Recently we have been investigating the use of Atomic Layer Deposition (ALD) to prepare catalysts with improved selectivity. ALD has been used to modify the surface of supports, to create unique bimetallic species and to protect catalysts from the detrimental effects of sintering and coking. Following a short review of the ALD technique this talk will describe recent studies centered on improving the synthesis of propylene produced via the dehydrogenation of propane (PDH). Increasing PDH yield via higher catalyst activity, lifetime, or selectivity represents a significant energy and economic savings. Using Pt dispersed on alumina extrudate supports as a commercially relevant model system, we demonstrate that Al2O3 ALD overcoats, used to tailor metal-active sites, can increase PDH yield and selectivity. Application of a 6–8 Å thick layer of ALD Al2O3 on low-surface area alumina supports of ∼90 m2/g surface area yields the optimal combination of stability and activity, while increasing propylene selectivity from 91 to 96%. Increased stability following steam deactivation occurs because the Al2O3 overcoat prevents the Pt nanoparticles from sintering. It appears that the ALD overcoat selectively binds to the undercoordinated sites on the Pt nanoparticles, while leaving the more selective terrace sites available for dehydrogenation.

Improved catalyst selectivity via ALD overcoating

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.