Chemical Vapor Synthesis and Physico‐chemical Properties of V₂O₅ Nanoparticles

Abstract

In the field of heterogeneous catalysts, nanometer-size transition metal oxides are of great interest. In particular, vanadium oxide-based materials, including vanadium pentoxide (V 2 O 5 ) and vanadium phosphates, are catalysts for the mild oxidation of hydrocarbons and alcohols.[1] To date, V 2 O 5 has attracted increasing interest for its potential applications as catalysts, sensors, and electrodes. V 2 O 5 powders can be obtained by various physical and chemical methods, such as CVD, [2][3][4] hydrothermal method, [1,3,5] spray pyrolysis, [6] sol-gel, [7][8][9] co-precipitation, [10] and microwave plasma-torch method, [11] etc. Chemical vapor synthesis, also known as CVD or chemical vapor condensation (CVC), [12][13][14] is an alternative method for the direct synthesis of nanoparticles. The principle advantages of the reactions in the gas phase are, very short process times, and nanometer-scale powders of high purity with a narrow particle size distribution. The particle morphology, crystalline phase, and surface chemistry of thermally decomposed particles can be controlled by regulating the precursor composition, reaction temperature, pressure, solvent property, and aging time. [15,16] In a typical CVC process, the precursor solution is atomized into an aerosol reactor (electric furnace) where droplets undergo solvent evaporation and solute precipitation within the droplets, which are then dried. In a typical thermal decomposition process, the precursor solution was atomized into an aerosol reactor, where droplets underwent solvent evaporation and solute precipitation within the droplets, which were then dried, followed by thermolysis of the precipitates at higher temperatures, and finally sintering to form the final particles.[15]In the CVC process, the synthesis temperature is one of the most important factors for determining the particle morphology, such as the crystal phase, size, specific surface area, surface composition, and chemical state. [15,17] In this study, V 2 O 5 nanoparticles were obtained by the thermal decomposition of a vanadium oxytriethoxide (VOTE) solution. The detailed microstructural characteristics of the thermally decomposed nanoparticles were examined as a function of the synthesis temperatures (500-1300 8C). Figure 1a shows X-ray diffraction (XRD) patterns of the V 2 O 5 nanoparticles prepared at each synthesis temperature. The XRD patterns of the V 2 O 5 samples synthesized at 900, 1100, and 1300 8C showed similar patterns with different peak intensities, and indicated a single-Shcherbinaite phase with an orthorhombic structure (JCPDS Card No. 41-1426) and lattice parameters of a ¼ 1.1516 nm, b ¼ 0.332 nm, and c ¼ 0.43727 nm. [8,10] In addition, the peak intensities of the V 2 O 5 samples increased with increasing synthesis temperature to 900 and 1300 8C, indicating enhanced crystallization. The peaks (001) intensity became higher and the peak shape narrower, indicating an increase in V 2 O 5 crystallite or grain size, which was calculated from the line broadening of (001) dif...

Recent advances in vanadium pentoxide (V2O5) towards related applications in chromogenics and beyond: fundamentals, progress, and perspectives

“…(ii) Chemical vapor deposition. This technique including CVD, [113][114][115][116] AP-CVD, 117 LP-CVD, 118 AL-CVD, 119 MO-CVD, 120 PE-CVD, 121 and AA-CVD 122 is based mainly on the vapor phase reaction-adsorbed precursors (i.e., VO(acac) 2 , V(C 5 H 8 O 2 ) 3 , and VO(OC 2 H 5 ) 3 ) on the substrate surface. 50 The reaction temperature, O 2 source, reaction time, and sample position are factors that play an important role in controlling the morphology, crystal structure, and surface of the thin film.…”

“…50 The reaction temperature, O 2 source, reaction time, and sample position are factors that play an important role in controlling the morphology, crystal structure, and surface of the thin film. 50,113 Among these factors, the deposition temperature is used to control the morphology and thickness of the film. When the deposition temperature was increased from 320 1C to 420 1C for the same duration, the length of V 2 O 5 NWs increased from 10 mm to 100 mm while the widths remained approximately 80 nm.…”

Recent Advances in Nanostructured Vanadium Oxides and Composites for Energy Conversion

“…Chemical vapor condensation (CVC) is a similar technique, but using high temperature instead of flame. [69] Also, the vaporized chemicals could be deposited onto V 2 O 5 surfaces directly by repeating the CVC processes. [72] Similar techniques such as pulsed laser ablation a ambient [70] and hydrolysis deposition [71] have also been reported to prepare 0D V 2 O 5 nanostructures.…”

“…The precursor solutions will be vaporized, then condensed and crystallized into nanoparticles within seconds. Chemical vapor condensation (CVC) is a similar technique, but using high temperature instead of flame . Also, the vaporized chemicals could be deposited onto V 2 O 5 surfaces directly by repeating the CVC processes .…”

A Novel and One‐pot Green Synthesis of Vanadium Oxide Nanorods Using a Phytomolecule Isolated from Phyllanthus amarus

“…The useful properties of V 2 O 5 can be even more motivating in the nanomaterials and technology . V 2 O 5 nanoparticles can be synthesized by various physical and chemical methods, viz., CVD, hydrothermal method, spray sol‐gel, co‐precipitation etc. Recently, the green synthesis of V 2 O 5 nanobelts with around 20–40 nm width using plant material, tannic acid was reported .…”