IR study of active sites for n-heptane isomerization over MoO sub(3-ZrO) sub(2)

The property of acidic sites on MoO sub(3-ZrO) sub(2) was studied for n-heptane isomerization. A 2,6-lutidine IR study showed that the introduction of MoO sub(3 on ZrO) sub(2) partially eliminated the absorbance band at 1605 cm super(-1 ascribed to Lewis acid sites corresponding to the presence of the monoclinic phase of ZrO) sub(2) and developed several Broensted and Lewis acid sites with different acidic strengths. MoO sub(3-ZrO) sub(2) possesses a large number of relatively weak Lewis and Broensted acid sites as well as strong acid sites. The active protonic acid sites in n-heptane isomerization were formed from molecular hydrogen through a spillover mechanism with the involvement of doublet bands at 1595 and 1580 cm super(-1 ascribed to the Lewis acid sites corresponding to the presence of the tetragonal phase of ZrO) sub(2). No catalytic activity of MoO sub(3-ZrO) sub(2) for n-heptane isomerization was observed in the absence of the doublet bands at 1595 and 1580 cm super(-1 and hydrogen in the gas phase.)