However, the low specific surface area of cerium oxide leads to the production of large copper particles, which do not contribute to the catalyst activity.
Addition of Na decreased the stability, because it promoted the formation of inactive CuO particles; in addition, migration of Cu2+ to a different coordination environment also seemed to contribute to the catalyst deactivation.
Nitrogen compounds and coke [37, 38], which could contribute to the catalyst deactivation during the heavy oil hydrocracking process, does not exist in the model reactant system.
This suggests that the top zone of the catalyst bed contributed the most activity and was where the reaction took place.
This suggests that the middle and bottom zones of the catalyst bed contributed the most activity, where the reaction took place.
We show that exposing the Cu foil to oxygen, either present as residuals in the Ar feedstock or precisely dosed using the Ar/O2 gas line, effectively contributes to reduce the catalyst carbon content prior to graphene growth and hence significantly decreases the nucleation site density.
Moreover, the sub-monolayer Au coating on the surface also contributes to the enhanced catalyst durability by inhibiting the Pt oxidation.
Because surface hydroxides play an important role in the catalytic cycle of the WGSR, the basic and hygroscopic nature of the hydroxide salts contributes to the improvement in catalyst performance.
Because of the low O2/CO molar ratio, the high CO removal conversion and the long-term durability, the Ru catalyst contributes to the development of residential PEFC cogeneration systems.
Our results suggest that the surface of the amorphous MoSx catalyst is dynamic: while the initial catalyst activation forms the primary active surface of amorphous MoS2, continued transformation to the crystalline phase during electrochemical operation could contribute to catalyst deactivation.
