Efficient synthesis of light olefins from renewable resources remains a major challenge. We request 6 days on MAPS to carry out inelastic neutron scattering (INS) study of a multifunctional zeolite catalyst (TaAlS-1: Ta-doped MFI zeolite) for the highly selective conversion of methanol to propene. The proposed study will investigate the vibrational spectroscopy (e.g., C-H and O-H stretching modes) of the catalyst, adsorption of guest molecules (methanol and dimethyl ether) and any possible reaction intermediates (e.g., alkenes) on catalyst surface. In particular, this study aims to reveal the roles of Ta(V) sites and Si-O(H)-Al groups in the binding to guest molecules and in the catalytic reactions. This recently-discovered multifunctional catalyst (unpublished) exhibit record high selectivity of propene and propene/ethene ratio for methanol conversion.