Deactivation of Pd Acetoxylation Catalysts:Direct Observations by XPS Investigations

摘要

Catalyst deactivation is a problem of great concern in industrial catalytic processes.Hence,prevention of catalyst deactivation poses substantial challenges in the design and operation of large-scale catalytic processes.The usual way to overcome the deactivation problem is to modify the catalyst composition by using different promoters.Although various promoters have been used for different oxidation reactions,their precise role is not known.Unfortunately,most of the interpretations on the role of promoters are rather hypothetical probably owing to the lack of information about the exact surface structure.Among the known promoters,bismuth has very attractive properties as a promoting element in numerous heterogenous oxidation catalysts,particularly in association with noble metals.