Single-molecule study of photo-catalytic reactions on oxide surfaces

在单分子水平上研究了Cu（110）上羟基与氢原子的反应机理和动力学。通过STM尖端的隧道电子，激发水分子的振动模式，使其衰变成氢原子的运动。通过与理论小组的合作，我们确定了振动模式及其频率的身份。研究还发现，表面的氧原子在将水分子解离成羟基二聚体中起着至关重要的作用。这说明杂质氧原子是水分子在铜表面反应的活性位点。另一方面，硫原子不与水分子反应；揭示了两个碳原子在催化活性上的本质区别。

We studied the mechanism of reaction and dynamics of hydroxyl species and hydrogen atom on Cu(110) at a single-molecule level. By tunnel electrons from the STM tip, the vibration mode of a water molecule is excited, which decays into the motion of hydrogen atom. By collaboration with theory groups, we determined the identity of the vibration modes and their frequencies. It was also found that the oxygen adatom on the surface plays a crucial role in dissociating water molecules into hydroxyl dimer. This indicates that the impurity oxygen atom is the active site for the reaction of water molecules on the copper surface. On the other hand, sulfur atom is not reactive to water molecules; we reveal essential difference between two chalcogen atoms in the catalytic activity.