Oxidative etching and its role in manipulating the nucleation and growth of noble-metal nanocrystals

Oxidative etching plays an important role in the synthesis of metal nanocrystals. This is because the zerovalent species, including atoms, clusters, and nanocrystallites, can all be oxidized back to the ionic form and thus altering the types and distributions of products formed in both the nucleation and growth steps. In the first part of this review, we discuss the critical components needed for oxidative etching, as well as methods for enabling or preventing oxidative etching in a synthesis. We then present and analyze a number of interesting experimental observations caused by oxidative etching. In the following sections, we highlight four major applications of oxidative etching in the synthesis of metal nanocrystals, with regards to experimental controls over the crystallinity, size, shape, morphology, and growth kinetics.