Engineering Nanoscale Interfaces of Metal/Oxide Nanowires to Control Catalytic Activity

Abstract

The interfacial effect between a metal catalyst and its various supporting transition metal oxides on the catalytic activity of heterogeneous catalysis has been extensively explored; engineering interfacial sites of metal supported on metal oxide has been found to influence catalytic performance. Here, we investigate the interfacial effect of Pt nanowires (NWs) vertically and alternatingly stacked with titanium dioxide (TiO 2 ) or cobalt monoxide (CoO) NWs, which exhibit a strong metal−support interaction under carbon monoxide (CO) oxidation. High-resolution nanotransfer printing based on nanoscale pattern replication and e-beam evaporation were utilized to obtain the Pt NWs cross-stacked on the CoO or TiO 2 NW on the silicon dioxide (SiO 2 ) substrate with varying numbers of nanowires. The morphology and interfacial area were precisely determined by means of atomic force microscopy and scanning electron microscopy. The cross-stacked Pt/ TiO 2 NW and Pt/CoO NW catalysts were estimated with CO oxidation under 40 Torr CO and 100 Torr O 2 from 200 to 240 °C. Higher catalytic activity was found on the Pt/CoO NW catalyst than on Pt/TiO 2 NWs and Pt NWs, which indicates the significance of nanoscale metal−oxide interfaces. As the number of nanowire layers increased, the catalytic activity became saturated. Our study demonstrates the interfacial role of nanoscale metal−oxide interfaces under CO oxidation, which has intriguing applications in the smart design of catalytic materials.

Noble Metal Nanoparticles Decorated Metal Oxide Semiconducting Nanowire Arrays Interwoven into 3D Mesoporous Superstructures for Low-Temperature Gas Sensing

“…More recently, great efforts have been devoted to enhancing the crystallization degree of mesoporous semiconductor metal oxides while maintaining their highly porous structure by using 1D nanowires as the building blocks due to their good mechanical properties and direct electronic pathways. However, the disordered stacking of nanowires by conventional methods can reduce their exposed active sites and limit their performances. − Although different methods such as the Langmuir–Blodgett (LB) technique and nanotransfer printing have been applied to construct 3D nanostructures assembled from 1D nanowires, they required tedious multistep process and failed to produce metal oxide-based 3D mesoporous nanostructures. − In the previous work, our group reported an interesting synthetic 3D mesoporous nanostructure consisting of multilayer cross-stacked nanowire arrays of Si-doped WO 3 through the coassembly of amphiphilic block copolymers (BCPs) and silicotungstic acid. Different from a typical surfactant-directed sol–gel process in conventional synthesis, the current synthesis involves an unusual self-assembly of organic–inorganic hybrid micelles, resulting in novel topological mesoporous structures, namely, 3D orthogonally cross-stacked nanowire arrays.…”

Block Copolymer Nanopatterning for Nonsemiconductor Device Applications

“…In addition, taking advantage of the diverse choices in the deposition materials, a heterogeneous catalyst system can be introduced from two or more choices. In summary, by a synergistic combination of BCP nanopatterning with transfer printing method, on-demand designed catalyst systems can be architectured by varying the pattern density and catalyst materials. , …”

“…In summary, by a synergistic combination of BCP nanopatterning with transfer printing method, on-demand designed catalyst systems can be architectured by varying the pattern density and catalyst materials. 86,87 Bicontinuous 3D structures, such as gyroid and doublediamond (DD) structures, are promising materials for catalysts, because of their large specific surface area and uniform pore size throughout the film. 88,89 Moreover, the bicontinuous structure can contain large amounts of electrolytes and reactants that easily penetrate the inner space.…”

Microwave‐Positioning Assembly: Structure and Surface Optimizations for Catalysts

“…Interface modification is an effective way to achieve high stability and efficient carrier transport of composite materials. Changing the interface coupling mode, [ 112–115 ] enhancing the interfacial force, [ 116–118 ] and increasing the effective sites of the interface [ 119,120 ] are all feasible approaches in the process of physical or chemical synthesis of materials to modify the interface.…”