Effect of transition metal oxides (CuO, Fe2O3, Bi2O3) on the combustion and thermal decomposition of potassium nitrate-based molecular perovskite energetic material

In-depth research has found that the nanocrystal facet of transition metal oxides (TMOs) greatly affects their heterogeneous catalytic performance, as well as the property of photocatalysis, gas sensing, electrochemical reaction, etc. that are all involved in chemical conversion processes. Therefore, the facet-dependent properties of TMO nanocrystals have been fully and carefully studied by combining systematic experiments and theoretical calculations, and mechanisms of chemical reactions are accurately explained at the molecular level, which will be closer to the essence of reactions. Evidently, as an accurate investigation on crystal facets, well-defined TMO nanocrystals are the basis and premise for obtaining relevant credible results, and shape-controlled synthesis of TMO nanocrystals thereby has received great attention and development. The success in understanding of facet-dependent properties and shape-controlled synthesis of TMO nanocrystals is highly valuable for the control of reaction and the design of high-efficiency TMO nanocrystal catalysts as well as other functional materials in practical applications.

Effect of transition metal oxides on mullite whisker formation from mechanochemically activated powders

Catalytic effects of transition metal oxides on HTPB-based fuel polymer matrices

Effect of the transition metal oxide supports on hydrogen production from bio-ethanol reforming

Effects of transition metal oxides on the densification of thin-film GDC electrolyte and on the performance of intermediate-temperature SOFC

Silicon nitride on steel sliding contacts may provide advantageous tribological properties over traditional self-mated pairs, however the friction and wear behavior at high sliding speeds (>1 m/s) is not well understood. Previous studies at low sliding speeds (< 1 m/s) have found that the wear mechanisms change as a function of the operating parameters, e.g. atmosphere, sliding speed, load, and temperature, due to the formation of transition metal oxides such as Fe2O3 and Fe3O4. This study detected transient effects of the dry silicon nitride on steel contact over a range of sliding speeds to understand their relation to tribochemical reactions and the resulting tribological behavior. Two sets of dry silicon nitride on steel experiments were conducted at 1.45 GPa maximum Hertzian pressure. The first set were low sliding speed reciprocating experiments, conducted at an average of 0.06 m/s, conducted at variable operating temperature, ranging from 23 °C to 1000 °C. In the low sliding speed experiments, transitions of the wear mechanism from adhesive wear, to abrasive wear, then to oxidative wear was observed when the operating temperature increased. The second set were high sliding speed experiments, conducted at variable sliding speeds, ranging from 1 m/s to 16 m/s. In the high sliding speed experiments, a transition from adhesive wear to oxidative wear was observed when the sliding speed surpassed 4.5 m/s. The high sliding speed experiments were accompanied by in-situ instrumentation which detected the presence of a tribofilm which correlated to a reduction in friction, and its formation was linked to tribochemical reactions induced by high flash temperatures. Both sets of experiments had a maximum estimated contact temperature of 1000 °C where oxidative wear was prevalent. Although, the low sliding speed experiments underwent severe bulk oxidation and thermal softening effects, while the high sliding speed experiments experienced localized flash heating events with temperatures sufficient to form a semi-coherent tribofilm that was lubricious and significantly improved wear resistance. Therefore, the effects of transition metal oxides in sliding contacts are determined to be significantly influenced on their mechanisms of formation and interrelated to the operating parameters as found for dry sliding silicon nitride on steel contacts.

The effect of transition metal oxides and the sintering temperature on the strength parameters of cordierite ceramics synthesized using mechanical activation is investigated. It is established that an introduction of oxide additives improves the strength of ceramics.

First, the effect of transition metal oxide (e.g., V2O5, Co2O3, etc.) on the physical properties (e.g., density, glass transition temperature (Tg), optical properties and mechanical properties) and chemical durability of a simplified borosilicate nuclear waste glass was investigated. Adding V2O5 in borosilicate nuclear waste glasses decreases the Tg, while increasing the fracture toughness and chemical durability, which benefit the future formulation of nuclear waste glasses. Second, structural study of ZrO2/SiO2 substitution in silicate/borosilicate glasses was systematically conducted by molecular dynamics (MD) simulation and the quantitative structure-property relationships (QSPR) analysis to correlate structural features with measured properties. Third, for bioactive glass formulation, mixed-network former effect of B2O3 and SiO2 on the structure, as well as the physical properties and bioactivity were studied by both experiments and MD simulation. B2O3/SiO2 substitution of 45S5 and 55S5 bioactive glasses increases the glass network connectivity, correlating well with the reduction of bioactivity tested in vitro. Lastly, the effect of optical dopants on the optimum analytical performance on atom probe tomography (APT) analysis of borosilicate glasses was explored. It was found that optical doping could be an effective way to improve data quality for APT analysis with a green laser assisted system, while laser spot size is found to be critical for optimum performance. The combined experimental and simulation approach adopted in this dissertation led to a deeper understanding of complex borosilicate glass structures and structural origins of various properties.

Effects of transition metal oxides on the formation of meso-porous structures in micro-spherical activated carbon for use in electric double layer capacitors

Effects of transition metal oxides on pyrolysis properties of PVC

Effect of transition metal oxides on the thermal conductivity of glass

There is little available research on how different transition metal oxides influence the behavior of B4C-based ceramics, especially for Ta2O5 and Nb2O5. B4C-MeB2 (Me = Ti, Zr, Nb, and Ta) multiphase ceramic samples were prepared via in situ pressureless sintering at 2250 °C, involving the mixing of B4C and MeOx powders, namely TiO2, ZrO2, Nb2O5, and Ta2O5. The phase constituents, microstructures, and mechanical properties of the samples were tested. The results indicated that different transition metal elements had different effects on the ceramic matrix, as verified through a comparative analysis. Additionally, the doped WC impurity during the ball milling process led to the production of (Me, W)B2 and W2B5, which brought about changes in morphology and performance. In this study, the Ta2O5-added sample exhibited the best performance, with elastic modulus, flexural strength, Vickers hardness, and fracture toughness values of 312.0 GPa, 16.3 GPa, 313.0 MPa, and 6.08 MPa·m1/2, respectively. The comprehensive mechanical properties were better than the reported values when the mass fraction of the second phase was around five percent.

Effect of transition metal oxides on densification and electrical properties of Si-containing Ce 0.8Gd 0.2O 2− δ ceramics

Mechanistic studies on the pyrolysis and combustion of polystyrene/ammonium perchlorate propellants in the presence of transition metal oxides

Transition metal oxide-based pseudocapacitors fundamentally involve fast charge–discharge processes due to the fast-Faradaic redox reactions occurring at the interface between the active material and electrolyte. Thus, they exhibit high specific capacity and energy density compared to electrical double-layer capacitors. However, their poor conductivity and low surface area restricted their advanced application in supercapacitors. Therefore, to improve conductivity and surface area without losing pseudocapacity, a synergistic effect of transition metal oxides and electronically conducting polymers has been recognized to design composite electrode materials for supercapacitor. The formation of transition metal oxide-conducting polymer composite electrodes can achieve better electrical conductivity and electrochemical accessibility of redox sites for high-performance supercapacitors. Therefore, this chapter provides decent and updated coverage on synthesis, structure, properties, and supercapacitor performance of conducting polymers and their composites of transition metal oxides.