A composite electrode includes two or more types of fibers forming a fiber network, comprising at least a first type of fibers and a second type of fibers. The first type of fibers comprises a first polymer and a first type of particles. The second type of fibers comprises a second polymer and a second type of particles. The second polymer is same as or different from the first polymer. The second type of particles are same as or different from the first type of particles.

Nanoporous oxygen reduction catalyst material comprising PtNiAu. The nanoporous oxygen reduction catalyst material is useful, for example, in fuel cell membrane electrode assemblies.

A method for preparing a platinum-indium cluster catalyst for a fuel cell, the method including steps of: obtaining a carbon powder, dispersing the carbon powder in a strong oxidizing solution, and performing high-temperature hydrothermal treatment to obtain an activated carbon powder; obtaining a mixed alcohol solution comprising a platinum precursor and an indium precursor; dispersing the activated carbon powder in the mixed alcohol solution, and heat treating the mixed alcohol solution to volatilize an alcohol solvent to obtain a mixed powder; and performing high-temperature treatment on the mixed powder under a mixed gas atmosphere of hydrogen and argon, to yield a platinum-indium cluster catalyst for a fuel cell.

A Pd—Ru alloy catalyst for hydrogen production and its preparation methods are provided. The catalyst can include a plurality of particles comprising an alloy of at least palladium (Pd) and ruthenium (Ru). Moreover, the catalyst can further include a support material such as carbon support having external or internal surfaces on which the plurality of particles is dispersed. The alloy catalyst can have a molar ratio of Pd:Ru in a range of about 0.5:1 to about 9:1. For hydrogen evolution reaction (HER), the Pd—Ru alloy catalyst exhibits increased catalytic activities comparing to some well-known catalysts.

A water electrolysis catalyst containing a solid solution complex oxide of Ir and Ru, in which the solid solution complex oxide is represented by a chemical formula Ir.sub.xRu.sub.yO.sub.2 (where x and y satisfy x+y=1.0); and the solid solution complex oxide has one diffraction maximum peak in a range of 2θ=66.10° or more and 67.00° or less in powder X-ray diffraction (Cu Kα).

A catalyst for a fuel cell includes: a crystalline carbon support having a specific surface area of about 200 m.sup.2/g to about 500 m.sup.2/g; and intermetallic active particles of a transition metal and a noble metal, wherein the intermetallic active particles are supported on the crystalline carbon support and have a particle diameter of greater than or equal to about 3 nm.

Provided is a method of preparing an intermetallic catalyst which includes applying ultrasonic wave to a precursor mixture solution including a noble metal precursor, a transition metal precursor, and a carbon support having an average pore size of about 6 nm to about 15 nm and a specific surface area of about 200 m.sup.2/g to about 2000 m.sup.2/g to form alloy particles in pores of the carbon support, and annealing the alloy particles in the pores of the carbon support to form intermetallic alloy particles.

An electrode for a redox flow battery through which an electrolyte is circulated includes a porous body, and reactive particles that contribute to a battery reaction. The reactive particles are pressed against the porous body by a flow of the electrolyte without being immobilized on the porous body.

Compositions comprised of a tin film, coated by a shell of less than 50 nm thick made of palladium and tin in a molar ratio ranging from 1:4 to 3:1, respectively, are disclosed. Uses of the compositions as an electro-catalyst e.g., in a fuel cell, and particularly for the oxidation of various materials are also disclosed.

The present invention provides a process for preparing a catalyst precursor, said process comprising the steps of (i) providing Pt.sub.aX.sub.b alloy particles on a support material and (ii) applying a shell of X to the Pt.sub.aX.sub.b alloy particles to provide a catalyst precursor comprising particles having a Pt.sub.aX.sub.b core and an X shell. The ratio of a to b is in the range of and including 10:1 to 1:2.5 and X is Co, Ni, Y, Gd, Sc or Cu. Also provided is a process for preparing a catalyst material.