The production of propylene via oxidative dehydrogenation (ODHP) offers the potential to significantly reduce the energy demand compared to conventional cracking routes due to its exothermicity. However, low propylene selectivity and the need for expensive air separation still hinder the commercial implementation of ODHP. Herein, we present a chemical looping-based scheme for propylene production via oxidative dehydrogenation (CL-ODHP), offering an in-situ supply of gaseous oxygen from Sr1-xCaxFeO3-type perovskite oxygen carriers (OC), while converting propane to propylene over a physically separated VOx-SiO2 catalyst. To prevent the overoxidation of propane to COx at the sutface of the OC, different alkali metal-based modifications were investigated. Our experiments proved that a solid Na2CO3 surface layer only partially reduce propane overoxidation, whereas a modification with molten NaNO3 completely inhibits the combustion of the carbonaceous feed by the OC. In-situ Raman spectroscopy showed that NaNO3 on the surface of the OC forms a non-porous diffusion barrier for hydrocarbons, impeding their direct interaction with the OC, while allowing gaseous oxygen to permeate. The successful surface modification enables a stable CL-ODHP performance over 50 redox cycles at 500 °C, reaching 8 % propane conversion at 70 % propylene selectivity, thus slightly outperforming the benchmark VOx-SiO2 catalyst under regular ODHP conditions with the co-feeding of oxygen. The surface modification of the OC using NaNO3 and separating the OC and catalyst allow for flexibility, as they can be tailored individually. This concept may therefore present a versatile platform for further reactions requiring gaseous oxygen or air separation.