Calciothermic reduction of titanium dioxide and molybdenum trioxide under pressure of nitrogen gas

2017 ◽  
Vol 26 (1) ◽  
pp. 80-82 ◽  
Author(s):  
A. N. Avramchik ◽  
B. Sh. Braverman ◽  
Yu. M. Maksimov ◽  
L. N. Chukhlomina
Keyword(s):  
Titanium Dioxide ◽  
Molybdenum Trioxide ◽  
Nitrogen Gas ◽  
Calciothermic Reduction

A Study of Tio2 Aerogels Pore and Ramified Structure by Small-Angle Neutron Scattering

1994 ◽  
Vol 376 ◽  
Author(s):  
Zhu Zhu ◽  
Min Lin ◽  
Geula Dagan ◽  
Micha Tomkiewicz
Keyword(s):  
Titanium Dioxide ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Gas Adsorption ◽  
Scattering Data ◽  
Morphological Parameters ◽  
Nitrogen Gas ◽  
Light Density ◽  
Sans Data

ABSTRACTThe microstructral characteristics of titanium dioxide aerogels were studied by Small Angle Neutron Scattering (SANS). A variety of models were used to extract the morphological parameters from the SANS data. The evaluation of scattering data was found to be consistent with nitrogen gas adsorption and TEM measurements of a model of aerogel consisting of a light density matrix in which meso- and macro-pores are embedded.

Simulation on Calciothermic Reduction Process of Titanium Dioxide

2014 ◽  
pp. 483-490
Author(s):  
Baoqiang Xu ◽  
Jinyang Zhao ◽  
Bin Yang ◽  
Xiumin Chen ◽  
Dongsheng Wang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Reduction Process ◽  
Calciothermic Reduction

scholarly journals Can Doping of Transition Metal Oxide Cathode Materials Increase Achievable Voltages with Multivalent Metals?

2019 ◽  
Author(s):  
Daniel Koch ◽  
Sergei Manzhos
Keyword(s):  
Titanium Dioxide ◽  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
High Performance ◽  
Molybdenum Trioxide ◽  
Type Systems ◽  
Hole Doping ◽  
Earth Abundant ◽  
Valence Bands

We investigate from first principles the use of substitutional p-doping as a means to enhance the insertion energies of multivalent metals in transition metal oxides, and therefore the resulting voltages in an electrochemical cell, due to bandstructure modulation. Multivalent and earth-abundant metals such as magnesium or aluminium are attractive candidates to replace lithium in future high-performance secondary batteries with intercalation-type electrodes. Unfortunately, the achievable voltages obtained with this kind of elements still remain uncompetitively low. We study and compare the changes in insertion energetics (voltages) of single- and multivalent metals in semiconducting and insulating transition metal oxides upon substitutional p-doping with different metals, introducing different numbers of hole states. We use a single vanadium pentoxide monolayer as model system to study the effect of p-doping on achievable voltages and deduce general trends for transition metal oxides. Our investigations reveal the formation of n-hole polarons (with n>1) in form of oxygen dimers in p-doped vanadia caused by localized <i>p</i> holes on oxide ions in agreement with previous findings. We find that the oxygen dimer formation has an adverse effect on adsorption energetics compared to the single-hole case without dimerization. We find an analogous oxygen dimerization in other TMOs with oxygen-dominated valence bands like molybdenum trioxide and titanium dioxide, while strained systems like trigonal nickel- or titanium dioxide, or Mott-type systems like monoclinic vanadium dioxide with qualitatively different valence band composition do not exhibit oxygen dimerization with multi-hole doping. Our results demonstrate the advantages and limitations of TMO electrode p-doping and show a path to possible strategies to overcome detrimental effects.

scholarly journals Impacts of Mixing Mode on Photocatalytic Reduction of Hexavalent Chromium over Titanium Dioxide Nanomaterial under Various Environmental Conditions

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2291
Author(s):  
Chih-Chi Yang ◽  
Khanh-Chau Dao ◽  
Yo-Sheng Lin ◽  
Teng-Yun Cheng ◽  
Ku-Fan Chen ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Hexavalent Chromium ◽  
Species Distribution ◽  
Uv Light ◽  
Photocatalytic Reduction ◽  
Oxygen Effect ◽  
Strong Interactions ◽  
Nitrogen Gas ◽  
Key Factor ◽  
Hole Scavenger

This study explores the effects of initial Cr(VI) concentration, wavelength, hole-scavenger (absence and presence of salicylic acid), and oxygen conditions (aeration by air, nitrogen gas, and mechanical stir only) on photocatalytic reduction of hexavalent chromium over titanium dioxide photocatalyst and the chromic species distribution after photocatalysis. The experimental results show the existence of strong interactions between these factors. The factor of hole-scavenger was more important than the UV light wavelength condition for a reduction of 3 mg Cr(VI) L−1, whereas both factors became important when Cr(VI) concentration increased to 20 mgL−1. The higher the UV wavelength was, the less the amount of chromium retained on the TiO2 surface. The influence of oxygen-containing conditions in the solution on the reduction of 3 mgL−1 Cr(VI) was unobvious, whereas its influence became remarkable for the reduction of 20 mgL−1 Cr(VI) in the presence of SA. The interaction between oxygen-containing factor and other environmental factors, such as Cr(VI) concentration and scavenger presence (SA in this study), is a key factor about the degree of oxygen effect on Cr(VI) photo-reduction and the chromic species distribution. Simple stirring obtained better photocatalytic efficiency than aeration by air or nitrogen gas.

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