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

Abstract

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.

A Mesoporous Cobalt Aluminate Spinel Catalyst for Nonoxidative Propane Dehydrogenation

“…In parallel, a significant amount of work has been directed towards alternative catalytic materials that might exhibit superior activity, selectivity, or stability for alkane dehydrogenation. With a focus on propane dehydrogenation, noble metal alloys, noble‐metal‐promoted oxides, binary/ternary Group IIIA metal oxides, acidic zeolites, isolated transition metal ions on oxide supports, and coordinatively unsaturated Zr on La‐modified ZrO 2 are examples of promising catalytic materials reported recently. Among these catalytic materials, catalysts based on 3d transition metals have been explored widely in alkane dehydrogenation because of their versatile chemical reactivity, earth abundance, and relatively low toxicity.…”

Coke Formation during Propane Dehydrogenation over Ga−Rh Supported Catalytically Active Liquid Metal Solutions

“…Other side reactions, such as hydrogenolysis or cracking, also contribute to the observed severe loss in activity . Even though regeneration of the catalyst by combustion of coke may be realised within short time frames, an alternating operation with dehydrogenation‐regeneration cycles drastically reduces the process efficiency while increasing operational costs and required investments. Hence, a high resistance of the applied catalyst against coking is highly desired and a key success factor for technical processes applying alkanes as feedstock for alkene production by catalytic dehydrogenation.…”

Investigation of the Isolated Cr(VI) Species in Cr/MCM‐41 Catalysts and its Effect on Catalytic Activity for Dehydrogenation of Propane

“…Though the former shows the advantage of reducing coke formation, it is still associated with the problem that the oxidation degree is hard to be controlled during actual industrial application, thus leading to safety issues and low propene yield inevitably . Consequently, non‐oxidative propane dehydrogenation (PDH) process has been gained much attention and realized in commercial applications …”