A Rational Repeating Template Method for Synthesis of 2 D Hexagonally Ordered Mesoporous Precious Metals

Abstract

A repeating template method is presented for the synthesis of mesoporous metals with 2D hexagonal mesostructures. First, a silica replica (i.e., silica nanorods arranged periodically) is prepared by using 2D hexagonally ordered mesoporous carbon as the template. After that, the obtained silica replica is used as the second template for the preparation of mesoporous ruthenium. After the ruthenium species are introduced into the silica replica, the ruthenium species are then reduced by a vapor-infiltration method by using the reducing agent dimethylamine borane. After the ruthenium deposition, the silica is chemically removed. Analysis by transmission and scanning electron microscopies, a nitrogen-adsorption-desorption isotherm, and small-angle X-ray scattering revealed that the mesoporous ruthenium had a 2D hexagonal mesostructure, although the mesostructural ordering is decreased compared to that of the original mesoporous carbon template. This method is widely applicable to other metal systems. By changing the metal species introduced into the silica replica, several mesoporous metals (palladium and platinum) can be synthesized. Ordered mesoporous ruthenium and palladium, which are not easily attainable by the soft-templating methods, can be prepared. This study has overcome the composition variation limitations of the soft-templating method.

Synthesis of copper micro-rods with layered nano-structure by thermal decomposition of the coordination complex Cu(BTA)2

“…Among the periodic table of elements, metals of silver, nickel, copper, palladium, ruthenium, titanium, and platinum have been intensively investigated for their porous foam. For example, Walsh et al used dextran as a sacrificial template to fabricate silver sponges, Yamauchi and coworkers prepared mesoporous nickel by an electroless deposition method in the presence of lyotropic liquid crystals, and Kuroda et al reported 2D hexagonally ordered mesoporous metals (Ru, Pt, or Pd) by dissolving silica replica [9][10][11]. In addition to these methods, the combustion technology is a general method to synthesize various porous metals and oxides [12][13][14].…”

Synthesis of copper micro-rods with layered nano-structure by thermal decomposition of the coordination complex Cu(BTA)2

“…Among the periodic table of elements, metals of silver, nickel, copper, palladium, ruthenium, titanium, and platinum have been intensively investigated for their porous foam. For example, Walsh et al used dextran as a sacrificial template to fabricate silver sponges, Yamauchi and co-workers prepared mesoporous nickel by an electroless deposition method in the presence of lyotropic liquid crystals, and Kuroda et al reported 2D hexagonally ordered mesoporous metals (Ru, Pt, or Pd) by dissolving silica replica [ 9 - 11 ]. In addition to these methods, the combustion technology is a general method to synthesize various porous metals and oxides [ 12 - 14 ].…”