Shape-Controlled Nanoparticles: Effect of Shape on Catalytic Activity, Selectivity, and Long-Term Stability

Abstract

Recently, various techniques have been developed for the synthesis of shaped nanoparticles. The utilization of organic surface-capping agents with an affinity for specific facets, the addition of inorganic shape-controlling agents (such as halide ions), controlling the reduction rate of the metal precursor, and the use of electrochemical methods have been reported as strategies to control the shape of metal and metal oxide nanoparticles. These nanoparticles often have well-defined facets with predetermined atomic arrangements and these distinct surface structures influence the catalytic properties of the nanoparticles. Examples showing the effect of shape on the enhancement of activity, selectivity, and long-term stability are reviewed in this chapter. Catalytic property testing has shown that the method for the removal of the organic surface-capping agent is important. The shape often undergoes degradation during the removal process or during the catalytic reaction. A way to synthesize shaped nanoparticles without surface-capping agents is introduced. A few examples where organic layers have positive effects on catalytic reactions are also shown. Finally, issues that remain to be resolved to allow for practical application of the shaped nanoparticles are addressed.