Essay: Preparation of Vanadium pentoxide Nanostructures and Their Characterization

Abstract
Vanadium oxide based compounds are known to be excellent catalysts in many chemical processes. Over the years they have been developed and modify in order to broaden their application. In particular attempts have been done to prepare vanadium oxide nanostructure with better properties, i.e. higher resistance to corrosion, and containing ions and/or noble transition metals, i.e. palladium, silver, and many others.
The aim of the final year work was the preparation under mild condition of novel vanadium oxide nanostructures containing ammonium ions starting from V2O5. These species are considered potential catalysts with a broad applicability in heterogeneous processes, in particular for organic synthesis like esterification and oxidation.
Novel vanadium oxide based nanostructures were synthesized and characterized by powder
X-ray and Scanning Electron Microscopy.The latter has shown various types of structures: nanodisks, rods and granules, with sizes ranging from hundreds of nanometers up to few micron.
List of tables
Table 1: : IR (V-O) spectral data for ammonium vanadate compounds 17
Table 2: : IR (V-O-V) spectral data for ammonium vanadate compounds 18
List of figures
Fig.1.1 SEM analysis of some nanostructures : (1) nanospheres(2) nanoparticles (3) nanorings (4) nanowires 3
Fig.1.2: Oxidation states of vanadium 1in acidic solution. from left to right the oxidation state goes from +5 to +2. 5
Fig.1 3: Vanadium(V) pentoxide structure. 6
Fig.1.4: Molecular structure of V(v) precursors in the PH range from 2 to 8. 9
Fig.1.5: example of a Cyclic compound [V4O12]-4 9
Fig.3.1: XRD patterns of (a) (NH4)4V6 O17.14H2O prepared by refluxing from the isopropanol ammonium vanadate aqueous solution(sample1) (b) the mixture of NH4V3O8’0.5H2O and V2O5 prepared by precipitation at pH = 2 from ammonium vanadate aqueous solution (sample3), and (c) V2O5 formed by calcinations of the haydrated ammonium vanadate (sample2). (d)there was no basic XRD data at 600 ”C 19
Fig.3. 2: (a) (NH4)4V6O17’14H2O nanodisks prepared by the reflux method (sample 1), (b) V2O5 nanodisks and granules formed by calcinating sample 1 at 400 ”C, (c) ammonium vanadates (both (NH4)4V6O17’14H2O and NH4V3O8’0.5H2O) nanorods prepared from aqueous ammonium vanadate solutions by precipitation method (sample 2 and 3), and (d) V2O5 nanorods and sheets formed by calcinating samples 1 and 3 at 400 ”C. 21
Contents
Declaration iii
Abstract iv
List of tables vi
List of figures vii
1. Introduction 1
1.1 Brief introduction to nanostructure: 1
1.2 Nanostructure in chemistry: 2
1.3 Nanostructure applications: 3
1.4 Introduction to Vanadium chemistry: 5
1.6 Introduction to Sample 1: 8
1.7 Aim and objectives: 11
2. Experemental 12
2.1 Materials: 12
2.2 Instrumantation: 12
2.3 X-ray diffraction: 13
2.4 Scanning electron microscope: 13
2.5 Synthesis of [(NH4)4V6O17.14H2O] S1: 14
2.5.1 Synthesis of vanadate solution S2: 14
2.5.2 Synthesis of ammonium trivanadate: 15
3. Results and Discussion 16
3.1 Synthesis: 16
3.2 Spectroscopic characterization: 16
3.3 X-Ray Diffraction: 18
3.4 Scanning electron microscope: 20
4. Conclusion 22
References 23
CHAPTER ONE
Introduction
1.1 Brief introduction to nanostructure:
A nanostructure is an object of intermediate size between molecular and microscopic (micrometer-sized) structures (1,2)
Various definitions of the dimensionality of nanostructures may be found in the literature. For example according to nanoscience and nanotechnologies report from the Royal Society and the Royal Academy of Engineering nanostructures are divided into 3 classes:
Nanoscale in one dimension: thin films layers and surfaces
Nanoscale in two dimensions: carbon nanotubes, inorganic nanotubes, nanowires, biopolymers
Nanoscale in three dimensions: nanoparticles, fullerenes, dendrimers, quantum dots.
Another classification of nanostructures takes into account also materials without a dimension:
(0-D) Nanoparticles, quantum dots, nanodots;
(1-D) Nanowires, nanorods, nanotubes;
(2-D) Coatings, thin-film-multilayers;
(3-D) Bulk; Powders; Other nanostructures, including fractal structures.
Nanomaterials should have two conditions to fulfilled i.e. at least one of dimensions is nano and some properties of these materials are specific to the nano dimension. Indeed, nanomaterials usually exhibit properties that are different from the bulky equivalent. For instance, optical, magnetic and electrical properties are sensitive to size effects. Furthermore, nanosized particles are equally very efficient in the field of catalysis due to its high ratio of surface to volume. Consequently, numerous processes of nanomaterials synthesis are investigated aiming to control their size, morphology, structure and chemical composition.
1.2 Nanostructure in chemistry:
Nanostructure science and technology is fundamentally changing the way that materials and the structures made from them will be manufactured in the future. The increasing ability to synthesize and assemble nanoscale building blocks with precisely controlled sizes and chemistries into consolidated nanostructures and nanocomposites with unique properties and functionalities likely will lead to revolutionary changes in industry.
A key trend in modern science and technology is the exploitation of phenomena occurring on length scales between 1 and 100 nm. The design and synthesis of new materials is a major focus of research worldwide. Novel chemical principles are being applied to create new nanomaterials with novel sensory, mechanical, biological, electronic and magnetic properties. This nanoscience approach has lead to the emergence of fields such as nanobiology, nanochemistry and nanoelectronics. Magnetic nanostructure are interesting scientific objects with many applications, a key advantage of artificial magnetic nanostrucrure is their ability to surpass the performance of naturally occurring magnetic compounds. Magnetic nanostructures can be produced in a variety of geometries such as nanoparticles, nanowires, nanorings. In addition much progress has recently been made towards tuning the chemistry for a given geometry.
The structures and properties of nanomaterials differ significantly from those of atoms and molecules as well as those of bulk materials, synthesis, structures and variety of other properties and there is a large chemical component in each of these aspects. In addition new chemistry making use of these nanounits is making new progress. Electrochemistry and photochemistry using nanoparticles and nanowires, nanocatalysis are examples of such new chemistry.
1.3 Nanostructure applications:
A number of major scientific and technological advances in the area of consolidated nanostructures have occurred in the past decade, and many more are expected. Such advances, some of which are listed below, have already led to commercial scale-up of some nanostructured materials and also to products incorporating them:
Production of layered nanostructures with control of thickness at the atomic level and the subsequently developed ability to engineer the resisto-magnetic-field response by varying nanoscale architecture to make useful devices for magnetic recording.
Development of processes to net-shape-form nanophase ceramics and ceramic-based composites into finished parts while maintaining ultrafine grain size and nanoscale properties when desired.
Discovery and development of unique nanostructured hard and soft magnetic materials for a variety of applications, including information technology hardware.
Development of nanoscale cemented-carbide, hard materials for improved cutting tool performance with superior wear resistance and fracture toughness.
Development of direct methods for fabricating nanostructured coatings yielding exceptional electrical, chemical, thermal, mechanical, and environmental protection of the coated parts.
Creation of a wide range of nanocomposites, such as nanoparticle- or nanotube-filled polymers, with enhanced or fundamentally new and controllable engineering performance, including significantly increased strength and reduced flammability.
Development of biological templating for the directed growth and patterning of nanostructures for biomedical and electronic applications.
Engineering of scaled-up and economical industrial processes for production of nanopowders and nanostructured bulk materials in the multi-tonnage range.
1.4 Introduction to Vanadium chemistry:
Vanadium takes its name from the Scandinavian goddess Vanadis and was discovered in 1801 by Andr”s Manuel del Rio. It was isolated in 1867 by Henry Roscoe as a silvery-white metal that is somewhat heavier than aluminum but lighter than iron.
Vanadium is an element in group 5 of the periodic table and has electron configuration [Ar]3d34s2 in the ground state.
Vanadium has an unusually large number of stable oxidation states (+2, +3, +4, +5), each characterized by a unique color in solution.
Fig.1.2: Oxidation states of vanadium 1in acidic solution. from left to right the oxidation state goes from +5 to +2.
There are at least 15 different vanadium oxides reported till now, such as VO, V2O3, VO2, V2O5, V6O13 and so on. Vanadium oxides and vanadium oxide based catalyst from a number of different interrelated electronic and structural factors(4). These compounds have partially filled d-orbitals which are responsible for different properties. Among these compounds, the most relevant is the V2O5 due to its ability of acting as catalyst in many chemical processes. At room temperature and 1 atm pressure V2O5 is thermodynamically very stable; the stereochemistry of vanadium ions in V2O5 may be considered to be either distorted trigonal bipyramid (five V-O bond length of 1.58-2.02 ” ), or distorted tetragonal pyramid or distorted octahedron (the sixth V-O bond length of 2.79 ” ). Moreover, vanadium pentoxide melts at 690”C and decomposes at 1750”C.
Fig.1.3: Vanadium(V) pentoxide structure.
V2O5 is the catalyst in the Contact Process, the conversion of elemental sulphur into the sulphuric acid. One of the steps in this process consists of the oxidation of SO2 into SO3, which is accomplished by passing sulphur dioxide and oxygen over a solid vanadium (V) oxide catalyst. The mechanism can be explained considering the fact that vanadium has different accessible oxidation states:
SO2 + V2O5 ‘ SO3 + V2O4
V2O4 + ” O2 ‘ V2O5
In the first step the she sulphur dioxide is oxidized to sulphur trioxide by the vanadium(V) oxide. In the process, the vanadium(V) oxide is reduced to vanadium(IV) oxide, followed by re-oxidation of the vanadium(IV) oxide to V2O5 by the oxygen.
Other relevant reactions catalyzed by V2O5 discovered recently there are:
Esterification of aldehydes
Oxidation of Alcohols to Aldehydes and Ketones under Atmospheric Oxygen
Aerobic Oxidation of Activated Alcohols into Acids or Aldehydes in Ionic Liquids
Aerobic Oxidation of Activated Alcohols into Acids or Aldehydes in Ionic Liquids
Oxidation of Aldehydes to the Corresponding Acids in the Presence of Aqueous H2O2
Enantioselective Epoxidation of Allylic Alcohols by a Chiral Complex of Vanadium
And many others are present in literature.
1.6 Introduction to Sample 1:
A wide range of vanadium oxides has been obtained via the hydrothermal treatment of aqueous vanadium(V) solutions. They exhibit large type of nanostructures, ranging from molecular clusters to 1D and 2D layered compounds. Nanotubes are obtained via self-rolling process, while amazing morphologies such as nanospheres, nanoflowers, nanourchins are formed via self-assembling of nanoparticles(5). Self-rolling:metal forming is the process in which metal stock is passed through one or more pairs of rolls to reduce the thickness and to make the thickness uniform.
Great variety of nanostructures have been discovered, ranging from 1D to 3D(6) and V2O5 has even been chosen as a model system for the description of nanostructured materials. At room temperature Vanadium (V) species depend on vanadium concentration and pH(7). Two basic reactions hydrolysis and condensation occurs when vanadium salt is dissolved in water(8).
Vanadium coordination decrease above PH=6 given tetrahedral anionic precursors [HnVO4](3-n)-.
In the pH range from 6 to 9 difunctional anionic precursors [H2VO4]- lead to condensed metavanadate forming cycles or chains(9,10). Cyclic species such as [V4O12]4-.
Fig.1.4: Molecular structure of V(v) precursors in the PH range from 2 to 8.
Fig.1.5: example of a Cyclic compound [V4O12]-4
Among the various metal oxides, vanadium oxide based nanomaterials have been investigated for long time. Vanadium pentoxide has been the most studied vanadium material(10) due to its great potential in a variety of applications ranging from use as cathode in solid state batteries and supercapacitors(11). In particular, various nanostructures have been largely recognized as highly effective materials for ammonia detection(12). NH4V3O8 is one of the most recent vanadium oxide based materials to have rised a strong interest, mainly due to its promising use as cathode materials for Li-ion batteries(12). Currently, of these materials the most studied one is lithium trivanadate (LiV3O8) which have good structural stability its noted that Li+ in (LiV3O8) usually occupy the octahedral sites in the interlayer, which are immobile. For this reason, other cations with larger ionic radius, such as NH4+ could substitute the Li+ in V3O8- layers to form new electrode materials(13,15).
Large number of nanostructured vanadium oxide have been described during the past few years. They are synthesized via the hydrothermal treatment of aqueous solutions of V(v) precursors. This morphology is usually related to the layered structure of orthorhombic V2O5(16). Therefore 1D and 2D structures such as nanowires, nanofibers, nanoribbons, nanobelts or nanosheets are typically reported in the literature. Heating V2O5 for instance leads to different layered compounds depending on PH(16).
The hydrothermal synthesis of nanostructured vanadium oxides currently leads to 1D materials such as nanotubes, nanorods, nanowires or nanobelts. However one further step could be obtained via the self assembling of these 1D structures into curved strucrures such as spheres, flower-like or nanourchins(16).
1.7 Aim and objectives:
The aims of this study are:
modify the V2O5 structure by thermal hydrolysis;
incorporate in the nanostructure ions, specifically NH4+.
Even slight modification of known nanostructure can have severe effect on the physical and chemical properties. In particular the resistance to corrosion is one of the characteristic that are worth to be enhanced
CHAPTER TWO
2. Experemental
2.1 Materials:
All the three reactions were carried out in fume hood. Solvents were per-dried and distilled before use by standard procedures. All chemicals we received from chemical material store of the department of chemistry at SQU and used as received Generally nonmaterial’s are prepared in acidic media (17,20) but very few studies report their synthesis using basic media (21). Here the synthesis of nanosized vanadium oxides reported by thermal decomposition of ammonium vanadate nanomaterials prepared via refluxing precipitation methods in both basic and acidic media.
2.2 Instrumantation:
X-ray diffraction and scanning electron microscope were done in CARRU center at SQU. Infrared (IR) spectra were recorded in CH2CL2 solutions using Nacl cell, on perkin Elmer FT-IR spectrometer in the range 400-4000 cm-1.
2.3 X-ray diffraction:
X-ray diffraction is a convenient method for determining the mean size of nano crystallites in nano crystalline bulk materials. The first scientist, Paul Scherrer, published his results in a paper that included what became known as the Scherrer equation in 1981(21).
This can be attributed to the fact that ‘crystallite size’ is not synonymous with ‘particle size’, while X-Ray diffraction is sensitive to the crystallite size inside the particles. From the well-known Scherrer formula(22).
2.4 Scanning electron microscope:
The SEM system was utilized in diverse areas in the optoelectronics field. For instance, the
system was utilize in the investigation of the buried ridge laser fabrication by monitoring the postetching surface roughness, detecting contamination, and induce defects along the mesa sidewalls during processing and after regrowth of the confinement layer over the l//m active region. One important factor in the progress of the buried-ridge lasers is the mesa height, orientation and dimension of the narrow Ipim active region. The mesa formation is greatly dependent upon the crystal orientation, that is, in the 110 direction the mesa sidewalls can be anisotropic and the 110 direction they can be isotropic. The scanning electron microscope have been used to monitor the surface roughness of structure and analysis of the etched l^m-wide mesas to determine the height(23), orientation and dimension of the mesa sidewalls. Also, photodetectors in the wavelength range 200-380 nm using high quality GaN, A1N, and AlGaN films are being investigated which requires nanoscale characterization to observe the results after growth(23). The monitoring and investigation of novel nitrogen sources and p-type doping possibilities in these films is of primary importance. Lasers in the 2-5 ]im and 7-9 yxa(23). range are required for the optical monitoring and detection of atmospheric pollutants, low loss fluoride based fibers for long haul communications and for medical applications The results achieved up to now has been made possible by the utilization of SEM system, and by daily communication and frequent detailed discussions between the researchers and students involved into every step of the manufacturing and investigation.
2.5 Synthesis of [(NH4)4V6O17.14H2O] S1:
Nanosized ammonium vanadates ( sample 1, sample 2, sample 3 ) were synthesized from solutions of vanadium pentoxide dissolved in aquoues ammoniu solutions using a few different procedures. Sample 1 was synthesized by refluxing a mixed solution of 187 ml of isopropanol and 35 ml of 4.2 M NH4OH aquoues solution, in which 25 g of V2O5 was dissolved the result was orange solution. The orange solution was refluxed in a glass assembly in a heating mental of 70 ”C for 24 h which gives light green solution . the solution was filtered by vacuum and the product obtained thereof was washed with 30 ml of distilled water, then dried in a Petri dish at 60 ”C for 48 h the final product obtained was dark brown solid.
2.5.1 Synthesis of vanadate solution S2:
Sample 2 was prepared from a 170 ml of a buffer solution containing 3.35 M NH4Cl and 1.73 M NH3 (pH=9), in which 9 g of V2O5 was dissolved (0.30 M ) the solution was dark brown . The resultant solution was stirred for 6 h and then placed in an oven 90 ”C for 5 days for evaporation and crystallization. A dense white solution was obtained.
2.5.2 Synthesis of ammonium trivanadate:
Vanadium(V) standard solutions (0.05 M) was prepared by dissolving, at room temperature, pure V2O5 in a 1M NaOH aqueous solution gives a dark yellow solution.
V2O5+ 6NaOH 2Na3VO4+ 3H2O (1)
The above alkaline aqueous solution, containing the vanadium as sodium orthovanadate (Na3VO4), was neutralized with sulfuric acid up to pH ”7 and mixed with weighed quantity of solid ammonium sulphate equivalents to 0.03 M resulting in dark orange solution. At this pH, decavanadate is the predominant product, forming very soluble salt with various cations. After adding of sulfuric acid up to pH 2, the solution was warmed at about 90 ”C and maintained at this temperature for 5 days . In the presence of cations, such as NH4+, that stabilize trivanadate structure, ammonium trivanadate crystallize as typically two-dimensional layered structure (24) , presumably according to the reaction:
3H3V10O283- + 10NH4+ ‘ 10NH4V3O8’+ 4H2O+ H+ (2)
The precipitated phase was filtered from the liquid, washed with 15 ml distilled water and dried at 60 ”C for 48 h the product was purple colored precipitate.
CHAPTER THREE
3. Results and Discussion
3.1 Synthesis:
The vanadium nanostructures were synthesized by a sequence of refluxing from the isopropanol ammonium vanadate aqueous solution, precipitation at pH=2 from ammonium vanadate aqueous solution and by calcinations of the hydrated ammonium vanadate. The products were dried by tube furnace at temperature above 300 ”C and at room temperature. All the products are stable toward light and air at room temperature and were characterized by IR, powder X-ray and scanning electron microscopy.
3.2 Spectroscopic characterization:
The IR of ammonium vanadate [(NH4)4V6O17’ 14H2O] (sample1) , vanadate solution and (NH4V3O8’0.5H2O) (sample3) nanomaterials prepared by the reflux method (sample1) or evaporation and crystallization from ammonium buffer pH=9 vanadate solution (sample2) or by precipitation at pH=2 from ammonium vanadate aqueous solution (sample3) are summarized in Table 1 and Table 2 In the case of hydrated ammonium vanadate , the peak at 973 cm’1 is assigned to the V-O stretching motion of distorted tetrahedral. A broad band at around 640 cm’1 is assumed to be the V-O-V stretching mode, and bands below 400 cm’1 are from the bending modes of V-O and the lattice modes due to literature values, but the Raman spectrophotometer device was not available for use during the preparation of this project to measure the spectra below 640 cm’1 thus, achievement of the last will be in the near future. According to the reported spectra of vanadium oxides and ammonium vanadates, the bands for V-O and V-O-V stretching modes are observed in the frequency ranges of 800-1000 cm’1 and 400-800 cm’1, respectively, while those for the V-O bending and the lattice modes are located below 400 cm’1(28-30) the peak at 986 cm-1 is assigned to the V-O stretching band of distorted square pyramids, while those in the leturature at 709, 535, and 489 cm-1 are due to the V-O-V stretching modes. There is two V-O stretching peak at 973 cm’1 and 871 cm’1 of distorted tetrahedral in V2O5, compared to three V-O stretching peaks for tetrahedral and square pyramids in (NH4)4V6O17’14H2O. A spectral shift was expected to observed for the V-O-V stretching mode in V2O5 from 680 cm-1 for (NH4)4V6O17’14H2O to 700 cm’1 a further investigation will be done in future. The expected shift due to not only different environments of vanadium and oxygen in the lattices but also the hydrogen bonding caused by ammonium ions and water molecules.
Table 1 : IR (V-O) spectral data for ammonium vanadate compounds
Sample IR V-O (cm-1)
1 9986 ,869, 919
2 9973, 871
3 9987, 928, 885
3)
Table 2: IR (V-O-V) spectral data for ammonium vanadate compounds
Sample IR V-O-V (cm-1)
1 9811
2 849
3
3.3 X-Ray Diffraction:
The XRD patterns of the ammonium vanadate and vanadium oxide nanomaterials are shown in Figure 3.1 the diffraction peak of sample1 prepared by the refluxing method is indexed to (NH4)4V6O17’14H2O (JCPDS #21- 0041) (Fig. 3.1 a). The sample prepared from the acidic solution at pH = 2 (sample 3) is believed to be the mixture of ammonium vanadate (NH4V3O8’0.5H2O) and V2O5, as all the diffraction peaks can be indexed to those of (NH4V3O8 ‘0.5H2O) (JCPDS # 41-0492) and orthorhombic V2O5 (JCPDS # 001-0359) (Fig.3.1 b). Hydrated ammonium vanadates have two dimensionally layered structures(25,26) Ammonium H-bonds contribute to the linkage between the different sheets, as well as the ionic interaction. Water molecules of hydrated ammonium vanadates and of hydrated vanadium pentoxide are also known to exist between the layers.1-4,16-18 Vanadium in its higher oxidation state is known to exhibit various isopolyvanadates in aqueous solutions at different pH values and concentrations(27) Vanadium would be in the forms of V4O12 4′, V2O7 4′ , V3O9 3′ ,VO4 3- , VO3(OH)2’ and VO2(OH)2 ‘ ions in high pH media depending on the extent of hydrolysis forming aquo, hydroxo, or oxo species. By altering reaction conditions such as changes in pH values or concentrations of ammonium ion in the ammonium vanadate aqueous solution, different amounts of ammonium ions and water molecules are incorporated into the crystalline structures. Both high pH values and high NH4 + concentrations were shown to lead to the formation of (NH4)4V6O17’14H2O in the present study (samples 1 and 2). Acidification of the solution produced a mixture of NH4V3O8’0.5H2O and V2O5 (sample 3). The diffraction peak of the calcinated sample from hydrated ammonium vanadates, i.e., (NH4)4V6O17’14H2O (samples 1: Fig. 3.1 a) and NH4V3O8’0.5H2O-V2O5 mixture (sample 3: Fig.3.1 b), are indexed to the orthorhombic structure of V2O5 (JCPDS # 001- 0359) (Fig.3.3 c) upon calcination of sample 2
which must have resulted from the release of NH3 and H2O vapor. The conversion of hydrated ammonium vanadates to vanadium pentoxide can be characterized by the frame-work rearrangement of coordination of vanadium atoms as a consequence of release of NH3 and H2O.
3.4 Scanning electron microscope:
FESEM images of hydrated ammonium vanadate and vanadium pentoxide prepared by the reflux and the precipitation methods in aqueous media containing ammonium ions are shown in Figure 3.2 in Figures 3.2a are nanodisks of (NH4)4V6O17’14H2O prepared by the reflux and evaporation methods (sample 1), also disk- and granule-shaped V2O5 obtained upon subsequent calcination of the nanodisks shown in Figure 3.2a have
similar shapes with diameters ranging from 100 to 300 nm and thicknesses of about 60 nm. Figure 3.2b shows that nanorods and nanobelts of about 200 nm in width and about 10 ”m in length were obtained from hydrated ammonium vanadates regardless of whether their components are (NH4)4V6O17’14H2O or NH4V3O8’0.5H2O when they were prepared by evaporation and crystallization or precipitation from the aqueous ammonium solutions. In other words, samples 2 and 3 were obtained with the morphology shown in Figure 3.2c. When samples 1 and 3 were calcinated at 400 or 600 ”C, the V2O5 nanorods and nanosheets shown in Figure3.2d were obtained; which had typical lengths of about 10 ”m and diameters ranging from 100 to 500 nm. The work here demonstrates that one can synthesize large amounts of vanadium oxide nanomaterials at low temperatures without sophisticated equipment and/or elaborate templates or catalysts through cost-effective synthetic procedures. Because the crystal structures of ammonium vanadates and vanadium oxides have two dimensionally layered structures, V2O5 nanomaterials grow as belts or rods with the directional growth along a particular axis upon calcination of thus grown vanadates. However, the directional growth in a particular axis was found to be inhibited by continuous disturbance by refluxing the solution, which leads to the round flat disk type of the crystallites. This is, to our knowledge, the first systematic demonstration of formation of various nanostructures of vanadates depending on experimental
conditions such as pH of the medium and other reaction conditions. Also, this is the first demonstration that large amounts of nanostructured materials can be prepared without elaborate procedures.
CHAPTER FOUR
4. Conclusion
Nanostructures of V2O5 were prepared by thermal decomposition of hydrated ammonium vanadate nanomaterials. The nanosized hydrated ammonium vanadates were prepared in nano-disk shapes by refluxing in a highly concentrated ammonium solution (sample 1), in nano-rod and belt shapes by evaporation and crystallization from a high pH ammonium solution (sample 2), or by a precipitation method lowering the pH of the ammonium solution (sample 3). While the reflux and precipitation methods can be applicable to large scale production of low-dimensional nanostructured vanadium oxides, the performances of electrodes prepared from their calcinated nanostructures differ significantly. Nanosized V2O5 nano- disks or rods obtained by calcinating the nanostructures obtained by precipitation in acidic media displayed the best performance for Li+ intercalation. To conclude in this project all the planned objectives were completed successfully.
References
Z.-Y.Zhou,N.Tian,J.-T.Li,I.Broadwell,S.-G.Sun,Chem.Soc.Rev.40(2011) 4167’4185.
G. Neri,Sci.Adv.Mater.2(2010)3’15.
Kam, Kinson C., and Anthony K. Cheetham. “Thermochromic VO 2 nanorods and other vanadium oxides nanostructures.” Materials research bulletin 41.5 (2006): 1015-1021.’
Haber, J., M. Witko, and R. Tokarz. “Vanadium pentoxide I. Structures and properties.” Applied Catalysis A: General 157.1-2 (1997): 3-22.
‘ Wang, Nian, et al. “Selected-control hydrothermal synthesis and formation mechanism of 1D ammonium vanadate.” Journal of Solid State Chemistry 181.3 (2008): 652-657.’
Wang, Ying, and Guozhong Cao. “Synthesis and enhanced intercalation properties of nanostructured vanadium oxides.” Chemistry of Materials 18.12 (2006): 2787-2804.’
Sellmyer, David J., and Ralph Skomski, eds. Advanced magnetic nanostructures. Springer Science & Business Media, 2006.’
Aparna, S., et al. “Structural Characterization of High Energy Ball Milled Nanocrystalline Vanadium (V) Oxide (V2O5) Powder.” Advanced Science, Engineering and Medicine 9.3 (2017): 188-194.”
Rao, Chintamani Nagesa Ramachandra, Achim M”ller, and Anthony K. Cheetham, eds. The chemistry of nanomaterials: synthesis, properties and applications. John Wiley & Sons, 2006.’
Leonardi, S. G., et al. “Behavior of sheet-like crystalline ammonium trivanadate hemihydrate (NH 4 V 3 O 8” 0.5 H 2 O) as a novel ammonia sensing material.” Journal of Solid State Chemistry 202 (2013): 105-110.
J.S. Sakamoto,B.Dunn,J.Electrochem.Soc.149(2002)A26’A30.
I.H. Kim,J.H.Kim,B.W.Cho,K.B.Kim,J.Electrochem.Soc.153(2006) A1451’A1458.
H.Y.Wang,K.L.Huang,S.Q.Liu,C.H.Huang,W.J.Wang,Y.Ren,J.PowerSour. 196(2011)788’792.
H.Y.Wang,K.L.Huang,C.H.Huang,S.Q.Liu,Y.Ren,X.B.Huang,J.PowerSour. 196(2011)5645’5650.
H.Y.Wang,K.L.Huang,Y.Ren,X.B.Huang,S.Q.Liu,W.J.Wang,J.PowerSour. 196(2011)9786’9791.
Wang, Nian, et al. “Selected-control hydrothermal synthesis and formation mechanism of 1D ammonium vanadate.” Journal of Solid State Chemistry 181.3 (2008): 652-657.’
Liu, J.; Wang, X.; Peng, Q.; Li, Y. Adv. Mater. 2005, 17, 764.
Pdtkov, V.; Trikalitis, P. N.; Bozin, E. S.; Billinge, S. J. L.; Vogt,T.; Kanatzidis, M. G. J. Am. Chem. Soc. 2002, 124, 10157.
Yao, T.; Oka, Y.; Yamamoto, N. Mater. Res. Bull. 1992, 27,669.
Kannan, A. M.; Manthiram, A. Solid State Ionics 2003, 159,265.
Ren, T.-Z.; Yuan, A.-Y.; Zou, X. Cryst. Res. Technol. 2007, 42,317.22\ Alberto. “X-Ray Diffraction (XRD).” Encyclopedia of Membranes(2015): 1-3.’
Yao, M. H., Baird, R. J., Kunz, F. W., & Hoost, T. E. An XRD and TEM investigation of the structure of alumina-supported ceria’zirconia. Journal of Catalysis, (1997). 166(1), 67-74.’
Razeghi, Manijeh. Scanning Electron Microscope (SEM). NORTHWESTERN UNIV EVANSTON IL, 1996.’
H.T.Evans,S.Block,Inorg.Chem.5(1966)1808’1814.
Lampe-Onnerud, C.; Thomas, J. O. J. Mater. Chem. 1995, 5,1075.
Kong, L.; Liu, Z.; Shao, M.; Xie, Q.; Yu, W.; Qian, Y. J. SolidState Chem. 2004, 177, 690.
Livage, J. Coord. Chem. Rev. 1998, 999, 178.
Mai, L. Q.; Lao, C. S.; Hu, B.; Zhou, J.; Qi, Y. Y.; Chen, W.; Gu, E. D.; Wang, Z. L. J. Phys. Chem. 2006, B 110, 18138.
Twu, J.; Shih, C. F.; Guo, T. H.; Chen, K. H. J. Mater. Chem.1997, 7, 2273.
Hardcastle, F. D.; Wach, I. E. J. Phys. Chem. 1991, 95, 5031.
Chun, I. S., Challa, A., Derickson, B., Hsia, K. J., & Li, X.. Geometry effect on the strain-induced self-rolling of semiconductor membranes. Nano letters, (2010) 10(10), 3927-3932.’
Appendex A: X-ray differaction data
Dataset Name 1
Pos. [”2Th.] Height [cts] FWHM Left [”2Th.] d-spacing [”] Rel. Int. [%]
10.8647 3970.84 0.3011 8.14338 15.14
11.4048 26219.20 0.1338 7.75894 100.00
14.4338 102.59 0.2007 6.13679 0.39
15.5497 3706.58 0.1673 5.69880 14.14
17.9346 898.34 0.0836 4.94600 3.43
20.1465 110.36 0.1004 4.40770 0.42
21.1634 62.34 0.1004 4.19816 0.24
22.8465 622.71 0.1338 3.89254 2.37
24.7407 97.45 0.1338 3.59864 0.37
25.2092 1050.13 0.1673 3.53281 4.01
25.8422 193.89 0.1338 3.44770 0.74
27.5161 778.21 0.1506 3.24165 2.97
27.8520 2172.78 0.1506 3.20332 8.29
29.5619 175.54 0.2007 3.02181 0.67
30.7266 420.59 0.0669 2.90987 1.60
30.9399 755.12 0.1004 2.89029 2.88
31.3063 443.94 0.1338 2.85730 1.69
32.5704 88.82 0.1338 2.74924 0.34
34.0196 114.09 0.1673 2.63536 0.44
34.9051 72.06 0.2007 2.57051 0.27
36.2404 231.46 0.1673 2.47881 0.88
36.8477 111.09 0.1673 2.43933 0.42
37.5963 127.72 0.1673 2.39247 0.49
38.7985 57.28 0.2007 2.32106 0.22
39.5957 49.22 0.2007 2.27615 0.19
40.8825 443.34 0.1506 2.20743 1.69
42.3483 62.34 0.1673 2.13435 0.24
43.0801 26.88 0.2007 2.09978 0.10
44.8852 275.44 0.2007 2.01944 1.05
46.5251 41.70 0.2342 1.95201 0.16
47.7469 79.22 0.1338 1.90488 0.30
48.9723 29.12 0.2007 1.86004 0.11
49.4850 37.44 0.2342 1.84196 0.14
50.6921 101.52 0.2007 1.80090 0.39
52.2299 35.50 0.2676 1.75144 0.14
52.8001 20.92 0.2007 1.73386 0.08
53.7719 32.18 0.5353 1.70480 0.12
55.9421 19.78 0.2676 1.64370 0.08
56.6429 33.87 0.2676 1.62502 0.13
57.5169 58.30 0.1673 1.60239 0.22
58.5418 47.77 0.2676 1.57675 0.18
60.1015 60.91 0.2676 1.53951 0.23
61.0935 15.91 0.4015 1.51687 0.06
62.5745 48.24 0.3346 1.48449 0.18
63.6363 16.37 0.4015 1.46225 0.06
64.6332 9.59 0.4684 1.44209 0.04
65.4914 71.74 0.2007 1.42526 0.27
66.6080 24.30 0.3346 1.40405 0.09
68.0525 17.61 0.8029 1.37773 0.07
Dataset Name 2
Ref. Code Chemical Formula Mineral Name
98-001-5984 O5 V2 Shcherbinaite
Pos. [”2Th.] Height [cts] FWHM Left [”2Th.] d-spacing [”] Rel. Int. [%]
11.3495 238.00 0.1004 7.79657 5.16
15.4200 2702.96 0.1338 5.74646 58.55
20.3527 4616.72 0.1840 4.36350 100.00
21.7978 984.83 0.0836 4.07738 21.33
23.9778 44.40 0.5353 3.71139 0.96
25.6160 172.37 0.1673 3.47762 3.73
26.2268 2791.50 0.1673 3.39801 60.47
31.0824 1369.74 0.1171 2.87737 29.67
32.4424 543.61 0.2342 2.75979 11.77
33.3926 160.79 0.2007 2.68340 3.48
34.3414 616.76 0.1171 2.61140 13.36
36.0307 43.06 0.2342 2.49275 0.93
37.4634 44.31 0.2007 2.40065 0.96
41.2991 182.44 0.3011 2.18612 3.95
42.1318 90.40 0.1673 2.14482 1.96
45.5212 133.50 0.2676 1.99270 2.89
47.3825 238.59 0.2676 1.91867 5.17
47.9844 100.99 0.1506 1.89600 2.19
48.8508 104.91 0.2007 1.86438 2.27
49.5912 26.74 0.2007 1.83827 0.58
50.6969 37.57 0.2007 1.80074 0.81
51.2575 260.89 0.2676 1.78235 5.65
52.0882 94.13 0.2007 1.75587 2.04
53.8661 16.73 0.3346 1.70204 0.36
55.6444 82.59 0.3011 1.65179 1.79
56.3458 29.98 0.2007 1.63288 0.65
59.0879 47.30 0.4015 1.56348 1.02
60.1921 11.64 0.3346 1.53741 0.25
61.1436 95.87 0.1673 1.51575 2.08
62.1673 110.91 0.3011 1.49323 2.40
64.6265 31.16 0.3346 1.44222 0.67
66.1485 35.67 0.3346 1.41268 0.77
67.8147 16.22 0.4015 1.38198 0.35
Sample Identification 3
Pos. [”2Th.] Height [cts] FWHM Left [”2Th.] d-spacing [”] Rel. Int. [%]
9.0764 291.29 0.4015 9.74342 100.00
13.3379 18.46 0.8029 6.63845 6.34
25.6222 111.31 0.2676 3.47680 38.21
26.4438 169.88 0.2676 3.37061 58.32
29.3862 28.42 0.8029 3.03947 9.76
32.6748 17.85 0.8029 2.74069 6.13
36.3887 17.04 0.8029 2.46904 5.85
50.8698 117.61 0.4684 1.79503 40.38
Dataset Name 4
Pos. [”2Th.] Height [cts] FWHM Left [”2Th.] d-spacing [”] Rel. Int. [%]
15.0684 374.50 0.0836 5.87974 3.53
18.1351 511.27 0.1506 4.89176 4.82
21.4769 513.21 0.1506 4.13756 4.84
22.8970 3646.21 0.0816 3.88086 34.40
22.9740 4747.13 0.0836 3.87122 44.78
23.6050 170.17 0.1338 3.76915 1.61
28.2053 433.56 0.1171 3.16398 4.09
29.4357 34.39 0.2007 3.03448 0.32
30.7188 217.77 0.1171 2.91060 2.05
32.6758 10600.49 0.1020 2.73834 100.00
32.7749 4689.93 0.0408 2.73707 44.24
34.1129 111.75 0.2040 2.62619 1.05
36.6586 89.12 0.1632 2.44945 0.84
40.2712 658.06 0.0816 2.23766 6.21
42.8679 31.24 0.3264 2.10794 0.29
46.7960 946.82 0.0612 1.93973 8.93
46.9037 1317.50 0.0612 1.93553 12.43
50.9412 16.12 0.3264 1.79119 0.15
52.8507 290.84 0.2244 1.73089 2.74
56.6498 8.45 0.8160 1.62349 0.08
58.1999 263.31 0.1020 1.58389 2.48
58.3149 389.04 0.0612 1.58104 3.67
58.4710 182.38 0.0612 1.58111 1.72
59.8608 12.36 0.3264 1.54385 0.12
63.8190 11.71 0.4896 1.45730 0.11
68.4295 163.75 0.1632 1.36992 1.54
68.6282 86.05 0.0612 1.36983 0.81
Ref. Code Chemical Formula Mineral Name
01-075-9978 V2 O5 Shcherbinaite, syn
Pattern List: (Bookmark 4)
Pos. [”2Th.] Height [cts] FWHM Left [”2Th.] d-spacing [”] Rel. Int. [%]
15.5106 2688.01 0.1506 5.71308 78.51
20.3977 3423.84 0.2007 4.35397 100.00
21.8497 863.34 0.0836 4.06780 25.22
25.6588 148.74 0.1338 3.47192 4.34
26.2931 2936.70 0.1506 3.38959 85.77
31.1533 1363.86 0.1506 2.87098 39.83
32.5050 577.68 0.1338 2.75462 16.87
33.4561 170.03 0.2007 2.67845 4.97
34.3890 601.89 0.1020 2.60574 17.58
34.4794 662.51 0.0669 2.60127 19.35
36.1183 49.26 0.2007 2.48690 1.44
37.4841 44.89 0.2007 2.39937 1.31
41.3892 166.07 0.2676 2.18157 4.85
42.1524 72.48 0.3680 2.14382 2.12
45.6063 150.00 0.2676 1.98917 4.38
47.4253 246.22 0.2342 1.91704 7.19
47.9842 95.54 0.2676 1.89601 2.79
48.9419 101.91 0.3011 1.86112 2.98
49.6797 24.76 0.2676 1.83520 0.72
51.3254 286.18 0.2175 1.78016 8.36
52.1049 98.47 0.1673 1.75535 2.88
53.9000 28.14 0.1338 1.70105 0.82
55.7399 89.99 0.3680 1.64918 2.63
56.4233 28.31 0.2676 1.63082 0.83
58.6256 37.75 0.2007 1.57470 1.10
59.1713 55.29 0.2676 1.56147 1.61
60.2163 16.45 0.2676 1.53685 0.48
61.1947 109.72 0.2007 1.51461 3.20
62.2045 120.01 0.2007 1.49243 3.51
64.7131 27.35 0.4684 1.44050 0.80
66.1765 37.43 0.3346 1.41215 1.09
67.8578 13.70 0.4015 1.38120 0.40
Document History: (Bookmark 5)
Dataset Name 4
File name D:\XRD 2017\Chemistry\CAARU-17-228-I\4.xrdml
Sample Identification 4
Measurement Date / Time 22-Mar-17 2:03:27 PM
Raw Data Origin XRD measurement (*.XRDML)
Scan Axis Gonio
Start Position [”2Th.] 5.0184
End Position [”2Th.] 69.9754
Step Size [”2Th.] 0.0170
Scan Step Time [s] 50.1650
all samples together
Appendix B: spectroscopic data (IR)
Sample1
Sample2
Sample3
Appendix C: SEM data