Fig. 3: MALDI FT-ICR mass spectra of the liberated carbonaceous deposits.

The mass spectra of the liberated carbonaceous deposits obtained from the used up-layer SAPO-34 catalysts by HF dissolution-CCl4 extraction after MTO reaction with WHSV of 4 h−1 at 475 °C for 30 min (a), at 475 °C for different durations (5–130 min) (b), at different temperatures (350–475 °C) (c). d The mass spectra of the liberated carbonaceous deposits obtained from the used bottom-layer catalysts after MTO reaction at 475 °C for different durations (5–130 min).