The present invention relates to catalysts or catalytic systems comprising liquid metals, and in particular, to catalysts or catalytic systems comprising liquid metals droplets dispersed in a solvent, as well as to methods and uses of such catalysts or catalytic systems. In some embodiments, the present disclosure provides a ‘green’ carbon capture and conversion technology offering scalability and economic viability for mitigating CO.sub.2 emissions.

A perovskite-type composite oxide powder is a perovskite-type composite oxide powder represented by a general formula ABO.sub.3-δ (where δ represents an amount of deficiency of oxygen and 0≤δ<1), an element contained in an A site is La, elements contained in a B site are Co and Ni and a crystallite size determined by a Williamson-Hall method is equal to or greater than 20 nm and equal to or less than 100 nm. In this way, when the perovskite-type composite oxide powder is used as an air electrode material for a fuel cell, an air electrode in which the resistance thereof is low and the conductivity thereof is high can be obtained.

A bifunctional catalyst and a preparation method therefor are provided. The bifunctional catalyst is prepared by providing carbon matrix, adding 0.01-10 mol/L platinum containing solution, 0.01-10 mol/L palladium containing solution, 0.01-10 mol/L silver containing solution, and 0.01-15 mol/L sodium citrate trihydrate solution to the carbon matrix for reacting at 20° C. to 80° C. for 0.5 h to 24 h to obtain a mixed solution, and adding reducing agent to the mixed solution for reacting for 0.5 h to 30 h, and centrifuging and drying so as to obtain the bifunctional catalyst.

An oxygen reduction catalyst for use in low-temperature fuel cells and a method for the production thereof. This is in particular carrier-free and free from precious metals. It is based on a conductive polymer produced from a nitrogenous aromatic monomer, which leads to conductive polymers, and an aromatic sulfonic acid, which polymer is pyrolyzed together with one or more transition metal salts and is subsequently acid etched. In one particularly advantageous configuration variant, this involves a polypyrrole produced with sulfanilic acid as a doping agent.

Provided is a catalyst layer for gas diffusion electrode that can be used without using carbon supports, a method for manufacturing the same, a membrane electrode assembly, and a fuel cell. The catalyst layer for gas diffusion electrode according to the present invention includes a network-like metallic catalyst formed of a sintered body, the network-like metallic catalyst including nanoparticles linked with each other to have electron conductivity; and an ion conductor, at least a part of the ion conductor contacting the network-like metallic catalyst. Further, the membrane electrode assembly according to the present invention includes a polymer electrolyte membrane provided between an anode catalyst layer and a cathode catalyst layer, and the catalyst layer for gas diffusion electrode stated above is used in at least one of the anode catalyst layer and the cathode catalyst layer.

A process for producing an oxygen reducing catalyst including a step of heat-treating, in a non-oxidizing atmosphere, a catalyst precursor including a compound (i) supplying a carbon element and a nitrogen element by heating in a non-oxidizing atmosphere, and a compound (ii) containing at least one element of iron and cobalt. Also disclosed is an oxygen reducing catalyst, a fuel cell catalyst layer including the oxygen reducing catalyst, an electrode including the fuel cell catalyst layer, a membrane-electrode assembly including the electrode and a fuel cell including the membrane-electrode assembly.

A composite for a lithium air battery, wherein the composite is represented by Formula 1:
MC.sub.xN.sub.(1−x)  Formula 1 wherein M in Formula 1 is at least one selected from a metal element and a metalloid element, and 0<x<1.

A hydrogen/bromine reduction-oxidation flow battery system includes a bromine electrode, a hydrogen electrode, a membrane, a first catalyst, and a second catalyst. The membrane is positioned between the bromine electrode and the hydrogen electrode. The first catalyst is associated with the bromine electrode. The second catalyst is associated with the hydrogen electrode and at least partially formed from a subsurface alloy configured (i) to promote facile dissociation of H.sub.2, and (ii) to prevent bromide from adsorbing onto the hydrogen electrode.

Electrodes employing as active material metal nanoparticles synthesized by a novel route are provided. The nanoparticle synthesis is facile and reproducible, and provides metal nanoparticles of very small dimension and high purity for a wide range of metals. The electrodes utilizing these nanoparticles thus may have superior capability. Electrochemical cells employing said electrodes are also provided.

Provided are a carbon catalyst, an electrode, and a battery that exhibit excellent activity. A carbon catalyst according to one embodiment of the present invention has a carbon structure in which area ratios of three peaks f.sub.broad, f.sub.middle, and f.sub.narrow obtained by separating a peak in the vicinity of a diffraction angle of 26° in an X-ray diffraction pattern obtained by powder X-ray diffraction satisfy the following conditions (a) to (c): (a) f.sub.broad: 75% or more and 96% or less; (b) f.sub.middle: 3.2% or more and 15% or less; and (c) f.sub.narrow: 0.4% or more and 15% or less.