Propane dehydrogenation (PDH) to propene is an important alternative to oil-based cracking processes, to produce this industrially important platform chemical1,2. The commercial PDH technologies utilizing Cr-containing (refs. 3,4) or Pt-containing (refs. 5–8) catalysts suffer from the toxicity of Cr(vi) compounds or the need to use ecologically harmful chlorine for catalyst regeneration9. Here, we introduce a method for preparation of environmentally compatible supported catalysts based on commercial ZnO. This metal oxide and a support (zeolite or common metal oxide) are used as a physical mixture or in the form of two layers with ZnO as the upstream layer. Supported ZnOx species are in situ formed through a reaction of support OH groups with Zn atoms generated from ZnO upon reductive treatment above 550 °C. Using different complementary characterization methods, we identify the decisive role of defective OH groups for the formation of active ZnOx species. For benchmarking purposes, the developed ZnO–silicalite-1 and an analogue of commercial K–CrOx/Al2O3 were tested in the same setup under industrially relevant conditions at close propane conversion over about 400 h on propane stream. The developed catalyst reveals about three times higher propene productivity at similar propene selectivity.

A few years ago, we introduced alternative-type bulk ZrO 2 -based catalysts for nonoxidative propane dehydrogenation (PDH). Currently, they belong to the state of the art catalysts owing to their environmental compatibility, high activity, propene selectivity, and durability. However, the structure−activity−selectivity relationships are still not appropriately understood. To close such gaps, we focused on elucidating the role of surface defects (coordinatively unsaturated Zr (Zr cus ) sites) and supported Rh nanoparticles (NPs) in Rh/ZrO 2 for activity and selectivity in the PDH reaction. Relevant physicochemical properties were analyzed by complementary experimental techniques, while details of catalyst functioning on an elementary-step level were derived from density functional theory calculations. Two types of Zr cus sites responsible for propane dehydrogenation were suggested to exist on the surface of ZrO 2 . Those located at Rh NPs reveal higher intrinsic activity owing to the positive effect of the metal on hydrogen desorption, which is the ratelimiting step in the PDH reaction over bare ZrO 2 . However, when the reduction degree of ZrO 2 is increased, propene strongly adsorbs on Rh, resulting in blockage of sites for hydrogen recombination. Consequently, the accelerating effect of the metal is hindered. Moreover, the strong propene adsorption plays a negative role in propene selectivity due to favoring conversion of the adsorbed propene into coke. The most active Rh/ZrO 2 catalyst revealed higher activity in comparison with the state of the art Ru/YZrO x and an analogue of commercial K-CrO x /Al 2 O 3 . It was also durable over 60 PDH/regeneration cycles at 550, 600, and 625 °C lasting 11 days in total.

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The synthesis of non-isocyanate polyurethanes (NIPUs) has recently gained great attention. In this respect, a bifunctional catalyst and an abundant metal catalyst system were investigated for the conversion of polyfunctional epoxides to gain general access to the corresponding cyclic carbonates as monomers for NIPU synthesis. A Ca-based catalytic system and a bifunctional ammonium salt were established for the synthesis of these monomers. In total, 14 terminal polyfunctional epoxides were converted to the corresponding carbonates in yields up to 99% and high purities. With regard to the one-pot synthesis of NIPUs directly from epoxides and CO2, the influence of the catalyst systems was evaluated. In general, both catalytic systems allowed the synthesis of NIPUs in a sequential one-pot procedure yielding polymers with a molecular mass of up to 19 kg·mol–1.

This paper demonstrates the potential of Eu2O3 and Gd2O3 as catalysts for non-oxidative propane dehydrogenation to propene.