Zn-based Al<sub>2</sub>O<sub>3</sub>-suported materials have been proposed as inexpensive and environmentally friendly catalysts for the direct dehydrogenation of propane (PDH), however, our understanding of these catalysts’ structure and deactivation routes is still limited. Here, we correlate the catalytic activity for PDH of a series of Zn-based Al<sub>2</sub>O<sub>3</sub> catalysts with their structure and structural evolution. To this end, three model catalysts are investigated. (i) ZnO/Al<sub>2</sub>O<sub>3</sub> prepared by atomic layer deposition (ALD) of ZnO onto γ-Al<sub>2</sub>O<sub>3 </sub>followed by calcination at 700 °C, which yields a core-shell spinel zinc aluminate/γ-Al<sub>2</sub>O<sub>3</sub> structure. (ii) Zinc aluminate spinel nanoparticles (Zn<sub>x</sub>Al<sub>y</sub>O<sub>4</sub> NPs) prepared via a hydrothermal method. (iii) A reference core-shell ZnO/SiO<sub>2</sub> catalyst prepared by ALD of ZnO on SiO<sub>2</sub>. The catalysts are characterized in detail by synchrotron X-ray powder diffraction (XRD), Zn K-edge X-ray absorption spectroscopy (XAS), and <sup>27</sup>Al solid state nuclear magnetic resonance (ssNMR). These experiments allowed us to identify tetrahedral Zn sites in close proximity to Al sites of a zinc aluminate spinel phase (Zn<sub>IV</sub>–O–Al<sub>IV/VI</sub> linkages) as notably more active and selective in PDH relative to the supported ZnO wurtzite phase (Zn<sub>IV</sub>–O– Zn<sub>IV</sub> linkages) in ZnO/SiO<sub>2</sub>. The best performing catalyst, 50ZnO/Al<sub>2</sub>O<sub>3</sub> gives 77% selectivity to propene (gaseous products based) at 9 mmol C<sub>3</sub>H<sub>6</sub> gcat−1 h<sup>−1</sup> space time yield (STY) after 3 min of reaction at 600 °C. On the other hand, the core-shell ZnO/Al<sub>2</sub>O<sub>3</sub> catalyst shows an irreversible loss of activity over repeated PDH and air-regeneration cycles, explained by Zn depletion on the surface due to its diffusion into subsurface layers or the bulk. ZnxAlyO<sub>4</sub> NPs gave a comparable initial selectivity and catalytic activity as 50ZnO/Al<sub>2</sub>O<sub>3</sub>. With time on stream, Zn<sub>x</sub>Al<sub>y</sub>O<sub>4</sub> NPs deactivate due to the formation of coke at the catalyst surface, yet the extend of coke deposition is lower than for the ZnO/Al<sub>2</sub>O<sub>3</sub> catalysts, and the activity of Zn<sub>x</sub>Al<sub>y</sub>O<sub>4</sub> NPs can be regenerated almost fully using calcination in air.<br>
Structural Evolution Patterns of FCC-Type Gold Nanoclusters