Atomic Visualization for Dissociative Adsorption of Hydrogen on Co(0001)

The adsorption and dissociation of hydrogen on the Co(0001) surface were investigated by using density functional theory (DFT) calculations and scanning tunneling microscopy (STM) experiments. DFT calculations revealed a negligible energy barrier for H2 dissociation upon adsorption, with H atoms preferentially occupying hollow sites (fcc and hcp). The facile diffusion of H atoms across the surface was also observed. A phase diagram for H adsorption on Co(0001) was constructed, identifying the most stable phases under varying conditions. STM experiments successfully visualized the atomic arrangements of both the 1H-(1 x 1) and 2H-(2 x 2) phases. Precise attribution of detailed STM imaging features is established for the adsorption of H on Co(0001), confirming the theoretical predictions and providing direct experimental evidence for the dissociative adsorption of hydrogen on Co(0001).