On the contrary, a slight deactivation was observed in the impregnated Pd Cu catalysts as a consequence of metal sinterisation.
For loadings above 7.5 wt %, a step change in activity and selectivity was observed, while loadings of only 5 wt % caused even a slight deactivation as compared to the unmodified catalyst.
A slight deactivation leading to decreased acidity was observed for operational temperatures greater than 350 °C, although catalysts regeneration was possible.
The contrast "decade distance > overall distance" revealed no activation in intraparietal cortex but only a slight deactivation in the left angular gyrus.
The results indicated a slight catalyst deactivation because of the leaching of the CaO active species into the reaction medium [27].
Times of stream (TOS) experiments have shown that conventional hydrotreating catalyst suffers of slight deactivation as the reaction proceeds.
Several possible causes of slight deactivation are proposed, which mainly includes the weakened interfacial contact, partial ethylenediamine (en) ligands dissociation or substitution by H2O, OH− and S2−, repair of S vacancies and partial oxidation of Cd-S bonds.
The influence of SO2 on NO removal was found to be temperature dependent, at temperature below 325 °C, slight deactivation was observed, while a promotion was achieved above 350 °C.
Ni Al2O3 catalyst showed a stable catalytic performance without significant catalyst deactivation during the reaction extending over 3000 min, while Ni/Al2O3 catalyst exhibited a stable catalytic performance at the initial stage but experienced a slight catalyst deactivation in the long run.
The Cr catalysts also show some slight deactivation.
