Designed Patterning of Mesoporous Metal Films Based on Electrochemical Micelle Assembly Combined with Lithographical Techniques.

Mesoporous noble metals and their patterning techniques for obtaining unique patterned structures are highly attractive for electrocatalysis, photocatalysis, and optoelectronics device applications owing to their expedient properties such as high level of exposed active locations, cascade electrocatalytic sites, and large surface area. However, patterning techniques for mesoporous substrates are still limited to metal oxide and silica films, although there is growing demand for developing techniques related to patterning mesoporous metals. In this study, the first demonstration of mesoporous metal films on patterned gold (Au) substrates, prefabricated using photolithographic techniques, is reported. First, different growth rates of mesoporous Au metal films on patterned Au substrates are demonstrated by varying deposition times and voltages. In addition, mesoporous Au films are also fabricated on various patterns of Au substrates including stripe and mesh lines. An alternative fabrication method using a photoresist insulating mask also yields growth of mesoporous Au within the patterning. Moreover, patterned mesoporous films of palladium (Pd) and palladium-copper alloy (PdCu) are demonstrated on the same types of substrates to show versatility of this method. Patterned mesoporous Au films (PMGFs) show higher electrochemically active surface area (ECSA) and higher sensitivity toward glucose oxidation than nonpatterned mesoporous Au films (NMGF).

Micelle-Assisted Strategy for the Direct Synthesis of Large-Sized Mesoporous Platinum Catalysts by Vapor Infiltration of a Reducing Agent.

Stable polymeric micelles have been demonstrated to serve as suitable templates for creating mesoporous metals. Herein, we report the utilization of a core-shell-corona type triblock copolymer of poly(styrene-b-2-vinylpyridine-b-ethylene oxide) and H2PtCl6·H2O to synthesize large-sized mesoporous Pt particles. After formation of micelles with metal ions, the reduction process has been carried out by vapor infiltration of a reducing agent, 4-(Dimethylamino)benzaldehyde. Following the removal of the pore-directing agent under the optimized temperature, mesoporous Pt particles with an average pore size of 15 nm and surface area of 12.6 m²·g-1 are achieved. More importantly, the resulting mesoporous Pt particles exhibit superior electrocatalytic activity compared to commercially available Pt black.