# US 2014/0193746 A1 · Cost-effective core-shell catalyst with high electrochemical stability > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0193746 A1 - Document ID: US20140193746A1 - Status: Published application - Kind: A1 - Application number: 14/112,373 - Filed: 2011-07-25 - Published: 2014-07-10 - Earliest claimed: 2011-07-25 - Assignees: Toyota Motor Europe; Ilika Technologies Limited - Inventors: Isotta Cerri; Tetsuo Nagami; Brian Elliott Hayden; Jonathan Conrad Davies - Web page: https://patentgrep.com/patent/US20140193746A1 ## CPC - H01M 4/8657: {layered} - B01J 21/06: Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof - B01J 23/42: Platinum - B01J 23/6484: {Niobium} - B01J 35/397: {Egg shell like} - B01J 37/0221: {of particles} - H01M 4/9016: {Oxides, hydroxides or oxygenated metallic salts} - H01M 4/92: Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence) - H01M 4/921: {Alloys or mixtures with metallic elements} - H01M 2008/1095: {Fuel cells with polymeric electrolytes} - Y02E 60/50: Fuel cells - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract The present invention concerns a core-shell composite material comprising: a core consisting of Nb-doped TiO2 of formula TiNbOx; and a shell consisting of a homogeneous layer of Pt or Pt alloy of 1 to 50 ML in thickness. The core-shell composite material may in particular find application in fuel cells. ## Claims ### Claim 1 A core-shell composite material comprising: a core consisting of Nb-doped TiO2 of formula TiNbOx; and a shell consisting of a homogeneous layer of Pt or Pt alloy of 1 to 50 ML in thickness. ### Claim 2 (depends on 1) A core-shell composite material according to claim 1, wherein the TiNbOx core, prior to laying down of the Pt or Pt alloy shell, has been subjected to a process to reduce the surface of the TiNbOx core, ### Claim 3 (depends on 2) A core-shell composite material according to claim 2, wherein the process to reduce the surface of the TiNbOx core comprises annealing in ultra high vacuum, at a pressure lower than 10−9 Torr, at a temperature of 600 to 1000° C., for a duration of 5 minutes to 1 hour. ### Claim 4 (depends on 2) A core-shell composite material according to claim 2, wherein the process to reduce the surface of the TiNbOx core comprises in treatment in a hydrogen atmosphere of 10−5 to 10−7 Torr H2, at a temperature of 600 to 1000° C., for a duration of 5 minutes to 1 hour. ### Claim 5 (depends on 1) A core-shell composite material according to claim 1, wherein the amount of Nb in the TiNbOx core is at most 25 at % on a metal basis, excluding the oxygen content. ### Claim 6 (depends on 5) A core-shell composite material according to claim 5, wherein the amount of Nb in the TiNbOx core is at least 1 at % and at most 15 at % on a metal basis, excluding the oxygen content. ### Claim 7 (depends on 1) A core-shell composite material according to claim 1, wherein the TiNbOx is in the rutile phase. ### Claim 8 (depends on 1) A core-shell composite material according to claim 1, wherein the thickness of the Pt or Pt alloy shell is of at least 2 ML and at most 20 ML. ### Claim 9 (depends on 8) A core-shell composite material according to claim 8, wherein the thickness of the Pt or Pt alloy shell is of at least 2 ML and at most 5 ML. ### Claim 10 (depends on 1) A core-shell composite material according claim 1, wherein the material is in the form of a thin film with a planar underlying Nb-doped TiO2 layer and a planar overlying Pt or Pt alloy layer. ### Claim 11 (depends on 10) A core-shell composite material in the form of a thin film according to claim 10, wherein the TiNbOx core layer thickness is at least 5 nm and at most 1000 nm. ### Claim 12 (depends on 11) A core-shell composite material in the form of a thin film according to claim 11, wherein the TiNbOx core layer thickness is at least 5 nm and at most 200 nm. ### Claim 13 (depends on 11) A core-shell composite material in the form of a thin film according to claim 11, wherein the TiNbOx core layer thickness is at least 5 nm and at most 100 nm. ### Claim 14 (depends on 1) A core-shell composite material according claim 1, wherein the material is in the form of a particle, wherein the core is an Nb-doped TiO2 nanoparticle having a particle diameter of at least 2 nm and at most 500 nm, and the shell, deposited on the surface of the Nb-doped TiO2 nanoparticle core, is a Pt or Pt alloy, ### Claim 15 (depends on 14) A core-shell composite material according to claim 14, wherein the core is an Nb-doped TiO2 nanoparticle having a particle diameter of at least 2 nm and at most at most 100 nm. ### Claim 16 (depends on 15) A core-shell composite material according to claim 15, wherein the core is an Nb-doped TiO2 nanoparticle having a particle diameter of at least 2 nm and at most at most 50 nm. ### Claim 17 Process for the preparation of a core-shell composite material comprising the steps of: (1) preparation of a TiNbOx core, which may be in the form of a thin film or a (nano)particle; (2) chemical reduction of the surface of the TiNbOx core; (3) deposit of a homogeneous layer of platinum or platinum alloy on the reduced surface of the TiNbOx core obtained in step (2). ### Claim 18 (depends on 17) Process according to claim 17, wherein the process to reduce the surface of the TiNbOx core comprises annealing in ultra high vacuum, at a pressure lower than 10−9 Torr, at a temperature of 600 to 1000° C., for a duration of 5 minutes to 1 hour. ### Claim 19 (depends on 17) Process according to claim 17, wherein the process to reduce the surface of the TiNbOx core comprises in treatment in a hydrogen atmosphere of 10−5 to 10−7 Torr H2, at a temperature of 600 to 1000° C., for a duration of 5 minutes to 1 hour. ### Claim 20 (depends on 17) Process according to claim 17, wherein the TiNbOx core is prepared in the rutile phase. ### Claim 21 (depends on 17) Process according to claim 17, wherein the amount of Nb in the TiNbOx core is at most 25 at % on a metal basis, excluding the oxygen content. ### Claim 22 (depends on 17) Process according to claim 17, wherein the thickness of the Pt or Pt alloy shell is of at least 2 ML and at most 20 ML.