Solution-phase (e.g., homogeneous) or surface-immobilized (e.g., heterogeneous) electrode-driven oxidation catalysts based on iridium coordination compounds which self-assemble upon chemical or electrochemical oxidation of suitable precursors and methods of making and using thereof are. Iridium species such as {[Ir(LX).sub.x(H.sub.2O).sub.y(μ-O)].sub.z.sup.m+}.sub.n wherein x, y, m are integers from 0-4, z and n from 1-4 and LX is an oxidation-resistant chelate ligand or ligands, such as such as 2(2-pyridyl)-2-propanolate, form upon oxidation of various molecular iridium complexes, for instance [Cp*Ir(LX)OH] or [(cod)Ir(LX)] (Cp*=pentamethylcyclopentadienyl, cod=cis-cis,1,5-cyclooctadiene) when exposed to oxidative conditions, such as sodium periodate (NaIO.sub.4) in aqueous solution at ambient conditions.

A fuel cell catalyst layer includes an SnO.sub.2 support usable in a wide range of humidity environments and provides high power generation from low to high loads. A production method includes the steps of preparing a catalyst composite of an SnO.sub.2 support and platinum or a platinum alloy supported on a surface thereof, and an ionomer that is a proton-conductive polymer; mixing the catalyst composite, the ionomer and a dispersion medium containing at least water and an alcohol having 3 or 4 carbon atoms where the alcohol content is higher than the water, and where a mass ratio (I/MO)) of the ionomer to the SnO.sub.2 support is 0.06 to 0.12, and a solid content of the catalyst composite and the ionomer is 24% by mass or more; and dispersing aggregates of the catalyst composite and the ionomer in the dispersion medium by pulverizing by shear force, while preventing reaggregation of the aggregates by applying force.

The present specification relates to a carrier-nanoparticle complex and a preparation method thereof.

To spread the use of catalysts for fuel cells, there is a demand to develop a catalyst that uses less Pt and has a high power generation efficiency. An electrode catalyst includes a support particle containing a metal oxide and a precious-metal alloy supported on the support particle. The support particle includes multiple branches, a hole between the branches, and a pore. The pore is surrounded by the branches and the hole. The precious-metal alloy includes a precious metal element and at least one or more transition elements.

A method of growing crystals on two-dimensional layered material is provided that includes reversibly hydrogenating a two-dimensional layered material, using a controlled radio-frequency hydrogen plasma, depositing Pt atoms on the reversibly hydrogenated two-dimensional layered material, using Atomic Layer Deposition (ALD), where the reversibly hydrogenated two-dimensional layered material promotes loss of methyl groups in an ALD Pt precursor, and forming Pt-O on the reversibly hydrogenated two-dimensional layered material, using combustion by O.sub.2, where the Pt-O is used for subsequent Pt half-cycles of the ALD process, where growth of Pt crystals occurs.

The present invention refers to a method of treating a platinum-alloy catalyst, comprising the steps of: A) providing a platinum-alloy catalyst, which comprises platinum (Pt) and at least one metal (M), which is less noble than platinum; B) exposing the catalyst to an acidic or basic medium, and exposing the catalyst to an adsorptive gas, wherein during step B) the catalyst is not subjected to an external electrical current or voltage. Further, the invention refers to a treated platinum-alloy catalyst. Moreover, and a device for carrying out the method of treating the platinum-alloy catalyst is provided.

A fuel cell includes a proton-exchange membrane, and a cathode and anode fixed on its opposite sides. The anode delimits a flow conduit between a molecular-oxygen inlet area and a water outlet area. The cathode includes a support for catalyst material. The support has first and second materials to which catalyst is fixed, the first material being a graphitized material. The second material has a resistance to corrosion by oxygen that is greater than that of the first material. A quantity of the second material at the inlet area is greater than a quantity of the second material at the water outlet. The cathode comprises a first layer including the first material and a second layer including the second material. A thickness of the second layer decreases between the molecular-oxygen inlet area and the water outlet area.

The present invention provides a method for fabricating core-shell particles supported on a carrier, the method including: forming a solution by adding a first metal supported on a carrier to a solvent; adjusting a pH of the solution from 7 to 14 and adding a metal salt of a second metal thereto; and forming core-shell particles by adding a reducing agent to the solution and forming a shell including the second metal on a surface of a core particle including the first metal, and core-shell particles fabricated by the method.

A method is disclosed for preparing a metal single-atom catalyst for a fuel cell including the steps of depositing metal single atoms to a nitrogen precursor powder, mixing the metal single atom-deposited nitrogen precursor powder with a carbonaceous support, and carrying out heat treatment. The step of depositing metal single atoms is carried out by sputtering, thermal evaporation, E-beam evaporation or atomic layer deposition. The method uses a relatively lower amount of chemical substances as compared to conventional methods, is eco-friendly, and can produce a single-atom catalyst at low cost. In addition, unlike conventional methods which are limited to certain metallic materials, the present method can be applied regardless of the type of metal.

A catalyst layer for a fuel cell contains a support and a catalyst supported on the support. The support contains a titanium oxide having a crystal phase of Ti.sub.2O. The ratio of total abundance of trivalent Ti and divalent Ti (W2) to abundance of tetravalent Ti (W1), W2/W1, is 0.1 or more as determined on the surface of the catalyst layer by X-ray photoelectron spectroscopy. The catalyst is preferably made of at least one metal selected from platinum, iridium, and ruthenium, or an alloy thereof. Also, the catalyst layer for a fuel cell preferably further contains an ionomer, and the ratio of mass of the ionomer (I) to mass of the catalyst-supporting support (S), I/S, is preferably 0.06 or more and 0.23 or less.