A hollow nano-MgF₂ supported Fe (Fe/hollow nano-MgF₂) nanocatalyst is prepared which is capable of exhibiting excellent stability under extremely harsh conditions, and has tailored acidity with weak and medium strengths. In the gas-phase fluorination of 1,1,1,3-tetrachloropropane with HF to 3,3,3-trifluoropropene, Fe/hollow nano-MgF₂ exhibits a similar activity to but a much longer lifespan than classical chromia catalysts under the same reaction conditions due to its tailored medium-strength acid sites and stable nanostructure.