posted on 2021-07-10, 14:30authored bySeung
Won Han, Hongjun Park, Jongho Han, Jeong-Chul Kim, John Lee, Changbum Jo, Ryong Ryoo
A PtZn alloy nanoparticle catalyst
for propane dehydrogenation
was synthesized by simple coimpregnation of Pt(NH3)4(NO3)2 with Zn(NO3)2 onto a mesoporous material, which was built with siliceous MFI zeolite
nanosheets. This mesoporous zeolite-supported PtZn catalyst exhibited
high activity and selectivity with remarkably long catalytic lifetime
compared with other PtZn catalysts loaded on γ-alumina, MCM-48
mesoporous silica, silica gel, and bulk MFI zeolite. When measured
under a high-purity propane flow at 580 °C, the PtZn/mesoporous
zeolite catalyst with metal loadings of 0.7 wt % Pt and 0.7 wt % Zn
lasted for more than 20 days before the propane conversion decreased
to half of its initial value. In comparison, other PtZn catalysts
were deactivated almost completely within a few days. Atomic-resolution
scanning transmission electron microscopic analysis revealed that
the mesoporous zeolite contained finely dispersed Pt1Zn1 intermetallic compound-type alloy nanoparticles, which could
effectively suppress catalyst deactivation. The mesoporous structure
and the surface silanol groups of the MFI zeolite are suggested to
play an important role in promoting the formation of intermetallic
alloy nanoparticles.