MIL-53(Fe)　was　synthesized　using　a　＂modulator　approach＂　that　utilizes　acetic　acid　(HAc)　as　an　additive　to　control　the　size　and　morphology　of　the　resulting　crystals.　We　demonstrate　that　after　activation　under　vaccum　at　100　degrees　C,　the　MIL-53(Fe)　functions　well　for　H2S　selective　oxidation.　The　introduction　of　acetic　acid　in　the　presence　of　benzene-1,4-dicarboxylic　acid　(H2BDC)　would　result　in　a　series　of　MIL-53(Fe)　nanocrystals　(denoted　as　MIL-53(Fe)-xH,　x　stands　for　the　volume　of　added　HAc　with　morphology　evoluting　from　irregular　particles　to　short　hexagonal　columns.　The　vacuum　treatment　facilitates　the　removal　of　acetate　groups,　thus　generating　Fe3+　Lewis　acid　sites.　Consequently,　the　resulted　MIL-53(Fe)-xH　exhibits　good　catalytic　activity　(98%　H2S　conversion　and　92%　sulfur　selectivity)　at　moderate　reaction　temperatures　(100-190　degrees　C).　The　MIL-53(Fe)-5H　is　superior　to　the　traditional　iron-based　catalysts,　showing　stable　performance　in　a　test　period　of　55　h.　(C)　2021,　Dalian　Institute　of　Chemical　Physics,　Chinese　Academy　of　Sciences.　Published　by　Elsevier　B.V.　All　rights　reserved.