# US 2019/0314804 A1 · Solution-based approach to make porous coatings for sinter-resistant catalysts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0314804 A1 - Document ID: US20190314804A1 - Status: Published application - Kind: A1 - Application number: 16/454,709 - Filed: 2019-06-27 - Published: 2019-10-17 - Earliest claimed: 2017-01-05 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Xingcheng XIAO; Gongshin QI; Ryan J. DAY; Ming YANG - Web page: https://patentgrep.com/patent/US20190314804A1 ## CPC - B01J 37/035: {Precipitation on carriers} - B01J 23/42: Platinum - B01J 23/44: Palladium - B01J 35/398: {Egg yolk like} - B01J 35/45: Nanoparticles - B01J 37/08: Heat treatment {(B01J37/0009, B01J37/0018 take precedence)} - B01J 37/18: with gases containing free hydrogen - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS ## Abstract Catalyst systems that are resistant to high-temperature sintering and methods for preparing such catalyst systems that are resistant to sintering at high temperatures are provided. Methods of forming such catalyst systems include contacting a support having a surface including a catalyst particle with a solution comprising a metal salt and having an acidic pH. The metal salt is precipitated onto the surface of the support. Next, the metal salt is calcined to selectively generate a porous coating of metal oxide on the surface of the support distributed around the catalyst particle. ## Claims ### Claim 1 A catalyst system comprising: a platinum group metal catalyst bound to a metal oxide support; and a crystalline coating of metal oxide nanoparticles selectively disposed on the metal oxide support, wherein the crystalline coating has a porosity of greater than about 20% to less than about 70% and covers greater than or equal to about 1.5% to less than or equal to about 80% of an exposed surface area of the metal oxide support. ### Claim 2 (depends on 1) The catalyst system according to claim 1, wherein the platinum group metal catalyst comprises a metal selected from the group consisting of: platinum (Pt), ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), gold (Au), and combinations thereof. ### Claim 3 (depends on 1) The catalyst system according to claim 1, wherein the metal oxide nanoparticles comprise an element selected from the group consisting of: aluminum (Al), cerium (Ce), zirconium (Zr), titanium (Ti), silicon (Si), magnesium (Mg), zinc (Zn), sodium (Na), potassium (K), barium (Ba), calcium (Ca), and combinations thereof. ### Claim 4 (depends on 1) The catalyst system according to claim 1, wherein the metal oxide nanoparticles comprise a metal oxide selected from the group consisting of: aluminum oxide (Al2O3), cerium oxide (CeO2), zirconium oxide (ZrO2), titanium dioxide (TiO2), silicon dioxide (SiO2), magnesium oxide (MgO), zinc oxide (ZnO), barium oxide (BaO), potassium oxide (K2O), sodium oxide (Na2O), calcium oxide (CaO), and combinations thereof. ### Claim 5 (depends on 1) The catalyst system according to claim 1, wherein the metal oxide support comprises a metal oxide selected from the group consisting of: cerium oxide (CeO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), titanium dioxide (TiO2), silicon dioxide (SiO2), magnesium oxide (MgO), zinc oxide (ZnO), barium oxide (BaO), potassium oxide (K2O), sodium oxide (Na2O), calcium oxide (CaO), lanthanum oxide (La2O3), and combinations thereof; and the metal oxide nanoparticles comprise aluminum oxide (Al2O3). ### Claim 6 (depends on 1) The catalyst system according to claim 1, wherein the metal oxide support comprises aluminum oxide (Al2O3) and the metal oxide nanoparticles comprise aluminum oxide (Al2O3). ### Claim 7 (depends on 1) The catalyst system according to claim 1, wherein a loading density of the platinum group metal catalyst on the metal oxide support is greater than or equal to about 0.25% (w/w) to less than or equal to about 20% (w/w). ### Claim 8 (depends on 1) The catalyst system according to claim 1, wherein the metal oxide support is a monolith structure or a particle. ### Claim 9 (depends on 1) The catalyst system according to claim 1, wherein the metal oxide nanoparticles have an average diameter of greater than or equal to about 0.5 nm to less than or equal to about 50 nm and the crystalline coating comprises pores having an average diameter of greater than or equal to about 0.5 nm to less than or equal to about 30 nm. ### Claim 10 A catalyst system comprising: a platinum group metal catalyst selected from the group consisting of: palladium, platinum, and combinations thereof bound to a metal oxide support; and a crystalline coating of metal oxide nanoparticles selectively disposed on the metal oxide support distributed around the platinum group metal catalyst, wherein the crystalline coating has a porosity of greater than about 20% to less than about 70% and covers greater than or equal to about 1.5% to less than or equal to about 80% of an exposed surface area of the metal oxide support. ### Claim 11 (depends on 10) The catalyst system according to claim 10, wherein the metal oxide nanoparticles comprise a metal oxide selected from the group consisting of: aluminum oxide (Al2O3), cerium oxide (CeO2), zirconium oxide (ZrO2), titanium dioxide (TiO2), silicon dioxide (SiO2), magnesium oxide (MgO), zinc oxide (ZnO), barium oxide (BaO), potassium oxide (K2O), sodium oxide (Na2O), calcium oxide (CaO), and combinations thereof. ### Claim 12 (depends on 10) The catalyst system according to claim 10, wherein the metal oxide support comprises a metal oxide selected from the group consisting of: cerium oxide (CeO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), titanium dioxide (TiO2), silicon dioxide (SiO2), magnesium oxide (MgO), zinc oxide (ZnO), barium oxide (BaO), potassium oxide (K2O), sodium oxide (Na2O), calcium oxide (CaO), lanthanum oxide (La2O3), and combinations thereof; and the metal oxide nanoparticles comprise aluminum oxide (Al2O3). ### Claim 13 (depends on 10) The catalyst system according to claim 10, wherein the metal oxide support comprises aluminum oxide (Al2O3) and the metal oxide nanoparticles comprise aluminum oxide (Al2O3). ### Claim 14 (depends on 10) The catalyst system according to claim 10, wherein a loading density of the platinum group metal catalyst on the metal oxide support is greater than or equal to about 0.25% (w/w) to less than or equal to about 20% (w/w). ### Claim 15 (depends on 10) The catalyst system according to claim 10, wherein the metal oxide support is a monolith structure or a particle. ### Claim 16 (depends on 10) The catalyst system according to claim 10, wherein the metal oxide nanoparticles have an average diameter of greater than or equal to about 0.5 nm to less than or equal to about 50 nm and the crystalline coating comprises pores having an average diameter of greater than or equal to about 0.5 nm to less than or equal to about 30 nm. ### Claim 17 A catalyst system comprising: a platinum group metal catalyst selected from the group consisting of: palladium, platinum, and combinations thereof bound to a metal oxide support; and a crystalline coating of metal oxide nanoparticles that comprise aluminum oxide (Al2O3) selectively disposed on the metal oxide support comprising aluminum oxide (Al2O3), wherein the metal oxide nanoparticles have an average maximum diameter of greater than or equal to about 0.5 nm to less than or equal to about 50 nm and the crystalline coating has a porosity of greater than about 20% to less than about 70% and covers greater than or equal to about 1.5% to less than or equal to about 80% of an exposed surface area of the metal oxide support. ### Claim 18 (depends on 17) The catalyst system according to claim 17, wherein a loading density of the platinum group metal catalyst on the metal oxide support is greater than or equal to about 0.25% (w/w) to less than or equal to about 20% (w/w). ### Claim 19 (depends on 17) The catalyst system according to claim 17, wherein the metal oxide support is a monolith structure or a particle.