Influences of regeneration atmospheres on structural transformation and renderability of fluidized catalytic cracking catalyst

The regeneration of fluidized catalytic cracking(FCC)catalysts is an essential process in petroleum processing.The current study focused the regeneration reaction characteristics of spent fluidized catalytic cracking catalyst(SFCC)at different atmospheres with influences on pore evolution and activity,for a potential way to reduce emission,produce moderate chemical product(CO),and maintain catalyst activity.The results show that regeneration in air indicates a satisfaction on removing coke on the catalyst surface while giving a poor effect on eliminating the coke inside micropores.This is attributed that the combustion in air led to a higher temperature and further transformed kaolinite phase to silicaaluminum spinel crystals,which tended to collapse and block small pores or expand large pores,with similar results observed in pure O_(2)atmosphere.Nevertheless,catalysts regenerated in O_(2)/CO_(2)diminished the combustion damage to the pore structure,of which the micro porosity after regeneration increased by 32.4% and the total acid volume rose to 27.1%.The regeneration in pure CO_(2)displayed low conversion rate due to the endothermic reaction and low reactivity.The coexistence of gasification and partial oxidation can promote regeneration and maintain the original structure and good reactivity.Finally,a mechanism of the regeneration reaction at different atmospheres was revealed.

Densely packed overlayer of iron phthalocyanine molecules grown on single-layer graphene

The formation of densely packed overlayer of iron phthalocyanine(FePc) molecules on single-layer graphene(SLG) epitaxially grown on Ru(0001) is studied by means of low temperature scanning tunneling microscopy. We show that the FePc molecules form single molecular arrays, ordered honeycomb lattice, Kagome lattice and square lattice with increasing molecular coverage. The densely packed square lattice of the molecular layer is modulated by the moire pattern of SLG/Ru(0001). The superposition of the square lattice of the molecular layer on the hexagonal lattice of SLG moire pattern leads to the formation of a larger strip moiré pattern. This coverage-dependent self-assembling behavior of FePc on SLG/Ru(0001) is mainly driven by the inhomogeneous electronic structure of graphene moire pattern, due to spatial-dependent interfacial charge transfer between SLG and Ru(0001) substrate.