Cathodic Corrosion: A Quick, Clean, and Versatile Method for the Synthesis of Metallic Nanoparticles

摘要

In many important chemical reactions metals are used as catalysts. As only the surface of these, often very expensive, catalysts is involved in the reaction, it is beneficial to maximize the surface-to-volume ratio by decomposing the metal in small nanoparticles. Mechanical means have proven inadequate, and therefore the development of methods for chemical synthesis of metal nanoparticles has been an extremely active area of research for the last 30 years. Remarkable advances have been achieved in the preparation of highly dispersed, homogeneously small nanoparticles by the development of less complicated procedures. At the basis of all known synthetic methods lies the reduction reaction of metal cations. To limit the number of reduced cations per nanoparticle and keep its size as constant as possible, extra chemical stabilizers are invariably added. Stabilizers contaminate the final product and adversely affect its performance, for example, in catalysis and biological applications. Here, we report a radically different, simple, and counterintuitive method of nanoparticle synthesis, opening a new direction towards producing nanomaterials with improved functional properties. The method is based on extreme cathodic polarization of a metal, leading to the formation of cation-stabilized metal anions, which then act as precursors to the formation of nanoparticles.