The key to catalytic stability on sol–gel derived SnOx/SiO2 catalyst and the comparative study of side reaction with K-PtSn/Al2O3 toward propane dehydrogenation

• Side reactions comparison on SnO x /SiO 2 and K-PtSn/Al 2 O 3 in propane dehydrogenation. • Hydrogen spillover seems inessential for SnO x /SiO 2 compared with K-PtSn/Al 2 O 3. • The key to dramatical stability in SnO x /SiO 2 and its cause was discussed. • The possible coke formation pathway on SnO x /SiO 2 catalyst has been considered. Side reactions competing with propane dehydrogenation were studied on K-PtSn/Al 2 O 3 and SnO x /SiO 2 catalysts. The results showed that hydrogenolysis, hydrogenation, deep dehydrogenation, and coke formation occurred more pronouncedly on K-PtSn/Al 2 O 3, contrasting with the catalytic cracking result. Because of the higher total acidity on SnO x /SiO 2, measured by NH 3 -TPD, more catalytic cracking occurred on this catalyst. However, SnO x /SiO 2 showed a lower coke deposition, although the acid site can promote the coke formation. This contrast was not due to the spillover effect, which can suppress coke formation on the acid site. Essentially, the propylene hydrogenation, H 2 -TPD, and FTIR results demonstrate that SnO x /SiO 2 had a lower hydrogen spillover than that of K-PtSn/Al 2 O 3 . On the other hand, TPO results from propylene dehydrogenation and coke formation of propadiene illustrate that the key of distinguished SnO x /SiO 2 catalyst stability was owing to a low ability of coke precursor generation.