Fabrication of Paper-Templated Structures of Noble Metals

This manuscript describes a simple and rapid method for fabricating freestanding structures composed primarily (>94% w/w, and 55-80 at%) of noble metals (e.g., gold, silver, platinum, etc.) and having physical morphologies that resemble paper, thread, or fabric. In this method, templates (i.e., pieces of paper, or cotton fabric) are loaded with aqueous solutions of salts of noble metals, and then the cellulosic component is burned off in a furnace held at high temperatures (i.e., from 550 degrees C to 800 degrees C, depending on the procedure, in air). Even though the environment in a furnace is ostensibly oxidizing (e.g., hot air), the metal ions are reduced to elemental metal and form paper-templated or fabric-templated structures that have morphologies similar to that of the material from which they were derived (i.e., paper or fabric). Papertemplated structures are fibrous, permeable to gases and liquides, electrically conductive, and in some cases (e.g., paper-templated gold and papertemplated platinum structures), their surfaces are electroactive. The surface areas of paper-templated structures are more than 20 times higher than their projected areas. Paper-templated structures thus have properties that make them potentially useful in catalysis, sensing, and electroanalysis.