Proton-conducting, fluorinated polymer grafted particles for use in the preparation of catalytic layers for fuel cells, such as H.sub.2/air cells or H.sub.2/O.sub.2 cells. The grafted particles include a particle made of a material for catalyzing oxygen reduction or hydrogen oxidation, such as a platinum particle, that has been grafted with a proton-conducting, fluorinated polymer graft. The proton-conducting, fluorinated polymer graft includes an organic spacer group, a single bond or an organic spacer group, a repeating unit resulting from polymerization of a fluorinated styrenic monomer, and a repeating unit resulting, from polymerization of a non-fluorinated styrenic monomer bearing at least one proton-conducting group.

A cathode, a membrane electrode assembly, and a battery, each has excellent durability. The cathode is a cathode of a battery including an electrolyte membrane, the cathode including: a first layer which contains 0.3 mg/cm.sup.2 or more and 9.0 mg/cm.sup.2 or less of a carbon catalyst; and a second layer which is arranged between the electrolyte membrane and the first layer in the battery, and which contains 0.002 mg/cm.sup.2 or more and 0.190 mg/cm.sup.2 or less of platinum.

An electrocatalytically active ink composition is used with an additive manufacturing process, such as 3D printing, to produce electrodes having consistent, adaptable, and high surface area structures. The electrocatalytically active ink composition includes a mixed powdered precursor and a polymer matrix. The mixed powdered precursor includes a carbon source, a dopant source, and/or a metal-containing catalyst. The material and electrochemical properties of the ink composition may facilitate 3D printing of electrochemically active electrodes for energy conversion and storage devices, and may allow fine-tuning of macro- and microstructures to develop electrodes having improved activity and efficiency.

Disclosed is a method for preparing a ternary alloy catalyst with polydopamine coating and a ternary alloy catalyst prepared thereby. The method for preparing a ternary alloy catalyst according to the present disclosure may provide a ternary alloy catalyst with increased resistance to carbon monoxide (CO) poisoning in which polydopamine is utilized as a coating material for a ternary alloy catalyst having a core-shell structure containing platinum to suppress the growth of particles during subsequent high-temperature heat treatment, and nickel (Ni), which is a transition metal, is diffused inside to form a core, thereby effectively preventing elution of nickel under an acidic condition.

The present invention relates to a catalyst for solid polymer fuel cells in which catalyst particles containing Pt as an essential catalyst metal are supported on a carbon powder carrier. The catalyst has good initial activity and good durability. When the catalyst is analyzed by X-ray photoelectron spectroscopy after potential holding at 1.2 V (vs. RHE) for 10 minutes in a perchloric acid solution, a ratio of zero-valent Pt to total Pt is 75% or more and 95% or less. The present inventive catalyst metal is preferably one obtained by alloying Pt with one of Co, Ni and Fe, and further with one of Mn, Ti, Zr and Sn. In addition, it is preferable that a fluorine compound having a C—F bond is supported on at least the surfaces of catalyst particles in an amount of 3 to 20 mass % based on the total mass of the catalyst.

Proposed is an iridium alloy catalyst having reversible catalytic activity for an oxygen evolution reaction (OER), a hydrogen evolution reaction (HER), and a hydrogen oxidation reaction (HOR) by including an iridium alloy including iridium (Ir) and nickel (Ni). The iridium alloy catalyst according to the present disclosure is rapidly converted to an iridium alloy catalyst in an oxide form and an iridium alloy catalyst in a metallic form according to applied voltage by controlling its crystallinity. Thus, even in case an oxide layer is formed after the OER, the oxidation layer disappears during the HER and HOR and the properties of an iridium metal catalyst remain, thereby maintaining HER/HOR performance.

An electrocatalyst material comprising: (i) a support material comprising a plurality of individual support particles or aggregates; (ii) first particles comprising a first metal and an alloying metal; and (iii) second particles consisting of a second metal or a second metal oxide, wherein the second metal is platinum or iridium; wherein each individual support particle or aggregate has dispersed thereon first particles and second particles, characterised in that the mean average particle size of the second particles is smaller than the mean average particle size of the first particles is disclosed. The electrocatalyst material has particular use in an electrode, such as the cathode, of an electrochemical cell, such as a fuel cell.

An anode can include: an electrode substrate; a first region of the substrate having a catalyst composition located thereon, wherein the catalyst composition includes an inorganic or metallic catalyst; and a second region of the substrate having an enzyme composition located thereon, wherein the combination of the catalyst composition and enzyme composition converts a fuel reagent to carbon dioxide at neutral pH. The first region and second region can be separate regions. The catalyst of the catalyst composition can include gold nanoparticles. The catalyst can include an inorganic or metallic catalyst selected from vanadium oxide, titanium (III) chloride, Pd(OAc).sub.2, MnO, zeolite, alumina, graphitic carbon, palladium, platinum, gold, ruthenium, rhodium, iridium, or combinations thereof. The catalyst can be nanoparticle, nanorod, nanodot, or combination thereof. The catalyst can have sizes that range from about 10 to 20 nm.

Compositions and process for optimizing oxygen reduction and oxygen evolution reactions are provided. Oxygen reduction and oxygen evolution catalysts include oxide compositions having a general formula a formula A.sub.2-xMO.sub.y, where x is electrochemically tuned to find optimal A content that delivers the best catalytic performance in a chemical system. The process provides the ability to find the optimal catalytic performance by tuning A and hence, the binding strength of O.

A catalyst system comprises an electrically conductive carrier metal oxide and an electrically conductive, metal oxide catalyst material, wherein the carrier metal oxide and the catalyst material differ in their composition and wherein the catalyst material and the carrier metal oxide are each stabilized with fluorine. A near-surface pH value, designated pzzp value (pzzp=point of zero zeta potential), of the carrier metal oxide and of the catalyst material differ from one another, wherein the pzzp value of either the carrier metal oxide or the catalyst material is at most pH=5. The catalyst material and the carrier metal oxide form an at least two-phase disperse oxide composite. The catalysts system may be used in an electrode which may be used in a fuel cell or an electrolyzer.