scholarly journals Formation of Nanoporous Mixed Aluminum-Iron Oxides by Self-Organized Anodizing of FeAl3 Intermetallic Alloy

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2299 ◽  
Author(s):  
Paulina Chilimoniuk ◽  
Marta Michalska-Domańska ◽  
Tomasz Czujko
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Anodic Oxide ◽  
Oxide Thickness ◽  
Structural Features ◽  
Intermetallic Alloy ◽  
Oxide Mixture ◽  
Oxide Layers ◽  
Voltage Range ◽  
Interpore Distance

Nanostructured anodic oxide layers on an FeAl3 intermetallic alloy were prepared by two-step anodization in 20 wt% H2SO4 at 0 °C. The voltage range was 10.0–22.5 V with a step of 2.5 V. The structural and morphological characterizations of the received anodic oxide layers were performed by field emission scanning electron microscopy (FE-SEM). Therefore, the formed anodic oxide was found to be highly porous with a high surface area, as indicated by the FE-SEM studies. It has been shown that the morphology of fabricated nanoporous oxide layers is strongly affected by the anodization potential. The oxide growth rate first increased slowly (from 0.010 μm/s for 10 V to 0.02 μm/s for 15 V) and then very rapidly (from 0.04 μm/s for 17.5 V up to 0.13 μm/s for 22.5 V). The same trend was observed for the change in the oxide thickness. Moreover, for all investigated anodizing voltages, the structural features of the anodic oxide layers, such as the pore diameter and interpore distance, increased with increasing anodizing potential. The obtained anodic oxide layer was identified as a crystalline FeAl2O4, Fe2O3 and Al2O3 oxide mixture.

scholarly journals Formation of Nanoporous Mixed Aluminum-Iron Oxides by Self-Organized Anodizing of FeAl3 Intermetallic Alloy

2019 ◽  
Author(s):  
Paulina Chilimoniuk ◽  
Marta Michalska-Domańska ◽  
Tomasz Czujko
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Anodic Oxide ◽  
Oxide Thickness ◽  
Structural Features ◽  
Intermetallic Alloy ◽  
Oxide Mixture ◽  
Oxide Layers ◽  
Voltage Range ◽  
Interpore Distance

Nanostructured anodic oxide layers on an FeAl3 intermetallic alloy were prepared by two-step anodization in 20 wt.% H2SO4 at 0°C. The voltage range was 10.0 – 22.5 V with a step of 2.5 V. The structural and morphological characterizations of the received anodic oxide layers were performed by FE-SEM. Therefore, the formed anodic oxide was found to be highly porous with a high surface area, as indicated by the FE-SEM studies. It has been shown that the morphology of fabricated nanoporous oxide layers is strongly affected by the anodization potential. The oxide growth rate first increased slowly (from 0.010 μm/s for 10 V to 0.02 μm/s for 15 V) and then very rapidly (from 0.04 μm/s for 17.5 V up to 0.13 μm/s for 22.5 V). The same trend was observed for the change in the oxide thickness. Moreover, for all investigated anodizing voltages, the structural features of the anodic oxide layers, such as the pore diameter and interpore distance, increase with increasing anodizing potential. The obtained anodic oxide layer was identified as a crystalline FeAl2O4, Fe2O3 and Al2O3 oxide mixture.

Nanofibrous Scaffold Engineering Using Electrospinning

2007 ◽  
Vol 7 (12) ◽  
pp. 4595-4603 ◽  
Author(s):  
R. Murugan ◽  
Z. M. Huang ◽  
F. Yang ◽  
S. Ramakrishna
Keyword(s):  
Tissue Engineering ◽  
Cell Attachment ◽  
Dimensional Space ◽  
High Surface ◽  
Critical Role ◽  
High Surface Area ◽  
Structural Features ◽  
Tissue Growth ◽  
High Porosity ◽  
Fibrous Scaffold

Scaffold plays a critical role in tissue engineering where it provides necessary structural support for the cells to accommodate and to guide their growth in the three dimensional space into a specific tissue. Therefore, engineering scaffolds favorable for cell/tissue growth is of great importance and a pre-requisite for scaffold-based tissue engineering. Electrospinning is a versatile method that has been recently adapted in engineering nano-fibrous scaffolds that mimic the structural features of biological extracellular matrix (ECM). It offers many advantages over conventional scaffold methodologies, for example, capable of producing ultra-fine fibers with high porosity, high spatial orientation, high aspect ratio, and high surface area, which are highly required for the initial cell attachment, tissue formation, and continued function. Considering these astonishing merits, this article emphasis on nano-fibrous scaffold engineering by electrospinning.

Cellulose generated-microporous carbon nanosheets with nitrogen doping

RSC Advances ◽  
2014 ◽  
Vol 4 (18) ◽  
pp. 9126-9132 ◽  
Author(s):  
Wenzhong Shen ◽  
Tuoping Hu ◽  
Weibin Fan
Keyword(s):  
Surface Area ◽  
Porous Carbon ◽  
Pore Volume ◽  
Nitrogen Doping ◽  
High Surface ◽  
High Surface Area ◽  
Structural Features ◽  
Carbon Nanosheets ◽  
Nitrogen Doped ◽  
Adsorption Performance

Nanosheet porous carbon with high surface area and pore volume, unique compositional and structural features endow the nitrogen-doped porous carbon nanosheets with superior CO2 adsorption performance.

Formation and Characterization of Oxides on GaN surfaces

2000 ◽  
Vol 622 ◽  
Author(s):  
D. Mistele ◽  
T. Rotter ◽  
F. Fedler ◽  
H. Klausing ◽  
O.K. Semchinova ◽  
...  
Keyword(s):  
Saturated Calomel Electrode ◽  
Depth Profiling ◽  
Amorphous State ◽  
Theoretical Work ◽  
Oxide Thickness ◽  
X Ray Diffraction ◽  
Oxide Layers ◽  
Voltage Range ◽  
Polar Surfaces

ABSTRACTWe characterized oxides formed directly on n-GaN surfaces. The methods used for oxide layer formation were both photoanodic oxidation and thermal oxidation. The photoanodic oxidation took place in aqueous solutions of potassium hydroxide with pH values lower than 13. Homogenous oxide films were obtained in the voltage range from -0.6 V to 0.4 V vs the saturated calomel electrode (SCE). The characterization of the oxide layers was performed primarily by Auger electron spectroscopy (AES). First the surface chemistry was determined, proving that Ga-oxide is formed with an attributed stoichiometry of Ga2O3. Secondly, depth profiling shows the oxide thickness to be dependent on the photoanodic voltage and oxidation time. Complementary X-ray diffraction (XRD) studies suggest an amorphous state of the formed layers. Annealing GaN in O2-atmospheres above 900°C also lead to surfaces fully covered with gallium oxide. We found that N-polar surfaces oxidize faster than Ga-polar surfaces, which is in agreement to the theoretical work of Zywietz et al [1]. Furthermore, we report on the electrical properties of the anodized oxide layers by analyzing MOS structures.

scholarly journals Multifunctional and Environmentally Friendly TiO2–SiO2 Mesoporous Materials for Sustainable Green Buildings

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4226
Author(s):  
Ghedini ◽  
Menegazzo ◽  
Manzoli ◽  
Di Michele ◽  
Puglia ◽  
...  
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Environmentally Friendly ◽  
Green Building ◽  
Structural Features ◽  
Modulated Dsc ◽  
Synthetic Approach ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method

This work deals with the formulation of environmentally friendly, cheap, and readily-available materials for green building applications, providing the function of air purificator by improving the safety and the comfort of an indoor environment. High surface area TiO2–SiO2 samples, prepared by a simple, cost effective, and scalable synthetic approach, proved to be effective in maximizing the properties of each component, i.e., the photocatalytic properties of titania and the high surface area of silica. TiO2 was introduced onto an ordered mesoporous silica Santa Barbara Amorphous-15 (SBA-15), that is featured by interesting insulating features, by using an incipient wetness impregnation method. The photocatalytic activity was evaluated in gas phase oxidation of ethylbenzene, which was selected as model volatile organic compound (VOC) molecule. The morphological, textural and structural features along with the electronic properties, the hydrophilicity and heat capacity of the materials were investigated in depth by scanning electron microscopy, powder X-ray diffraction, N2 physisorption, diffuse reflectance UV-Vis, FT-IR spectroscopies, and modulated DSC (MDSC) dynamic scan. Outstanding performances in the ethylbenzene abatement results are promising for further application in the green building sector.

scholarly journals Recent Trends in Morphology-Controlled Synthesis and Application of Mesoporous Silica Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2122
Author(s):  
Nabanita Pal ◽  
Jun-Hyeok Lee ◽  
Eun-Bum Cho
Keyword(s):  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Mesoporous Silica Nanoparticles ◽  
High Surface ◽  
High Surface Area ◽  
Porous Silica ◽  
The United States ◽  
Structural Features ◽  
Energy Applications ◽  
Silica Materials

The outstanding journey towards the investigation of mesoporous materials commences with the discovery of high surface area porous silica materials, named MCM-41 (Mobil Composition of Matter-41) according to the inventors’ name Mobile scientists in the United States. Based on a self-assembled supramolecular templating mechanism, the synthesis of mesoporous silica has extended to wide varieties of silica categories along with versatile applications of all these types in many fields. These silica families have some extraordinary structural features, like highly tunable nanoscale sized pore diameter, good Brunauer–Emmett–Teller (BET) surface areas, good flexibility to accommodate different organic and inorganic functional groups, metals etc., onto their surface. As a consequence, thousands of scientists and researchers throughout the world have reported numerous silica materials in the form of published articles, communication, reviews, etc. Beside this, attention is also given to the morphology-oriented synthesis of silica nanoparticles and their significant effects on the emerging fields of study like catalysis, energy applications, sensing, environmental, and biomedical research. This review highlights a consolidated overview of those morphology-based mesoporous silica particles, emphasizing their syntheses and potential role in many promising fields of research.

scholarly journals Improving Photoelectrochemical Properties of Anodic WO3 Layers by Optimizing Electrosynthesis Conditions

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2916 ◽  
Author(s):  
Marta Zych ◽  
Karolina Syrek ◽  
Leszek Zaraska ◽  
Grzegorz D. Sulka
Keyword(s):  
Surface Morphology ◽  
Tungsten Oxide ◽  
Active Surface ◽  
Anodic Oxide ◽  
Oxide Thickness ◽  
Band Gap Energy ◽  
Electrolyte Composition ◽  
Active Surface Area ◽  
Photoelectrochemical Properties ◽  
Oxide Layers

Although anodic tungsten oxide has attracted increasing attention in recent years, there is still a lack of detailed studies on the photoelectrochemical (PEC) properties of such kind of materials grown in different electrolytes under various sets of conditions. In addition, the morphology of photoanode is not a single factor responsible for its PEC performance. Therefore, the attempt was to correlate different anodizing conditions (especially electrolyte composition) with the surface morphology, oxide thickness, semiconducting, and photoelectrochemical properties of anodized oxide layers. As expected, the surface morphology of WO3 depends strongly on anodizing conditions. Annealing of as-synthesized tungsten oxide layers at 500 °C for 2 h leads to obtaining a monoclinic WO3 phase in all cases. From the Mott-Schottky analysis, it has been confirmed that all as prepared anodic oxide samples are n-type semiconductors. Band gap energy values estimated from incident photon−to−current efficiency (IPCE) measurements neither differ significantly for as−synthesized WO3 layers nor depend on anodizing conditions such as electrolyte composition, time and applied potential. Although the estimated band gaps are similar, photoelectrochemical properties are different because of many different reasons, including the layer morphology (homogeneity, porosity, pore size, active surface area), oxide layer thickness, and semiconducting properties of the material, which depend on the electrolyte composition used for anodization.

scholarly journals VN Quantum Dots Anchored Uniformly onto Nitrogen-Doped Graphene as Efficient Electrocatalysts for Oxygen Reduction Reaction

NANO ◽  
2018 ◽  
Vol 13 (04) ◽  
pp. 1850041 ◽  
Author(s):  
Jing Wang ◽  
Lan Wang ◽  
Shubin Yang
Keyword(s):  
Quantum Dots ◽  
Active Sites ◽  
High Surface ◽  
High Surface Area ◽  
Structural Features ◽  
Vanadium Nitride ◽  
Transport Pathways ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene

A new type of vanadium nitride quantum dots anchored homogeneously onto nitrogen-doped graphene (VNQD-NG) is fabricated as nonprecious metal-based electrocatalysts for ORR via a combined hydrothermal and ammonia annealing process. The unique structural features of VNQD-NG including plentiful VN quantum dots with the sizes of 3–6[Formula: see text]nm, high surface area and multi-level pores afford considerable structural edges and defects as active sites, maximizing the exposed active sites and providing sufficient electron transport pathways for ORR. Hence, the optimized VNQD-NG exhibits high electrocatalytic activity, long durability and high selectivity for ORR, better than commercially available Pt-C.

scholarly journals The Use of Anodic Oxides in Practical and Sustainable Devices for Energy Conversion and Storage

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 383
Author(s):  
Janaina Soares Santos ◽  
Patrícia dos Santos Araújo ◽  
Yasmin Bastos Pissolitto ◽  
Paula Prenholatto Lopes ◽  
Anna Paulla Simon ◽  
...  
Keyword(s):  
Energy Conversion ◽  
High Surface ◽  
High Surface Area ◽  
Dye Sensitized Solar Cells ◽  
Anodic Oxide ◽  
Development Stage ◽  
Anodic Films ◽  
Practical Applications ◽  
Energy Conversion And Storage ◽  
And Storage

This review addresses the main contributions of anodic oxide films synthesized and designed to overcome the current limitations of practical applications in energy conversion and storage devices. We present some strategies adopted to improve the efficiency, stability, and overall performance of these sustainable technologies operating via photo, photoelectrochemical, and electrochemical processes. The facile and scalable synthesis with strict control of the properties combined with the low-cost, high surface area, chemical stability, and unidirectional orientation of these nanostructures make the anodized oxides attractive for these applications. Assuming different functionalities, TiO2-NT is the widely explored anodic oxide in dye-sensitized solar cells, PEC water-splitting systems, fuel cells, supercapacitors, and batteries. However, other nanostructured anodic films based on WO3, CuxO, ZnO, NiO, SnO, Fe2O3, ZrO2, Nb2O5, and Ta2O5 are also explored and act as the respective active layers in several devices. The use of AAO as a structural material to guide the synthesis is also reported. Although in the development stage, the proof-of-concept of these devices demonstrates the feasibility of using the anodic oxide as a component and opens up new perspectives for the industrial and commercial utilization of these technologies.

Hydrothermal and Thermal Decomposition Synthesis of Hierarchical NiO Microspheres with Mesoporous Structure

2011 ◽  
Vol 239-242 ◽  
pp. 252-258
Author(s):  
Hui Liu ◽  
Guang Jun Li ◽  
Jun Qi Li ◽  
Na Wei ◽  
Zhen Feng Zhu
Keyword(s):  
Thermal Decomposition ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Mesoporous Structure ◽  
Structural Features ◽  
Mesoporous Alumina ◽  
N2 Adsorption ◽  
Adsorption Desorption ◽  
Adsorptive Properties

A facile method has been developed to synthesis hierarchical nickel oxide with spherical particle morphologies, high surface area of 234 m2/g and narrow pore distribution at 3.25 nm by controlled thermal decomposition of the nickel nitrate hydroxide precursors. The as-obtained products were well characterized by XRD, SEM, TEM (HRTEM), SAED, FTIR and N2 adsorption-desorption measurement. It was shown that the hierarchical NiO microsphere with the diameter about 2.0 μm is composed of hexagonal nanoparticles with mesoporous structure. The prepared mesoporous materials were used as an adsorbent to remove the Congo red pollutant contained in the waste water, and they exhibited more favorable adsorptive properties than the mesoporous alumina powders with same surface area due to its special structural features.

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