By using model catalysts allowing high spatial resolution of SPM technique, surface science provided insight into the elementary reaction processes at the atomic or molecular scale. Our researches aim for a detailed understanding of structural and electronic properties of model catalysts governing the reaction performance, based on well-defined surfaces of metal single crystals, and oxide or carbide layers on them. With these models, we are interested in the activation and conversion of the C-O bonds and C-H bonds of low-carbon molecules, revealing the surface active sites and reaction mechanisms at the molecular level.

    Besides, our group proposed an approach to mediate the surface free energy of the oxide support by preparation of an ultrathin oxide film on a bulk metal substrate to achieve thermally stable metal single atoms. The electronic effect from the oxide-metal interface leads to drastic surface property change of the grown thin oxide film. Then the surface free energy or chemical potential of the supported single metal atoms becomes comparable to or even lower than that of the supported thin oxide film. We have successfully applied this methodology to prepare a series of supported single-atom model catalysts.