Different influences of V2O5/Al2O3 introduction on initial conversion of n-heptane over fresh and equilibrium ZSM-5 catalyst

•Influences of V2O5/Al2O3 on initial reaction of n-C7H16 over ZSM-5 were studied.•The influences differed greatly in the fresh and equilibrium ZSM-5 catalyst system.•V2O5/Al2O3 is supposed to offer another reaction pathway for the initial reaction.

Previous studies showed that the introduction of V2O5/Al2O3 could improve catalytic performances of ZSM-5 catalyst for n-heptane cracking. In order to clarify influences of V2O5/Al2O3 introduction on the initial reaction of n-heptane, performances of n-heptane cracking over fresh and equilibrium ZSM-5 catalyst without and with V2O5/Al2O3 introduction were comparatively studied in this paper. The results showed that the introduction of V2O5/Al2O3 brought significant influences to initial reactions of n-heptane over the equilibrium ZSM-5 catalyst. The initial reaction rate was significantly improved, and the product selectivity was greatly changed by V2O5/Al2O3 introduction. But no such effect was observed for the fresh ZSM-5 catalyst. It was supposed that the presence of V2O5/Al2O3 offered another pathway for initial conversion of n-heptane, and this reaction path played a more important role in the reaction over the mixed V2O5/Al2O3 and equilibrium ZSM-5 catalyst.