“…Titanium dioxide (TiO 2 ) has been widely used in the field of environmental protection and energy conservation such as photocatalysis, , heterogeneous catalysis, ,, gas sensors, − and dye-sensitized solar cells − due to its excellent photoelectric properties, nontoxic nature, physical chemical stability, high catalytic activity, and low costs. Au nanoparticles supported on TiO 2 have been widely used in many important catalytic reactions. ,− The structures of Au nanoparticles on TiO 2 have been studied using high-resolution electron microscopy (HREM), and researchers found that the catalytic activity strongly depends on the size of Au particles as well as the crystalline structure of TiO 2 supports. , Density functional theory (DFT) calculations were employed to investigate the interactions between Au and TiO 2 support − as well as the reaction mechanisms for reactions catalyzed by Au/TiO 2 catalysts. ,− Catalytic hydrogenation is an important type of reaction in which Au nanoparticles supported on TiO 2 exhibit their particular catalytic capability such as in CO 2 reduction, ,,− the hydrogenation of unsaturated C–C bonds, ,, the selective hydrogenation of α,β-unsaturated carbonyl compounds such as aldehydes and ketones, ,,− and the hydrodeoxygenation of biomass-derived compounds. ,,, In these hydrogenation processes, the adsorption and dissociation of hydrogen on the supported metal particles are crucial steps and sometimes rate-limiting . Interactions between hydrogen molecule and Au atoms/small gold clusters have been theoretically studied − which show that the flexibility of the cluster structure and the size of Au cluster play important roles for H 2 adsorption and dissociation.…”