Templated synthesis of pure and bimetallic gold/platinum nanotubes using complementary seeding and plating reactions

Abstract

The application of electroless plating to porous template membranes displays an important route towards one-dimensional metal nanostructures such as nanotubes. For this reaction class, activation pretreatments are required to introduce catalyst seeds, which initiate surface-selective metal deposition from the metastable plating baths. Hitherto, these pretreatments are performed as a means to an end to ensure reliable metal film nucleation, and introduce often undesired contaminations. In this work, we demonstrate that the seeding step can be recognized as a synthetic tool to purposefully adjust the chemical composition of electrolessly plated nanomaterials. By consecutive application of several interfacial reactions (polymer swelling, reducing agent absorption, metal nanoparticle nucleation, autocatalytic metal deposition), we fabricate gold-platinum nanotubes of well-defined composition. Aside strictly monometallic gold and platinum nanotubes, bimetallic nanotubes are produced which consist of platinum nanoparticles embedded in gold walls. As shown in the electrooxidation of formic acid, the nanotube composition has a pronounced impact on the properties of the resulting materials and can be used to enhance the catalyst performance. The outlined strategy provides a versatile route towards sets of compositionally varying metal nanostructures and allows to examine and to exploit multi-element synergies.