Catalyst supports based on ZnO-ZnAlO nanocomposites with enhanced selectivity and coking resistance in isobutane dehydrogenation

Development of coking resistant supports and catalysts for hydrocarbons conversion is challenging, especially when using such acidic materials as alumina. Apparently, this problem can be mitigated by using spinels that are less acidic, being, however, thermally stable. In this study, a series of ZnO-ZnAl 2 O 4 nanocomposites with different ZnO loading were prepared by urotropine-nitrate combustion synthesis to be used as supports for isobutane dehydrogenation catalysts. The nanocomposites were characterized by XRD, SEM, N 2 -physisorption analysis, EDS, H 2 -TPR, TPD of NH 3 and tested in isobutane dehydrogenation. Spinels with small amounts of ZnO displayed higher acidity and specific surface areas than samples with a higher ZnO content (30-40 mol%). At the same time, the maximum activity and the lowest selectivity to by-products (CH 4 and C 3 H 6 ) after 10 min of the reaction were observed for the nanocomposite containing 20 mol% of ZnO. The obtained nanocomposites have demonstrated better resistance to coking compared to commercial alumina. ZnO-ZnAl 2 O 4 obtained by urotropine-nitrate combustion synthesis can be effectively used as dehydrogenation catalyst supports. The ZnO content affects their properties and isobutane conversion, which passes through a maximum for 20 mol% of ZnO.