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Full-Text Articles in Nanoscience and Nanotechnology

The Hydrothermal Synthesis Of Nanoscale Lifepo_4 And Its Electrochemical Performance, Si-Min Wang, Ming-Sen Zheng, Quan-Feng Dong Nov 2008

The Hydrothermal Synthesis Of Nanoscale Lifepo_4 And Its Electrochemical Performance, Si-Min Wang, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

The cathode materials of nanosiged LiFePO4 were prepared by hydrothermal templating synthesis.The grain sizes and electrochemical performance of LiFePO4 were controlled by surfactant.It was shown that the grain sizes varied from less than a hundred to hundreds nanometers by the SEM images.In the charge/discharge tests,the discharge capacities of the sample as a lithium ion battery were achieved to 150 mAh/g at 0.1C,140 mAh/g at 1C,and 126 mAh/g at 2C,with good cycling performance.


Nanoporous Materials With Enhanced Hydrophilicity And High Water Capacity, Eng-Poh Ng, Svetlana Mintova Sep 2008

Nanoporous Materials With Enhanced Hydrophilicity And High Water Capacity, Eng-Poh Ng, Svetlana Mintova

Eng-Poh Ng

The main types of nanoporous adsorbents for water are identified and described with emphasis on the mechanism of adsorption, modification, improvement of the water sorption capacity, possible regeneration, and stabilization. Among the three main groups of water sorbents, i.e. inorganic materials (zeolites, clays, silica), carbon based materials and organic polymers, the first one is described in details. The significance of their porosity, chemical and structural features relative to the water adsorptive properties of each inorganic type materials is reviewed. Important features for silicates, zeolites, aluminophosphates, mesoporous materials and clays are described, which define the interactions between the water and the …


Design And Fabrication Of The High Efficient Platinum-Nanoporous Gold Catalysts, Zhao-Na Liu, Jin-Tao Zhang, Fang Tian, Peng-Peng Liu, Hou-Yi Ma, Yi Ding Aug 2008

Design And Fabrication Of The High Efficient Platinum-Nanoporous Gold Catalysts, Zhao-Na Liu, Jin-Tao Zhang, Fang Tian, Peng-Peng Liu, Hou-Yi Ma, Yi Ding

Journal of Electrochemistry

The nanoporous gold(NPG) electrodes with uniform pore sizes and ligaments were prepared by using a simple dealloying method.The as-prepared NPG showed high catalytic activity towards the oxidation of formic acid and formaldehyde.After tiny amount of platinum was deposited onto the NPG substrate,not only the structure stability of NPG was greatly improved,but also the Pt-Au bimetallic catalysts displayed the better catalytic activity and the stronger poison resistance towards the electrooxidation of small organic molecules than the bulk platinum due to synergistic effect between Au and Pt compositions.


Study On Electrocatalytic Oxidation Of Salbutamol At Carbon Nanotubes Modified Electrode, Ying-Liang Wei, Lu-Ping Zhang, Chen Shao, Hui Feng, Xian-Li Li Aug 2008

Study On Electrocatalytic Oxidation Of Salbutamol At Carbon Nanotubes Modified Electrode, Ying-Liang Wei, Lu-Ping Zhang, Chen Shao, Hui Feng, Xian-Li Li

Journal of Electrochemistry

The multi-wall carbon nanotubes(MWNT) were dispersed successfully into water in the presence of dihexadecyl hydrogen phosphate(DHP) and a stable well-distributed suspension.A was formed sensor based on the multi-carbon nanotubes film coated glassy carbon electrode was developed.The electrochemical response of salbutamol was studied by square wave voltammetry.The oxidation peak potential of salbutamol at the modified electrode was observed at 0.604 V,which shifted about 40 mV negatively.The peak current increased 4.5 folds,in contrast to that at a bare electrode.Under optimal measurement conditions,there was a good linear relationship between the peak current(Ipa) and salbutamol concentration(C) in the range from 8.3 × 1 0-7~ …


Electrochemical Synthesis,Characterization And Fluorescence Property Of Nano Na_2sif_6, Guo-Xu Qin, Xin-Jun Wan, Xi-Mei Yuan, Dao-Bao Chu Aug 2008

Electrochemical Synthesis,Characterization And Fluorescence Property Of Nano Na_2sif_6, Guo-Xu Qin, Xin-Jun Wan, Xi-Mei Yuan, Dao-Bao Chu

Journal of Electrochemistry

The nano TiO2 film was prepared by sol-gel process and characterized with X-ray diffraction(XRD) and scanning electron microscope(SEM).It was found that the average size of pore diameter was about 80 nm for the nano TiO2 film.The Nano Na2SiF6 was synthesized by electrochemical deposition on the nanoporous film electrode and characterized with XRD and transmission electron microscope(TEM).The result showed that the average size of nanoparticle was 20 nm for the nano Na2SiF6.The fluorescence property of nano Na2SiF6 was also studied briefly.The result indicated that the nano Na2SiF6 exhibited strong fluorescence emission at 452.4 nm and 285 nm,respectively.


Electrocatalytic Oxidation Of Salicylic Acid At Novel Gold Nanoparticle-Modified Glassy Carbon Electrode, Yan-Ping Cui, Chang-Zhu Yang, Jian Huang, Wen-Hong Pu, Jing-Dong Zhang Aug 2008

Electrocatalytic Oxidation Of Salicylic Acid At Novel Gold Nanoparticle-Modified Glassy Carbon Electrode, Yan-Ping Cui, Chang-Zhu Yang, Jian Huang, Wen-Hong Pu, Jing-Dong Zhang

Journal of Electrochemistry

A gold nano-particles modified glassy carbon electrode(GNP/GCE) was prepared by the"seed-mediated gold nano-particles growth method".Field emission scanning electron microscopy,ultraviolet-visible(UV-vis) spectroscopy analysis and electroalaylsis were employed to study the morphology and electrochemical performances.The resulting electrode showed excellent electro-catalytic activity toward the oxidation of salicylic acid and the response sensitivity was 1.8 fold than that obtained on GCE.Good linear relationship was obtained between response current and salicylic acid concentration in the range of 5.0 × 10-7 ~8.0 × 10-5 mol/L,which could be used in the detection of trace salicylic acid.


Estimating Local Greenhouse Gas Emissions - A Case Study On A Portuguese Municipality, João F. Gomes Jan 2008

Estimating Local Greenhouse Gas Emissions - A Case Study On A Portuguese Municipality, João F. Gomes

João F Gomes

This paper describes the study that led to the development of a carbon dioxide emissions matrix for the Oeiras municipality, one of the largest Portuguese municipalities, located in the metropolitan area of Lisbon. This matrix takes into account the Greenhouse Gases (GHG) Emissions, due an increase of electricity demand in buildings as well as solid and liquid wastes treatment, from the domestic and services sectors. Using emission factors that were calculated from the relationship between the electricity produced and amount of treated wastes, the GHG emissions in the Oeiras municipality, were estimated for a time series of 6 years (1998 …


Dynamic Simulation Of Co2 Absorption From Post Combustion Gases, João Gomes Jan 2008

Dynamic Simulation Of Co2 Absorption From Post Combustion Gases, João Gomes

João F Gomes

CO2 capture from combustion flue gases is currently an issue of main interest due to the high taxes being imposed on industrial companies as a measure to achieve CO2 emissions abatement. CO2 capture can be efficiently achieved by gas absorption using amines, namely Monoethanolamine (MEA). Based on henrys law, validated with previously published experimental work, this study considers the development of a dynamic model of an absorption column for post combustion CO2 capture. A dynamic model of the temperature swing de-absorption process was developed with the integration of both models for absorption and de-absorption (with the introduction of heat exchangers, …


Reflexions On The Use Of Renewable Power Sources And Nuclear Energy In Portugal, João F. Gomes Jan 2008

Reflexions On The Use Of Renewable Power Sources And Nuclear Energy In Portugal, João F. Gomes

João F Gomes

This paper analyses the current energy balance of Portugal, considering the actual sources which are mainly traditional fossil fuels, hydroelectric power and renewables. Other potential sources are discussed also and taken into consideration in view of the previewed evolution of the country in energetic terms. Among these, nuclear power, once regarded as an option, is now being re-considered. This paper also sums up the main issues to be considered in a future debate on the subject.


Alpo-18 Seed Layers And Films By Secondary Growth, Lubomira Tosheva, Eng-Poh Ng, Svetlana Mintova, Manfred Holzl, Till H. Metzger, Aidan M. Doyle Jan 2008

Alpo-18 Seed Layers And Films By Secondary Growth, Lubomira Tosheva, Eng-Poh Ng, Svetlana Mintova, Manfred Holzl, Till H. Metzger, Aidan M. Doyle

Eng-Poh Ng

AlPO-18 layers were prepared on Si wafers via spin-coating or the Langmuir−Blodgett (LB) method using nanosized crystals. Multilayers were deposited by spin-coating, whereas the seeds assembled by the LB technique were monolayers. The seeded layers were not stable upon secondary growth under microwave radiation, and no films were formed on the supports. Dense AlPO-18 films could be obtained by secondary growth after stabilization of the seed layers by adding prehydrolyzed tetraethylorthosilicate (TEOS) to the colloidal AlPO-18 suspension prior to support seeding. The stabilized seed layers and the grown AlPO-18 films were stable. The structure and the morphology of the films …


Environmentally Benign Synthesis Of Nanosized Aluminophosphate Enhanced By Microwave Heating, Eng-Poh Ng, Luc Delmotte, Svetlana Mintova Dec 2007

Environmentally Benign Synthesis Of Nanosized Aluminophosphate Enhanced By Microwave Heating, Eng-Poh Ng, Luc Delmotte, Svetlana Mintova

Eng-Poh Ng

The problem addressed with our paper is on the efficient utilization of reacting materials for enhanced syntheses of nanosized aluminophosphate molecular sieve by microwave heating, and decreasing or almost eliminating the related waste. The synthesis procedure deals with the environmental issues concerning the future manufacture re-use and disposal of non-reacted chemicals associated with the production of nanosized aluminophosphate. Nanosized AlPO-18 has been prepared by a multicycle synthesis approach via re-using non-reacted compounds from precursor suspensions with minimal requirement of chemical compensation after recovering of crystalline nanoparticles from each step. This approach is implied as environmentally benign and results in almost …


Emissions Of Polyciclic Aromatic Hidrocarbons And Polyciclic Carbonyl Bifenils From Electric Arc Furnaces, João F. Gomes Dec 2007

Emissions Of Polyciclic Aromatic Hidrocarbons And Polyciclic Carbonyl Bifenils From Electric Arc Furnaces, João F. Gomes

João F Gomes

This paper describes work done in order to determine the emissions of highly toxic organic micropollutants from electric arc furnaces used in the production of carbon steel from scrap. The study will be allowing to derive relationships between the levels of airborne micropollutants and the operational parameters of the production process so that an abatement of pollution could be achieved. By using the European standard method CEN 1948 for dioxin like compounds sampling and measurement, it was possible to determine the characteristic fingerprint of micropollutants such as polycyclic aromatic hydrocarbons (PAHs) and PCBs emitted by this particular stationary source.