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• CrZrO x /SiO 2 with different degree of ZrO 2 crystallinity were prepared and tested in non-oxidative propane dehydrogenation. • Their activity increases with the crystallinity, while the selectivity to propene is not affected. • Coke formation is the main reason for catalyst deactivation. • CrZrO x /SiO 2 showed good durability in 10 PDH/regeneration cycles under industrial relevant conditions. A series of SiO 2 -supported CrZrO x -based catalysts with same Cr content but different degrees of ZrO 2 crystallinity were synthesized by a simple impregnation-calcination method. The catalysts were studied for their activity, selectivity and on-stream stability in non-oxidative propane dehydrogenation (PDH) under industrially relevant conditions. They were characterized by complementary techniques such as XRD, BET, NH 3 -TPD, H 2 -TPR, operando UV–vis, EPR, Raman spectroscopy and TPO. The results demonstrate that ZrO 2 crystallinity plays an important role in propene formation. Although catalyst activity can be significantly augmented upon increasing the degree of crystallinity of ZrO 2 , no decrease in the selectivity could be observed at the same degree of propane conversion, i.e. 92 % at about 20 % conversion. The catalysts showed good durability in 10 PDH/oxidative regeneration cycles at 550 °C. [ABSTRACT FROM AUTHOR]

• Differently prepared bare ZrO 2 materials were tested in non-oxidative C 3 H 8 dehydrogenation. • Their activity and selectivity depends on the ability of ZrO 2 to release lattice oxygen under reducing conditions. • This catalyst property can be tuned by preparation method. • Controlled decomposition of ZrO(NO 3) 2 results in ZrO 2 with improved reducibility and high activity and selectivity. A detailed study was carried out on the factors affecting the activity and, particularly, selectivity of bare ZrO 2 in the non-oxidative propane dehydrogenation (PDH) to propene. To this end, a series of ZrO 2 samples differing in their redox and acidic properties, morphology and phase composition were synthesized by precipitation, sol-gel, glycine-nitrate combustion, template, digestion and calcination methods as well as through controlled thermal decomposition of zirconium oxonitrate. The ability of ZrO 2 to release its lattice oxygen in reducing atmosphere was identified as the main factor affecting PDH activity and propene selectivity. This is due to the fact that so generated surface zirconium cations (Zr cus) with lower coordination than their regular counterparts show higher activity for propene formation. As the latter sites strongly contribute to coke formation, the selectivity to this undesired product can be hindered through improving the ability of ZrO 2 to generate Zr cus sites under reducing conditions. [ABSTRACT FROM AUTHOR]