Difference in the Catalytic Activity of Atoms in the Corners and at the Edges of Gold Nanoparticles: Hydrogen Isotope Exchange Reaction.

The goal of this work is to investigate the catalytic activities of low-coordination atoms located in gold nanoparticles. Gold nanoparticles with sizes from 0.7 to 40 nm deposited on γ-AlO were used as a catalyst. Synthesized gold nanoparticles and prepared catalysts were characterized by HRTEM, SEM, XRD, DLS, and UV-Vis spectroscopy. The specific activity of gold nanoparticles towards the isotope exchange reaction at 77 K was studied as a function of nanoparticle size. The catalytic activity increases significantly when the particle size is less than 3 nm. The activities of low-coordination gold atoms located at the edges and in the corners are markedly different. Corner atoms (CN = 6) are more than 40 times more active in the reaction of hydrogen isotope exchange than edge atoms (CN = 7). TOF for atoms with coordination numbers CN = 6 and CN = 7 are 0.258 ± 0.020 and 0.006 ± 0.001 molecules site s, respectively. An equation was proposed for the dependence of the catalytic activity of the reaction on the particle size, the number of atoms on the surface, and their activity.