Mechanism of potassium loss by desorption from an iron oxide catalyst for the styrene process

摘要: Several types of experiments have been done with molecular beam and mass spectrometric methods to characterize the desorption processes potassium from a commercial styrene (potassium promoted iron oxide) catalyst. The loss as K is found be mainly thermal, an activation energy close 1.0 eV (97 kJ/mole), which probably associated release initially bound positions in bulk. directly measured rate appears too small account for experimentally observed total loss. A new mechanism electronically excited but not easily field ionizable atoms detected barrier 1.7 (164 kJ/mole). Excited states may important both through direct emission atoms, since give rise cluster formation at surface more rapid clusters Kn.