Introduction　of　surface　oxygen　vacancy　(Vo)　has　been　proved　to　be　a　powerful　method　to　promote　the　performance　of　H2S　selective　oxidation　by　improving　H2S　adsorption　and　O2　activation.　Nevertheless,　maximizing　the　oxygen　vacancy　concentration　remains　a　challenge　due　to　limited　exposed　surface.　Herein,　we　report　a　Fe-doped　TiO2_x　ultrathin　nanosheet　with　abundant　oxygen　vacancies　for　H2S　selective　oxidation　via　a　facile　citric　acid　assisted　hydrothermal　process.　One　of　the　cheapest　and　most　abundant　metals,　iron,　is　a　desirable　dopant　for　further　promoting　the　H2S　oxidation　activity　of　TiO2.　As　a　result,　the　Fe-doped　TiO2_　x　nanosheets　endowed　with　abundant　oxygen　vacancies　exhibited　nearly　100%　H2S　conversion　and　sulfur　selectivity　at　210　degrees　C　and　is　superior　to　those　of　most　reported　Ti-based　materials.　Furthermore,　through　in　situ　DRIFTS,　in　situ　Raman　and　EPR　spectra　of　H2S　oxidation,　the　reaction　pathway　for　selective　oxidation　of　H2S　over　Fe-doped　TiO2_x　with　abundant　oxygen　vacancies　was　revealed.　The　density　functional　theory　(DFT)　calculations　were　conducted　to　get　a　deeper　insight　into　the　effect　of　Fe-doping　on　the　electronic　structure　and　oxygen　vacancy　of　defected　TiO2.