Reaction Mechanism and Deactivation Modes of Heterogeneous Catalytic Systems

Deactivation and Regeneration Study of a Co-Promoted MoO3 Catalyst in Hydrogenolysis of Dibenzofuran

“…However, the increased H 2 pressure could easily result in the excessive hydrogenation of aromatics. Remarkably, this pure oxide catalyst could be easily regenerated after deactivation by calcination. , During the reaction, the phase transition from MoO 3 species to an oxycarbohydride (MoO x C y H z ) species plays an important role in stabilizing active Mo 5+ species that could decrease the over-reduction to inactive Mo 4+ species. ,,, The deactivation of catalyst is often unavoidable, but a better understanding of the reasons for deactivation can help to find a kinetic method to decrease these unwanted consequences . Although the nature of pure and supported MoO 3 has been proved to affect activity and selectivity of HDO reactions, as far as we know, no systematic study has been performed to explore the promotional effect of Co on the MoO 3 catalyst and the deactivation/regeneration of the Co/MoO 3 catalyst for HDO of DBF.…”

Effects of Selected Promoters on Ni/Y-Al2O3 Catalyst Performance in Methane Dry Reforming

“…The primary products are H 2 and CO, which are suitable for industrial processes such as methanol, dimethyl ether, or Fisher-Tropsch reactions [3][4][5][6][7][8][9]. Fisher-Tropsch has been recognized as an important alternate technology to petroleum refining [10]. The main process reactions include:…”

“…Carbon formation by CH 4 decomposition is a structure sensitive reaction [2]. Several investigators have attributed catalyst instability and deactivation in reforming reactions to coke formation [10][11][12][13]. Numerous supported metal catalysts have been evaluated (Ni, Rh, Ru, Ir, Pd, and Pt) for this process [14][15][16][17][18][19][20][21][22].…”

Acid-catalyzed chemoselective C- and O- prenylation of cyclic 1,3-diketones

“…Unfortunately, the yield of 3a gradually decreased after each cycle. The polymerization of isoprene could not be avoided in the presence of the strong acid at high temperatures [53][54][55][56][57]. Thus, after several runs under the optimized conditions, the accumulated coke on the surface of Nafion led to its diminished catalytic activity.…”