| Description |
Nanomaterials are the focus of intense research efforts in a variety of fields because of dramatic differences in properties when compared to the corresponding bulk materials. Catalysis is one material property that can become more pronounced at the nanoscale. By lowering energy requirements for chemical reactions, catalysts reduce production costs in diverse sectors of the economy, including medicine, transportation, environmental protection, oil and gas, food, and synthetic materials. Transition metals are an important class of catalysts capable of facilitating reduction and oxidation of molecular species. Since the discovery of transition metal catalysts nearly 200 years ago, certain metals were considered more active as catalysts (i.e., Pt, Pd, and Ru), while others (Au) appeared to have negligible catalytic activity as bulk materials. In recent years, gold nanoparticles (AuNPs) have become a fast-growing field of research owing to their unexpected catalytic properties not present in the bulk material. However, unsupported AuNPs are highly prone to flocculation and subsequent reduced catalytic activity. The choice of an appropriate aggregation-resistant stabilizing ligand for these nanoparticles is an important part of maintaining nanoscale catalytic properties. Additional stability is provided by anchoring AuNPs to support materials, allowing for dramatic improvements in catalyst lifetimes. This work discusses the development of novel diamond support materials for improving the stability of catalytically active AuNPs. Synthetic nanodiamond is a widely available, inexpensive, and robust material that has found applications in a wide range of commercial abrasives, lubricants, and composite materials. By exploiting the rich surface chemistry of nanodiamond, we have developed versatile catalyst support materials that offer unrivaled chemical and mechanical stability. Various nanodiamond surface modifications are readily prepared using a combination of chemical vapor deposition, photo-active polymer chemistry, and synthetic organic chemistry techniques. Control over the surface chemistry and properties of the resulting nanodiamond allow for increased stability of AuNPs via surface anchored thiol and amine moieties. The use of diamond as a support material should allow a wide variety of noble and nonprecious metal composite materials to be used as catalysts in harsh chemical environments not suitable for existing support materials. |
