Direct Visualization of the Formation about Inverse Catalyst CoO(x)/Pt(111)

In nonhomogeneous catalysts, the catalyst formation process plays a critical role in determining catalytic performance. However, there is limited research on visualizing the synthesis process on the atomic scale. In this study, we successfully grew cobaltocene films on Pt(111) under ultrahigh vacuum (UHV) conditions using an ultralow temperature atomic layer deposition technique. To simulate real-world conditions, we investigated the effects of oxygen and temperature on cobaltocene (CoCp2) thin films by introducing oxygen into an ultrahigh vacuum chamber. The characterization of the formation process was conducted in detail by scanning tunneling microscopy (STM). Additionally, we elaborate on the entire process of treating Pt single crystals by using the E-beam method. Given the significance of cobaltocene adsorption in the overall process, we investigated its behavior at different exposure times. At an exposure time of 30 s, cobaltocene was observed to be dispersed on the surface as atomic clusters. With longer exposure times, the surface of Pt(111) became fully covered by cobaltocene molecules, reaching a height of about 70 pm. Subsequently, through oxidation annealing in 1 × 10–7 mbar O2 at 673 K, amorphous cobaltocene films were transformed into CoO(x) islands with crystal structures. To assess the stability of CoO(x) islands on Pt(111) at different temperatures, ab initio molecular dynamics (AIMD) and density functional theory (DFT) calculations were performed. Molecular dynamics simulations were performed on the two heterostructures at 623 and 673 K, respectively. After 2000 fs cycles, both the energy and temperature gradually stabilized following a brief oscillation, eventually reaching equilibrium.