Array modified PdAg/Al2O3 catalyst for selective acetylene
hydrogenation: Kinetics and thermal effect optimization
Abstract
Aiming at the low surface area of high-temperature-calculated alumina
limits the dispersion of active metals, an in-situ growth method is
applied to fabricate the alumina array modified spherical alumina.
Taking the modified alumina as support, the highly dispersed PdAg
catalyst for selective acetylene hydrogenation is synthesized, which
exhibits a remarkable enhanced intrinsic activity. Moreover, when the
acetylene conversion reached 90%, the ethylene selectivity remains
89%. Preferred selectivity is assigned to more isolated Pd sites and
high electronic density, which facilitates the desorption of the
resulting ethylene. More importantly, the modified catalyst exhibits
good structural stability and resistance to carbon deposition. From one
aspect, the decrease of heat production rate over active site is
conducive to reduce the reaction heat accumulation, thereby avoiding the
formation of hot-spots over the catalyst. From another point of view,
the outer opening pore structure of the modified alumina are benefit for
the heat transfer.