Catalysis by Gold: Why Size Matters

Bulk gold is the most inert metal of all, however, when gold is finely dispersed on a support, it can be a very active catalyst for oxidation and hydrogenation reactions. X-ray absorption spectroscopy showed that the smaller the gold particles are, the shorter the gold–gold bond length is. The smaller particles also have an altered electronic structure, as they undergo less hybridization between the s, p, and d orbitals than the larger particles. The d band narrows and moves closer to the Fermi level. As a result, hydrogen, oxygen, and CO adsorb on the metal surface and the nano-sized metal particles can become catalytic