of spent automotive catalysts due to its good comprehensive performance.

关键词： Aluminosilicate slag Al_(2)O_(3)/SiO_(2)mass ratio CaO content Viscosity Slag structure

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Determining the tilt of the Raman laser beam using an optical method for atom gravimeters

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Chinese Physics B 2024年第12期33卷 264-268页

作者： Hua-Qing Luo Yao-Yao Xu Jia-Feng Cui Xiao-Bing Deng Min-Kang Zhou Xiao-Chun Duan Zhong-Kun Hu MOE Key Laboratory of Fundamental Physical Quantities Measurement&Hubei Key Laboratory of Gravitation and Quantum Physics PGMF and School of PhysicsHuazhong University of Science and TechnologyWuhan 430074China Oak Ridge National Laboratory TennesseeUSA

The tilt of a Raman laser beam is a major systematic error in precision gravity measurement using atom *** conventional approach to evaluating this tilt error involves modulating the direction of the Raman laser beam and conducting time-consuming gravity measurements to identify the error *** this work,we demonstrate a method to expediently determine the tilt of the Raman laser beam by transforming the tilt angle measurement into characterization of parallelism,which integrates the optical method of aligning the laser direction,commonly used in freely falling corner-cube gravimeters,into an atom gravimeter.A position-sensing detector(PSD)is utilized to quantitatively characterize the parallelism between the test beam and the reference beam,thus measuring the tilt precisely and *** carefully positioning the PSD and calibrating the relationship between the distance measured by the PSD and the tilt angle measured by the tiltmeter,we achieved a statistical uncertainty of less than 30μrad in the tilt ***,we compared the results obtained through this optical method with those from the conventional tilt modulation method for gravity *** comparison validates that our optical method can achieve tilt determination with an accuracy level of better than 200μrad,corresponding to a systematic error of 20μGal in g *** work has practical implications for real-world applications of atom gravimeters.

关键词： atom interferometer absolute gravimeter precision measurement tilt of Raman laser

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A Neuro Metasurface Mode-Router for Fiber Mode Demultiplexing and Communications

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Engineering 2025年第2期45卷 88-96页

作者： Yu Zhao Huijiao Wang Zile Li Tian Huang Chao Yang Ying Qiu Yuhan Gong Zhou Zhou Congling Liang Lei Yu Jin Tao Shaohua Yu Guoxing Zheng Electronic Information School&School of Microelectronics Wuhan UniversityWuhan 430072China Peng Cheng Laboratory Shenzhen 518055China State Key Laboratory of Optical Communication Technologies and Networks China Information Communication Technologies Group Corporation(CICT)Wuhan 430074China Wuhan Institute of Quantum Technology Wuhan 430206China

Advancements in mode-division multiplexing(MDM)techniques,aimed at surpassing the Shannon limit and augmenting transmission capacity,have garnered significant attention in optical fiber communica-tion,propelling the demand for high-quality multiplexers and ***,the criteria for ideal-mode multiplexers/demultiplexers,such as performance,scalability,compatibility,and ultra-compactness,have only partially been achieved using conventional bulky devices(e.g.,waveguides,grat-ings,and free space optics)—an issue that will substantially restrict the application of MDM ***,we present a neuro-meta-router(NMR)optimized through deep learning that achieves spatial multi-mode division and supports multi-channel communication,potentially offering scalability,com-patibility,and *** MDM communication system based on an NMR is theoretically designed and experimentally demonstrated to enable simultaneous and independent multi-dataset transmission,showcasing a capacity of up to 100 gigabits per second(Gbps)and a symbol error rate down to the order of 104,all achieved without any compensation technologies or correlation *** work presents a paradigm that merges metasurfaces,fiber communications,and deep learning,with potential applications in intelligent metasurface-aided optical interconnection,as well as all-optical pat-tern recognition and classification.

关键词： Metasurfaces Deep learning Mode-division multiplexing Fiber communication

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