Effect of alumina polymorph on the dehydrogenation activity of supported chromia/alumina catalysts

•A set of 1ML CrOx/Al2O3 catalysts was prepared with γ-, δ-, (δ + θ)-, η- and θ-Al2O3.•Amounts of Cr6+, Cr5+, Cr3+ species are independent upon alumina structure.•Relative number of Cr3+ in Cr2O3-like clusters increases with LAS density on Al2O3.•Dehydrogenation activity (per m2) and stability grow with LAS density on Al2O3.•Aluminas’ LAS were proposed to be an anchoring sites for Cr3+Ox species.