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Enhancing O_(2)electroreduction to H_(2)O on Ag/MnO_(2)-CHNTs by boosting a four-electron catalytic pathway

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Green Energy & Environment 2023年第5期8卷 1437-1449页

作者： Aiai Zhang Yang Liu Caixia Li Lei Xue Ze Liu Jinfang Wu Shanghong Zeng inner mongolia key laboratory of Chemistry and Physics of Rare Earth materials School of Chemistry and Chemical EngineeringInner Mongolia UniversityHohhot010021China

A fundamental question in the oxygen reduction reaction(ORR)is how to rationally control the electrocatalytic selectivity for opening a four-electron reaction ***,it still lacks direct experimental evidence to understand the reaction *** work unravels that Ag nanoparticles and carbonizing halloysite nanotubes(CHNTs)can trigger the construction of oxygen defects in the MnO_(2),which contribute to the generation of active *** Ag/MnO_(2)-CHNTs delivers a superior activity toward ORR with high onset potential,half-wave potential,diffusion-limited current density,long-term durability and methanol *** importantly,combined with density functional theory calculations,triggering manganese dioxide defects upon the introduction of Ag nanoparticles and CHNTs can alter the electrocatalytic pathway from a two-electron to a direct four-electron direction for ORR,which is the nature of enhanced ORR *** on the analysis of the results,this finding points out a very effective approach for exploring catalysts with the improved performance and durability for ORR reaction.

关键词： Manganese dioxide defects Ag/MnO_(2)-CHNTs Reaction mechanism Oxygen reduction reaction

Activity and deactivation behavior of Au/LaMnO_3 catalysts for CO oxidation

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Journal of Rare Earths 2011年第3期29卷 213-216页

作者：贾美林李旭照日格图沈岳年李云霞 College of Chemistry & Environmental Science Key Laboratory of Physics and Chemistry of Functional MaterialsInner Mongolia Normal UniversityHohhot 010022China College of Chemistry and Chemical Engineering Inner Mongolia UniversityHohhot 010021China

Perovskite oxide LaMnO3 was prepared by sol-gel method and the nanosize Au/LaMnO3 catalyst was prepared by deposition-precipitation（DP） method in the *** of the catalyst sample was made by X-ray diffractometer（XRD）,atom absorption spectra（AAS） and X-ray photoelectron spectroscopy（XPS） instrumental *** activity,long-term stability and the reasons for deactivation of the gold catalyst in CO oxidation were *** experiment results demonstrated that the Au/LaMnO3 catalyst exhibited high stability in the ambient storage ***,the gradual decrease in initial activity during 100 h reaction was still observed,which could be ascribed to the aggregation of gold particles and the transfer from gold ion to the metal gold.

关键词： deactivation gold catalyst Au/LaMnO3 CO oxidation long-term stability rare earths

Exchange bias for ferromagnetic/antiferromagnetic bilayers with the uniaxial anisotropy being misaligned with the exchange anisotropy

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Science China(Physics,Mechanics & Astronomy) 2009年第12期52卷 1885-1892页

作者： BAI YuHao1 & YUN GuoHong1,2 1 College of Physical Science and Technology,inner mongolia University,Hohhot 010021,China 2 key laboratory of Physics and Chemistry of functional materials,College of Physics and Electronic Information,inner mongolia Normal University,Hohhot 010022,China College of Physical Science and Technology Inner Mongolia University Hohhot China key laboratory of Physics and Chemistry of functional materials College of Physics and Electronic Information Inner Mongolia Normal University Hohhot China

Using the principle of minimal energy and S-W model,the exchange bias for ferromagnetic/antiferro-magnetic bilayers has been investigated when the uniaxial anisotropy is misaligned with the exchange anisotropy. According to the relation between the energy of the bilayer and the orientation of ferro-magnetic magnetization,it is found that the bilayer will be in the monostable state or bistable state when the external field is absent in the initial magnetization state. The monostable state or bistable state of the bilayer,which determines the angular dependence of exchange bias directly,is controlled by the competition between the exchange anisotropy and uniaxial anisotropy. When the applied field is parallel to the intrinsic easy axes and intrinsic hard axes,one of the switching fields of the hysteresis loop shows an abrupt change,while the other keep continuous by analyzing the magnetization reversal processes. Consequently,the exchange bias field and the coercivity will show a jump phenomenon. The numerical calculations indicate that both the magnitude and direction of the exchange anisotropy will significantly affect the angular dependence of exchange bias. The jump phenomenon of exchange bias is an intrinsic property of the bilayer,which is dependent on the interfacial exchange-coupling constant,the orientation of the exchange anisotropy,the thickness and uniaxial anisotropy constant of the ferromagnetic layer.

关键词： monostable state bistable state intrinstic easy axis intrinstic hard axis switching field

Supramolecular electrostatic self-assembly of mesoporous thin-walled graphitic carbon nitride microtubes for highly efficient visible-light photocatalytic activities

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Journal of Energy Chemistry 2020年第10期29卷 214-223页

作者： Yilin Chen Xingchen He Dongsheng Guo Yanqin Cai Jingling Chen Yun Zheng Bifen Gao Bizhou Lin Fujian key laboratory of photoelectric functional materials College of Materials Science and EngineeringHuaqiao UniversityXiamen 361021FujianChina

For efficient solar energy conversion,the morphology engineering of hollow graphitic carbon nitride(gC3 N4)is one of the promising approachs benefiting from abundant exposed active sites and short photocarrier transport distances,but is difficult to control on account of easy structural ***,a facile supramolecular electrostatic self-assembly strategy has been developed for the first time to fabricate mesoporous thin-walled g-C3N4 microtubes(mtw-CNT)with shell thickness of ca.13 *** morphological control of g-C3N4 enhances specific surface area by 12 times,induces stronger optical absorption,widens bandgap by 0.18 e V,improves photocurrent density by 2.5 times,and prolongs lifetimes of charge carriers from bulk to surface,compared with those of bulk *** a consequence,the transformed g-C3N4 exhibits the optimum photocatalytic H2-production rate of 3.99 mmol·h^-1·g^-1(λ>420 nm)with remarkable apparent quantum efficiency of 8.7%(λ=420±15 nm)and long-term ***,mtw-CNT also achieves high photocatalytic CO2-to-CO selectivity of 96%(λ>420 nm),much better than those on the most previously reported porous g-C3N4 photocatalysts prepared by the conventional hard-templating and soft-templating methods.

关键词： Graphitic carbon nitride Thin wall Mesoporous microtube H2 production CO2 reduction Photocatalysis

Insight to the enhanced microwave absorption of porous N-doped carbon driven by ZIF-8:Competition between graphitization and porosity

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International Journal of Minerals,Metallurgy and materials 2023年第3期30卷 474-484页

作者： You Zhou Hongpeng Wang Dan Wang Xianfeng Yang Hongna Xing Juan Feng Yan Zong Xiuhong Zhu Xinghua Li Xinliang Zheng School of Physics State Key Laboratory of Photoelectric Technology and Functional MaterialsNorthwest UniversityXi’an 710127China

Porous carbon-based materials are promised to be lightweight dielectric microwave *** understanding the influence of graphitization grade and porous structure on the dielectric parameters is urgently ***,utilizing the low boiling point of Zn,porous N-doped carbon was fabricated by carbonization of ZIF-8(Zn)at different temperature,and the microwave absorption performance was *** porous N-doped carbon inherits the high porosity of ZIF-8 *** increasing the carbonization temperature,the contents of Zn and N elements are decreased;the graphitization degree is improved;however,the specific surface area and porosity are increased first and then *** the carbonization temperature is 1000°C,the porous N-doped carbon behaves enhanced microwave *** an ultrathin thickness of 1.29 mm,the ideal RL reaches-50.57 dB at 16.95 GHz and the effective absorption bandwidth is 4.17 *** mechanism of boosted microwave absorption is ascribed to the competition of graphitization and porosity as well as N dopants,resulting in high dielectric loss capacity and good impedance *** porous structure can prolong the pathways and raise the contact opportunity between microwaves and porous carbon,causing multiple scattering,interface polarization,and improved impedance ***,the N dopants can induce electron polarization and defect *** results give a new insight to construct lightweight carbon-based microwave absorbents by regulating the graphitization and porosity.

关键词： N-doped carbon porosity dielectric impedance matching microwave absorption

Zn/O ratio and oxygen chemical state ofnanocrystalline ZnO films grown atdifferent temperatures

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Chinese Physics B 2012年第3期21卷 475-479页

作者：范海波郑新亮吴思诚刘志刚姚合宝 Department of Physics National Key Laboratory of Photoelectric Technology and Functional Materials(Culture Base)National Photoelectric Technology and Functional Materials & Application of Science and Technology International Cooperation BaseNorthwest University

ZnO nanocrystalline films are prepared on Si substrates at different temperatures by using metal-organic chemical vapour deposition （MOCVD）. It is observed that when the growth temperature is low, the stoichiometric ratio between Zn and 0 atoms has a large deviation from the ideal ratio of 1：1. The ZnO grains in the film have small sizes and are not well crystallized, resulting in a poor photoluminescence （PL） property. When the temperature is increased to an appropriate value, the Zn/O ratio becomes optimized, and most of Zn and 0 atoms are combined into Zn-O bonds. Then the film has good crystal quality and good PL property. If the temperature is fairly high, the interracial mutual diffusion of atoms between the substrate and the epitaxial film appears, and the desorption process of the oxygen atoms is enhanced. However, it has no effect on the film property. The film still has the best crystal quality and PL property.

关键词： ZnO film metal-organic chemical vapour deposition growth temperature Zn/O ratio

Pairing Mismatched ssDNA to dsDNA Studied with Reflectometric Interference Spectroscopy Sensor

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Chinese Physics Letters 2016年第8期33卷 151-154页

作者：武青青王凯歌孙聃王爽张琛赵伟 Institute of Photonics & Photon-Technology National Center for International Research of Photoelectric Technology &Nano-functional MaterialsState Key Laboratory of Cultivation Base for Photoelectric Technology and Functional MaterialsKey Laboratory of Optoelectronic Technology of Shaanxi ProvinceNorthwest University

The interaction between two single-stranded DNA （ssDNA） molecules as pairing to a double-stranded DNA （dsDNA） molecule is studied by the reflectometric interference spectroscopy （RIFS） technology. A nano-porous anode alumina membrane coated an Au layer is employed as the sensor substrate. The results indicate that when there are mismatched nucleotide bases, the effective optical thicknesses （OTeft） have obvious difference, and the changes of OTeff are connected with the sensor layer thickness and the effective refractive index. It is also demonstrated that the RIFS technique can be used to precisely detect the ssDNA molecules with individual base mismatched as pairing to dsDNA.

关键词： dsDNA is will ssDNA of with

Microstructure and Thermal-protective Property of CPED Coating with ZrO2 Nanoparticles Addition on Al-12Si Alloy

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Journal of Wuhan University of Technology(materials Science) 2019年第5期34卷 1187-1192页

作者： WANG Ping MA Qun LI Bin LI Yaoyao Shaanxi key laboratory of photoelectric functional materials and Devices School of Materials and Chemical Engineering Xi’an Technological University

A novel thermal-protective coating has been successfully prepared by CPED process on a cast Al-12%Si alloy with the addition of ZrO2 nano-particles in the electrolyte. The microstructures and phase composition of the coatings were analyzed by SEM and XRD, and the heat insulation performance and the thermal shock resistance of the coatings were investigated. With ZrO2 nanoparticles addition, the cathode plasma discharge on the coating surface is more obvious than that without ZrO2 nanoparticles addition, the coating is more uniform and compact, and the thickness of the coating increases. Furthermore, the content of Zr and Y elements increases and the degree of crystallization of the coating is more complete. The formation of the solid solution of yttrium stabilized zirconia is promoted by cathode plasma discharge. In addition, the thermal insulation temperature increases as ZrO2 nano-particles are added to the electrolyte. After 1 000 cycles of thermal shock, there was no cracking in the coating surface layer, which indicated that the CPED coating with ZrO2 nanoparticles addition possessed a good thermal shock resistance.

关键词： Al-12Si piston alloy cathode plasma electrolytic deposition(CPED) ZrO2 nanoparticles heat-shielding performance thermal shock performance

Hydrogen storage properties of mechanically milled La_2Mg_(17-x)wt.%Ni(x=0,50,100,150 and 200) composites

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Journal of Rare Earths 2013年第7期31卷 694-700页

作者：李霞赵栋梁张羊换许剑轶张国芳张胤 Department of functional Material Research Central Iron and Steel Research Institute inner mongolia key laboratory for Utilization of Bayan Obo Multi-Metallic Resources:Elected State key laboratory Inner Mongolia University of Science and Technology School of Rare Earth Inner Mongolia University of Science and Technology

Melting method was used to obtain La2Mg17 alloy, and then Ni powder was added by mechanical alloying method. The kinetics of hydriding process and electrochemical properties of La2Mg17-X wt.%Ni （x=0, 50, 100, 150, 200） composites were investigated. X-ray diffraction （XRD） and scanning electron microscopy （SEM） analyses showed that the crystal structure of composite alloy gradually transformed into amorphous phase by the effect of ball milling and Ni powders. The research of hydrogen absorption properties found that La2Mg17-50 wt.%Ni reached the highest hydrogen absorption than other alloys with more addition of Ni content, reached to 5.796 wt.% at 3 MPa, and up to 5.229 wt.% merely in 2 min, which revealed that the amorphous phase reduced the H occupation of the lattice clearance, resulting in the decline of hydrogen absorption capacity. The electrochemical tests indicated that the maximum discharge capacity increased to 353.1 mAh/g at 30 ℃, however, the cycle stability decreased considerably./~ series of ki- netic measurements demonstrated that the controlling steps of electrochemical process of La2Mg17-x wt.%Ni alloys transferred from hydrogen diffusion on alloy bulk （x=50, 100） to hydrogen diffusion on both alloy bulk and surface （x=150, 200）.

关键词： hydrogen storage materials ball-milling electrochemical properties amorphous rare earths