Carbonate Formation and Decomposition on Atomic Oxygen Precovered Au(111)

摘要

The carbonate formation and decomposition (CO_3 ←→ CO_2 + O_a) reaction on gold is important from the point of view of low-temperature CO oxidation. Carbonate formation has been proposed as a possible reaction intermediate in CO oxidation in several investigations of supported and unsupported gold clusters. Therefore, an understanding of this reaction on Au(111) may provide additional insight. Carbonate formation and decomposition went undetected in previous studies on Au(110) and Au(111). However, a surface carbonate was readily formed when oxygen precovered Ag(110) was exposed to CO_2 at 300 K. This surface carbonate decomposes to produce CO_2 at 485 K and the remaining oxygen atoms recombinatively desorbed at 590 K. Owing to its similarity with silver, we would anticipate equally facile carbonate formation and decomposition reactions on gold. Similar reactions have also been reported on other surfaces.