# US 2006/0134505 A1 · Hydrogen absorption induced metal deposition on palladium and palladium-alloy particles > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2006/0134505 A1 - Document ID: US20060134505A1 - Status: Published application - Kind: A1 - Application number: 11/019,734 - Filed: 2004-12-22 - Published: 2006-06-22 - Earliest claimed: 2004-12-22 - Assignees: Brookhaven Science Associates, LLC - Inventors: Jia Wang; Radoslav Adzic - Web page: https://patentgrep.com/patent/US20060134505A1 ## CPC - H01M 4/8657: {layered} - B22F 1/17: Metallic particles coated with metal - B22F 1/18: Non-metallic particles coated with metal - H01M 4/92: Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence) - H01M 4/921: {Alloys or mixtures with metallic elements} - H01M 4/926: {on carbon or graphite} - B22F 2998/00: Supplementary information concerning processes or compositions relating to powder metallurgy - B22F 2999/00: Aspects linked to processes or compositions used in powder metallurgy - H01M 4/0497: {Chemical precipitation} - Y02E 60/10: Energy storage using batteries - Y02E 60/50: Fuel cells - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - B22F: WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER (making alloys by powder metallurgy C22C); APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract The present invention relates to methods for producing metal-coated palladium or palladium-alloy particles. The method includes contacting hydrogen-absorbed palladium or palladium-alloy particles with one or more metal salts to produce a sub-monoatomic or monoatomic metal- or metal-alloy coating on the surface of the hydrogen-absorbed palladium or palladium-alloy particles. The invention also relates to methods for producing catalysts and methods for producing electrical energy using the metal-coated palladium or palladium-alloy particles of the present invention. ## Claims ### Claim 1 A method for producing metal-coated palladium or palladium-alloy particles, the method comprising contacting hydrogen-absorbed palladium or palladium-alloy particles with a metal salt or metal salt mixture to deposit a sub-monoatomic or monoatomic metal coating or sub-monoatomic or monoatomic metal alloy coating on the surface of said hydrogen-absorbed palladium or palladium-alloy particles, thereby producing metal-coated or metal alloy-coated palladium or palladium-alloy particles. ### Claim 2 (depends on 1) A method according to claim 1, wherein said metal salt or metal salt mixture is dissolved in a liquid phase. ### Claim 3 (depends on 2) A method according to claim 2, wherein said metal salt or metal salt mixture is in the form of an aqueous solution of said metal salt or metal salt mixture. ### Claim 4 (depends on 1) A method according to claim 1, wherein said metal-coated palladium or palladium-alloy particles are metal-coated palladium or palladium-alloy nanoparticles. ### Claim 5 (depends on 4) A method according to claim 4, wherein said metal-coated palladium or palladium-alloy nanoparticles are from about 3 nanometers to about 500 nanometers in size. ### Claim 6 (depends on 5) A method according to claim 5, wherein said metal-coated palladium or palladium-alloy nanoparticles are from about 5 nanometers to about 10 nanometers in size. ### Claim 7 (depends on 1) A method according to claim 1, wherein said metal-coated palladium or palladium-alloy particles are metal-coated palladium or palladium-alloy microparticles. ### Claim 8 (depends on 7) A method according to claim 7, wherein said metal-coated palladium or palladium-alloy microparticles are from about 500 nanometers to about 10 microns in size. ### Claim 9 (depends on 1) A method according to claim 1, wherein a single metal salt is used to deposit a sub-monoatomic or monoatomic metal coating. ### Claim 10 (depends on 9) A method according to claim 9, wherein the metal in said metal salt and said sub-monoatomic or monoatomic metal coating is a transition metal. ### Claim 11 (depends on 10) A method according to claim 10 wherein the transition metal is platinum. ### Claim 12 A method for producing metal-coated palladium particles, the method comprising contacting hydrogen-absorbed palladium particles with a metal salt or metal salt mixture to deposit a sub-monoatomic or monoatomic metal coating or sub-monoatomic or monoatomic metal alloy coating on the surface of said hydrogen-absorbed palladium particles, thereby producing metal-coated or metal alloy-coated palladium particles. ### Claim 13 A method for producing metal-coated palladium-alloy particles, the method comprising contacting hydrogen-absorbed palladium-alloy particles with a metal salt or metal salt mixture to deposit a sub-monoatomic or monoatomic metal coating or sub-monoatomic or monoatomic metal alloy coating on the surface of said palladium-alloy particles, thereby producing metal-coated or metal alloy-coated palladium-alloy particles. ### Claim 14 (depends on 13) A method-according to claim 13, wherein the palladium-alloy in said metal-coated palladium alloy particles is comprised of a homogeneous combination of palladium and one or more alloying metals. ### Claim 15 (depends on 14) A method according to claim 14, wherein the palladium-alloy in said metal-coated palladium alloy particles is comprised of a homogeneous phase of palladium and an alloying metal. ### Claim 16 (depends on 15) A method according to claim 15, wherein said alloying metal is a transition metal. ### Claim 17 (depends on 16) A method according to claim 16, wherein the transition metal is a 3d transition metal. ### Claim 18 (depends on 16) A method according to claim 16, wherein the 3d transition metal is nickel, cobalt, iron, gold, or a combination thereof. ### Claim 19 (depends on 13) A method according to claim 13, wherein the palladium-alloy in said metal-coated palladium alloy particles is comprised of a heterogeneous phase of palladium and one or more alloying metals, provided that some component of palladium in said palladium-alloy is bonded to the sub-monoatomic or monoatomic metal or metal alloy coating. ### Claim 20 (depends on 19) A method according to claim 19, wherein said heterogeneous phase is comprised of an inner core of one or more alloying metals coated with an outer shell of palladium. ### Claim 21 (depends on 1) A method according to claim 1, further comprising bonding said metal-coated palladium or palladium alloy particles to a support. ### Claim 22 (depends on 21) A method according to claim 21, wherein the support is electrically conductive. ### Claim 23 (depends on 22) A method according to claim 22, wherein the support is carbon black, graphitized carbon, graphite, or activated carbon. ### Claim 24 (depends on 1) A method according to claim 1 further comprising metal-bonding ligands or surfactants on the surface of said metal-coated palladium or palladium-alloy particles. ### Claim 25 A method for producing electrical energy, the method comprising: (i) contacting an oxygen-reducing cathode of a fuel cell with oxygen, wherein the oxygen-reducing cathode is comprised of platinum-coated or platinum alloy-coated palladium or palladium-alloy particles bound to an electrically conductive support; wherein said platinum-coated or platinum alloy-coated palladium or palladium-alloy particles are produced by a method comprising: contacting hydrogen-absorbed palladium or palladium-alloy particles with a platinum salt, or a mixture of a platinum salt and one or more non-platinum metal salts, to deposit a sub-monoatomic or monoatomic platinum coating or sub-monoatomic or monoatomic platinum alloy coating on the surface of said palladium or palladium-alloy particles, thereby producing platinum-coated or platinum alloy-coated palladium or palladium-alloy particles; and (ii) contacting an anode of said fuel cell with a fuel source; wherein said oxygen-reducing cathode is in electrical contact with said anode; and said oxygen-reducing cathode and said anode are in chemical contact through mutual contact with a proton-conducting medium. ### Claim 26 (depends on 25) A method according to claim 25, wherein said platinum-coated or platinum alloy-coated palladium or palladium-alloy particles are platinum-coated or platinum alloy-coated palladium or palladium-alloy nanoparticles. ### Claim 27 (depends on 26) A method according to claim 26, wherein said platinum-coated or platinum alloy-coated palladium or palladium-alloy nanoparticles have a size of from about 5 nanometers to about 10 nanometers. ### Claim 28 (depends on 27) A method according to claim 27, wherein the fuel source is hydrogen. ### Claim 29 (depends on 27) A method according to claim 27, wherein the fuel source is an alcohol. ### Claim 30 (depends on 29) A method according to claim 29, wherein the alcohol is methanol. ### Claim 31 (depends on 27) A method according to claim 27, wherein the fuel source is gasoline reformate. ### Claim 32 (depends on 1) A method according to claim 1, wherein said hydrogen-absorbed palladium or palladium-alloy particles are formed by exposing palladium or palladium-alloy substrate particles to hydrogen. ### Claim 33 (depends on 32) A method according to claim 32, wherein said palladium or palladium-alloy substrate particles are not in contact with the metal salt or metal salt mixture when the palladium or palladium-alloy substrate particles are exposed to hydrogen. ### Claim 34 (depends on 33) A method according to claim 33, wherein said palladium or palladium-alloy substrate particles and said hydrogen-absorbed palladium or palladium-alloy particles are bound to a support. ### Claim 35 (depends on 32) A method according to claim 32, wherein the palladium or palladium-alloy substrate particles are in contact with the metal salt or metal salt mixture when the palladium or palladium-alloy substrate particles are exposed to hydrogen. ### Claim 36 (depends on 33) A method according to claim 33, further comprising additional exposure to hydrogen after the metal salt or metal salt mixture contacts the hydrogen-absorbed palladium or palladium-alloy particles. ### Claim 37 (depends on 32) A method according to claim 32, wherein the palladium or palladium-alloy particles are exposed to hydrogen for a period of time sufficient to bring x in PdHx to a value of approximately 0.6.