A method for preparing a niobium, titanium or vanadium metal oxide nanostructured material is provided. The method comprises providing an aqueous reagent comprising (i) a soluble metal oxalate, and/or (ii) oxalic acid and a metal oxide precursor, adding a buffering agent to the aqueous reagent to form a mixture, and heating the mixture under hydrothermal conditions to obtain the metal oxide nanostructured material. The metal oxide nanostructured material may also be doped with a dopant metal such as titanium to enhance capacity and cycling stability. An electrode comprising the metal oxide nanostructured material, and an electrochemical cell containing the electrode are also provided.

The present disclosure relates to a method for producing metal oxide nanoparticles includes a first step of preparing a reaction solution containing a metal complex, an alcohol, and water; a second step of heating the reaction solution for phase-separation under a hermetically sealed atmosphere where the volumetric expansion ratio of the reaction solution reaches 5 to 15%; a third step of holding the reaction solution heated in the second step for 30 minutes or more for dehydrating the metal complex to precipitate the metal oxide nanoparticles; and a fourth step of collecting the metal oxide nanoparticles after the metal oxide nanoparticles are cooled.

The invention concerns a continuous flow process for manufacturing surface modified metal oxide nanoparticles by supercritical solvothermal synthesis in an reaction medium flowing within a continuous flow chamber, said continuous flow chamber containing a hydrolysis area and a supercritical area, said process comprising the introduction of a flow of metal oxide precursor into the continuous flow chamber at a point P located in the hydrolysis area or in the supercritical area, and the introduction of a flow of is located downstream of P1 with respect to the flow direction, as well as the device for carrying out this process.

A production method for metal oxide particles includes: obtaining precursor particles of a metal oxide by performing a synthesis reaction of the precursor particles in the presence of an organic compound; and converting the obtained precursor particles into metal oxide particles by heating an aqueous solution containing the precursor particles to 300° C. or higher and pressurizing the aqueous solution at a pressure of 20 MPa or higher.

A production method for metal oxide particles includes: obtaining precursor particles of a metal oxide by performing a synthesis reaction of the precursor particles in the presence of an organic compound; and converting the obtained precursor particles into metal oxide particles by heating an aqueous solution containing the precursor particles to 300 C. or higher and pressurizing the aqueous solution at a pressure of 20 MPa or higher.

The present disclosure relates to a method for producing metal oxide nanoparticles includes a first step of preparing a reaction solution containing a metal complex, an alcohol, and water; a second step of heating the reaction solution for phase-separation under a hermetically sealed atmosphere where the volumetric expansion ratio of the reaction solution reaches 5 to 15%; a third step of holding the reaction solution heated in the second step for 30 minutes or more for dehydrating the metal complex to precipitate the metal oxide nanoparticles; and a fourth step of collecting the metal oxide nanoparticles after the metal oxide nanoparticles are cooled.

A method for preparing a niobium, titanium or vanadium metal oxide nanostructured material is provided. The method comprises providing an aqueous reagent comprising (i) a soluble metal oxalate, and/or (ii) oxalic acid and a metal oxide precursor, adding a buffering agent to the aqueous reagent to form a mixture, and heating the mixture under hydrothermal conditions to obtain the metal oxide nanostructured material. The metal oxide nanostructured material may also be doped with a dopant metal such as titanium to enhance capacity and cycling stability. An electrode comprising the metal oxide nanostructured material, and an electrochemical cell containing the electrode are also provided.

A process is disclosed for the oxidation and thermal decomposition of metal chlorides, leading to an efficient and effective separation of nuisance elements such as iron and aluminum from value metals such as copper and nickel. In the first instance, oxidation, especially for iron, is effected in an electrolytic reactor, wherein ferrous iron is oxidised to ferric. In a second embodiment, the oxidised solution is treated in a hydrothermal decomposer reactor, wherein decomposable trivalent metal chlorides form oxides and divalent metal chlorides form basic chlorides. The latter are soluble in dilute hydrochloric acid, and may be selectively re-dissolved from the hydrothermal solids, thereby effecting a clean separation. Hydrochloric acid is recovered from the hydrothermal reactor.

The disclosure provides relates to compositions and methods for water treatment. It also addresses a method for synthesizing TiO.sub.2 (and other metal oxides) with or without dopants. This method enables control over size, phase, morphology and porosity and specific surface area of these materials. The disclosure also provides metal oxide composites that can be used in photocatalysts, photovoltaics, energy storage materials (e.g., Li-ion anodes), and solar hydrogen applications.