ZrO2 -Based Alternatives to Conventional Propane Dehydrogenation Catalysts: Active Sites, Design, and Performance.

Non-oxidative dehydrogenation of propane to propene is an established large-scale process that, however, faces challenges, particularly in catalyst development; these are the toxicity of chromium compounds, high cost of platinum, and catalyst durability. Herein, we describe the design of unconventional catalysts based on bulk materials with a certain defect structure, for example, ZrO2 promoted with other metal oxides. Comprehensive characterization supports the hypothesis that coordinatively unsaturated Zr cations are the active sites for propane dehydrogenation. Their concentration can be adjusted by varying the kind of ZrO2 promoter and/or supporting tiny amounts of hydrogenation-active metal. Accordingly designed Cu(0.05 wt %)/ZrO2 -La2 O3 showed industrially relevant activity and durability over ca. 240 h on stream in a series of 60 dehydrogenation and oxidative regeneration cycles between 550 and 625 °C.

Unexpectedly high activity of bare alumina for non-oxidative isobutane dehydrogenation.

Bare alumina shows surprisingly high activity in non-oxidative dehydrogenation of isobutane to isobutylene. The activity is related to surface coordinatively unsaturated Al sites (Alcus), which are created upon removal of OH groups during alumina treatment at high temperatures. Alcus and neighbouring lattice oxygen represent the active site for isobutane dehydrogenation.

Bulk binary ZrO2-based oxides as highly active alternative-type catalysts for non-oxidative isobutane dehydrogenation.

Bulk binary ZrO2-based oxides efficiently catalyse non-oxidative dehydrogenation of isobutane to isobutylene. Their activity strongly depends on the kind of second metal oxide. So designed CrZrOx showed superior activity to industrially relevant catalysts with supported Pt or CrOx species. It was also stable under alternating dehydrogenation and oxidative regeneration cycles over ca. 110 h under different reaction conditions between 550 and 600 °C.