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Beijing Wuzi University is a higher education institution based in the capital of China, Beijing. It is also refer to Beijing Wuzi University. Wikipedia.

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Li Y.,Peking University | Sun Q.,Beijing Materials University
Advanced Energy Materials | Year: 2016

The increasing concentration of CO2 in the atmosphere, and the resulting environmental problems, call for effective ways to convert CO2 into valuable fuels and chemicals for a sustainable carbon cycle. In such a context, CO2 electrocatalytic reduction has been hotly studied due to the merits of ambient operational conditions and easy control of the reaction process by changing the applied potential. Among the various systems studied, Cu and Au are found to possess the highest Faradaic efficiency toward cathodic electrocatalytic conversion of CO2 to hydrocarbons and CO, respectively. However, both of them suffer from large overpotentials owing to the limitations imposed by the scaling relations between the carbonaceous adsorbates. Therefore, establishing how to break the scaling relations for effective electrochemical conversion of CO2 has become an urgent research topic. The recent advances in breaking the adsorption energy scaling relations to reduce the overpotential, improve the catalytic activity and suppress the side reaction, are summarized. The origin of the scaling relations, their negative effects on CO2 electrocatalysis, and the strategies for breaking the limitations are discussed. Some suggestions for future study are also proposed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhao X.,Beijing Materials University | Xia D.,Beijing Materials University | Yue J.,Beijing University of Technology | Liu S.,Beijing University of Technology
Electrochimica Acta | Year: 2014

A novel C/Fe3C composite prepared by simple polymerization- pyrolysis of iron phthalocyanine (PcFe) at 700 C in an Ar atmosphere, exhibits a high reversible capacity, stable cyclability, excellent rate performance, improved initial efficiency and reduced hysteresis as an anode material for lithium ion batteries. In-situ embedded Fe3C nanoparticles and N doping can enhance electrical conductivity and facilitate the reaction of C/Fe3C electrode effectively. This work provides a new way for developing high performance non-graphitic carbon electrode materials in the future.© 2013 Published by Elsevier Ltd. All rights reserved.

Qiu B.,Beijing University of Technology | Zhao X.,Beijing University of Technology | Xia D.,Beijing University of Technology | Xia D.,Beijing Materials University
Journal of Alloys and Compounds | Year: 2013

This study reports a novel strategy of preparing CoS2/reduced graphene oxides (RGO) nanocomposites by employing graphene oxides (GO) as an oxidizing agent and Na2S2O3 as a reducing agent. CoS2 can be in situ synthesized with GO being reduced. X-ray diffraction (XRD), Raman spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical test are used to characterize the nanocomposite. The CoS2 particles with the size of 150 nm are dispersed in the networks made from thin RGO nanosheets. The CoS 2/RGO nanocomposite as an anode material for lithium-ion batteries can deliver excellent reversible capacity retention (640 mA hg-1) after cycling 50 times when tested at 100 mA g-1 and rate performance. The enhanced electrochemical properties can be attributed to the nanoscale particles sizes of CoS2 in addition to the effects of RGO networks in preventing the agglomeration of CoS2 and absorbing lithium polysulfides during the charge-discharge processes. © 2013 Elsevier B.V. All rights reserved.

Su S.,Beijing Materials University | Ma H.,Beijing Materials University
Advanced Materials Research | Year: 2012

Zeolite A was successfully synthesized via convenient hydrothermal process using potassium-extracted residue of potassium feldspar as a combined source for silica and alumina. Optimization studies on the molar ratios of Na 2O/SiO 2 and H 2O/SiO 2, and aging time have been conducted. The results were that pure zeolite A with high crystallinity could be synthesized when the reaction mixture with molar ratios of Na 2O/SiO 2 and H 2O/SiO 2 of 2.0 and of 85, respectively, were crystallized at 100°C for 3h. Aging was found to be not prerequisite for the formation of zeolite A in the system. The product was characterized by XRD, FTIR, SEM and calcium exchange capacity. Finally, a comparative study of the zeolite A formation from the potassium-extracted residue and other industrial waste or natural silicate minerals was also carried out. © (2012) Trans Tech Publications, Switzerland.

Zhu Z.,Beijing Materials University | Zhang D.,Taiyuan University of Technology | Yan H.,Beijing Materials University | Li W.,University of Science and Technology Beijing | Qilu,Beijing Materials University
Journal of Materials Chemistry A | Year: 2013

This work developed a novel ammonium oxalate-carbonate composite co-precipitation method to prepare spinel LiNi0.5Mn 1.5O4. By this method combined with a facile hydrothermal treatment and particular cooling process, an ideal spinel with precise stoichiometric Ni/Mn and classic Fd3m structure is obtained, and furthermore, the Mn3+ content can be strictly limited. Additionally, the prepared LiNi0.5Mn1.5O4 has a spherical hierarchical morphology, composed of nano or submicron primary particles. This LiNi 0.5Mn1.5O4 shows superlative electrochemical performance. It delivers a discharge capacity of 141.2 mA h g-1, and importantly 98.2% of which discharges at 4.7 V. After 200 cycles at 0.3 C, 1 C and 3 C, the capacity retentions are 96.3%, 94.4% and 91.1%, respectively. Chemical and electrochemical measurements indicate that the elimination of the majority of Mn3+ in the obtained LiNi0.5Mn 1.5O4 results in the high capacity proportion at 4.7 V. Additionally, the retained Fd3m structure and spherical hierarchical morphology also effectively favour the cycling and rate performances. This journal is © 2013 The Royal Society of Chemistry.

Xie J.,Beijing Natural Science Foundation Commission Office | Xia D.-G.,Beijing Materials University
Fuel Cells | Year: 2013

Pt29Ru51P15 particles with a uniform size distribution of 2 nm supported on multi-walled carbon nanotubes (CNTs) have been prepared with the assistance of thioglycolic acid functionalization using NaH2PO2 · H2O as a reducing agent. The Pt29Ru51P15/CNTs has been characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Its electrochemical properties have been examined by cyclic voltammetry (CV) and chronoamperometry (CA). The results show that Pt29Ru51P15/CNTs has a much narrower particle size distribution with no formation of aggregates, a greater electrochemically active surface area, and higher electrocatalytic activity for the electro-oxidation of methanol Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhou J.,Beijing Materials University | Wang Q.,Virginia Commonwealth University | Sun Q.,Beijing Materials University | Sun Q.,Virginia Commonwealth University | Jena P.,Virginia Commonwealth University
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

First-principles calculations based on density-functional theory reveal some unusual properties of BN sheet functionalized with hydrogen and fluorine. These properties differ from those of similarly functionalized graphene even though both share the same honeycomb structure. (1) Unlike graphene which undergoes a metal to insulator transition when fully hydrogenated, the band gap of the BN sheet significantly narrows when fully saturated with hydrogen. Furthermore, the band gap of the BN sheet can be tuned from 4.7 to 0.6 eV and the system can be a direct or an indirect semiconductor or even a half-metal depending on surface coverage. (2) Unlike graphene, the hydrogenation of BN sheet is endothermic. (3) Unlike graphene, BN sheet has heteroatomic composition. When codecorated with H and F, it can lead to anisotropic structures with rich electronic and magnetic properties. (4) Unlike graphene, BN sheets can be made ferromagnetic, antiferromagnetic, or magnetically degenerate depending on how the surface is functionalized. (5) The stability of magnetic coupling of functionalized BN sheet can be further modulated by applying external strain. Our study highlights the potential of functionalized BN sheets for unusual applications. © 2010 The American Physical Society.

Zhu Z.,Beijing Materials University | Yan H.,Beijing Materials University | Zhang D.,Taiyuan University of Technology | Li W.,University of Science and Technology Beijing | Lu Q.,Beijing Materials University
Journal of Power Sources | Year: 2013

LiNi0.5Mn1.5O4 as a 4.7 V cathode material is prepared through an oxalic acid-pretreated solid-state method. Oxalic acid is added to react with the mixture of LiOH•H2O, MnO2 and Ni(OH)2. This chemical pretreatment results in a sufficient mixing of Li, Ni and Mn ions in the precursor, and therefore promotes the generation of pure LiNi0.5Mn1.5O4 in the following calcination even at a temperature as low as 500 °C. The material prepared at 750 °C has a highest crystallinity and a regular crystal shape with smoothly surface. Compared to traditional method, the LiNi 0.5Mn1.5O4 synthesized by this novel method shows much better electrochemical performances with an initial discharging capacity of 136.9 mAh g-1 and capacity retention of 93.4% after 300 cycles under 0.3C. And most importantly 97.2% of the total capacity displays at 4.7 V, which significantly favors the cell energy density. The novel preparation technique is also available to get high rate performance for LiNi 0.5Mn1.5O4. The material synthesized at 900 °C has a capacity of 121.2 mAh g-1 and stable cycling performance under 3C due to its lower polarization resistance. © 2012 Elsevier B.V. All rights reserved.

Cao X.,Beijing Materials University
Naihuo Cailiao/Refractories | Year: 2013

Two magnesium aluminate spinel specimens were prepared using light-burnt magnesite powder and analytically pure MgO powder as magnesia sources, respectively, industrial α-Al2O3 powder as alumina source, batching with n(MgO): n(Al2O3) =1:1, ball milling, shaping, then firing at 1550 °C, 1600 °C and 1650 °C for 3h, respectively. The densities, strengths, phase compositions and microstructures of the two specimens were compared. The results show that; (1) the densities and strengths of the two specimens increase with synthesis temperature rising; at the same synthesis temperature, the specimen using light-burned magnesite as magnesia source has higher density and strength; (2) for the specimens synthesized at 1650 °C: using light-burnt magnesite as magnesia source, the phases are mainly spinel with a little CA2 and CaSiO3, and the spinel crystals grow well with octahedron morphology; using analytically pure MgO as magnesia source, the main phase is single-phase magnesium aluminate, only a few crystals form completely octahedron morphology; (3) the SiO 2 and CaO in light-burnt magnesite are in favor of the formation of the low melting point phase of CaO-Al2O3-MgO-SiO 2 system promoting the magnesium aluminate spinel crystals growth and specimen sintering.

Zhu Q.,Beijing Materials University
Energy Procedia | Year: 2011

This paper apprises the law of "Plastic-bag ban (PBB)" and points out that the law is necessary, feasible and effective. The success of the PBB policy is represented by the fact that the policy is consistent with the public opinion, and has definite control target. PBB has been properly carried out in supper markets, and has reduced the usage of plastic bags by two thirds. However, the public understanding of PBB needs to be further deepened. The paper analyses the cause of illegal use and wholesaling of ultra-thin plastic bags in peddler' and wholesale markets, and advances some policy suggestions including strengthening the propaganda of PBB and the regulation over peddler's markets and production of plastic bags, increasing the price of plastic bags and establishing relevant law and regulation systems. © 2011 Published by Elsevier Ltd.

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