Morphology and Oxidation State Transitions under Hydrothermal Treatment on Vanadium Oxide (V) Systems | Chapter 1 | Current Innovations in Chemical and Materials Sciences Vol. 5

This chapter revisits the review in expanded form of “Hydrothermal Synthesis of Vanadium Oxide Microstructures with Mixed Oxidation States” which summarizes many vanadium oxide micro and nano structures displaying different morphologies and V4+ / V5+ rates, most of the synthetic procedures are related to sol – gel synthesis executed with different V5+ oxide precursors namely V2O5, VO(OCH2CH3)3, NH4VO3 and VOCl3 in presence of different organic molecules, most of them acting as templates under self – assembled processes depending on their distinctive features, like surfactants (amphiphilic molecules), reducing agents and coordination ligands, under certain chemical parameters and conditions such as pH, concentration, stoichiometry, water / solvent rate at specific temperatures, which usually leads to different routes like layered intercalation compounds nanocomposites, semi or complete reduced vanadium oxide systems or coordinated systems directed under different building blocks that are predominant in the environmental chemical system. Once the first stage is completed hydrothermal treatment takes place and many processes occurred under higher temperature, pressure changes and time frame reactions, the resultant products display magnificent 1 – D, 2 – D and 3 – D morphologies, with different oxidations states rates and most of these structures are based in different structural vanadium oxides lattices that are able to withstand each system, like V7O162-, V2O4, V6O11 and V4O92-. This chapter focuses on the chemical stages that take place in previous and subsequent to hydrothermal treatment stages and analyses the possible redox reactions and species that could potentially display a major role in the formation of these intricate structures for the purpose of understanding the characteristic for future applications in many technological fields.

Author(s) Details:

Daniel Navas,
Instituto de Ciencias Naturales, Facultad de Medicina Veterinaria y Agronomía, Universidad de Las Américas, Sede Providencia, Avenida Manuel Montt 948, Santiago 7500975, Chile.

Please see the link here: https://stm.bookpi.org/CICMS-V5/article/view/13124

Study on Preparation of Various Morphologies of ZnO Nanostructure through Wet Chemical Method | Chapter 9 | Recent Trends in Chemical and Material Sciences Vol.7

 Zinc oxide (ZnO) nanopowders are synthesised using a hydrothermal technique and a solution reaction method. The generated products had one of four possible morphologies depending on the precursors and preparation conditions: nanoparticle, microrod, nanoplate, or nanotube. In this paper, we present the results of our inquiry into the preparation of ZnO nanostructures using a template-free aqueous solution-based simple chemical approach. The precursor for ZnO nanostructures was zinc nitrate hexahydrate Zn(NO3)2.6H2O. A hydrothermal technique was used to make ZnO microrods and nanoplates utilising Zn(NO3)2 and KOH as reaction ingredients. A chemical reaction between Zn(NO3)2 and NH4OH produced ZnO nanotubes. ZnO nanoparticles were made from zinc nitrate and ammonium carbonate (NH4)2CO3 in aqueous solution using the precipitation method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy were used to analyse the structures, morphology, and element components of these ZnO products manufactured using the aforementioned approaches (EDS). As-prepared ZnO nanoparticles have an average diameter of 30-60 nm; rod-like ZnO has an average diameter of about 350 nm and a length of 3.5 mm; plate-like ZnO has an average thickness of about 40 nm and a lateral size of 200'400 nm; and ZnO nanotubes have an outer diameter of about 400 nm and an inner diameter of about 300 nm and a length of about 4 mm According to the XRD data, all four morphologies of ZnO have a wurtzite structure. The wet chemical method is shown to be extremely promising for producing ZnO nanocrystallines with a variety of morphologies. Our research contributes to the field of ZnO nanostructures research, and it can be utilised to investigate possible applications in gas sensors, photocatalysts, SERS substrates, and optoelectronic devices.

Author(s) Details:

Nguyen Dac Dien,
Vietnam Trade Union University, 169 Tay Son Street, Dong Da District, Ha Noi City, Viet Nam.

Please see the link here: https://stm.bookpi.org/RTCAMS-V7/article/view/6102