LAYERED PLATINATE, LAYERED PLATINIC ACID, PLATINIC ACID NANOSHEET, PLATINUM NANOSHEET, AND MANUFACTURING METHOD THEREOF

To provide a layered platinate, a layered platinic acid, a platinic acid nanosheet, a platinum nanosheet, and a manufacturing method of the platinum nanosheet that are used for fabricating a platinum nanosheet usable as an electrocatalyst for fuel cells, a catalyst for purifying exhaust gas, a catalyst for synthesizing chemical products, and the like. The above-described problem is solved by a layered platinate comprising MPtO·nHO (where M is a monovalent metal), the MPtO·nHO being layered (the M being potassium and diffraction peaks are at 2θ diffraction angles of 13° and 26°); a layered platinic acid comprising HPtO·nHO, the HPtO·nHO being layered; a platinic acid nanosheet having a thickness of 1 nm or less; and a platinum nanosheet having a thickness of 0.6 nm or less.