Co-based catalysts have gained significant attention in recent years due to their excellent ability to activate C-H bonds and high selectivity towards olefins, despite being a non-noble and environmentally unfriendly metal. However, further improvements are necessary for practical utilization, particularly in terms of activity and anti-carbon deposition capacity. In this study, we synthesized Al₂O₃ nanorods with abundant pentacoordinated Al³⁺ (Al³⁺_penta) sites. The supported Co on the Al₂O₃ nanorod (Co/Al₂O₃-NR) exhibited higher selectivity (>96% propylene selectivity) and stability (deactivation rate 0.15 h^-1), compared to Co supported on an Al₂O₃ nanosheet with fewer pentacoordinated Al³⁺ sites. Various characterizations confirmed that Co(II) mainly exists as CoAl₂O₄ rather than Co₃O₄ in the form of Co/Al₂O₃-NR, which inhibits the reduction of Co(II) to Co0 and improves catalyst stability accordingly.