Selective　oxidative　dehydrogenation　(ODH)　of　light　alkanes　to　alkenes　over　metal　oxides　usually　obeys　a　redox　catalysis　cycle,　where　the　release　and　recovery　of　lattice　oxygen　play　a　key　role　in　catalytic　performance.　Therefore,　it　remains　a　challenge　to　prepare　metal　oxides　with　limited　reducibility,　such　as　TiO2,　as　a　dominant　active　component　rather　than　as　a　support　or　modifier　in　this　process.　Here,　we　find　a　significant　increase　of　ethane　ODH　performance　over　a　layered　TiO2　(M-TiO2)　catalyst,　which　is　in　situ　evolved　from　a　Ti3C2Tx　MXene　material　during　the　reaction.　The　reactivity　of　this　M-TiO2　is　4　times　higher　than　that　of　P25　TiO2,　with　an　excellent　ethylene　productivity　of　15.4　gC2H4　gcat–1　h–1　that　outperforms　the　previously　reported　catalysts.　Experimental　characterizations　and　theoretical　calculations　reveal　the　importance　of　Ti　and　oxygen　vacancy　defects　over　M-TiO2　on　the　conversion　of　C2H6.　The　Ti　vacancy　sites　can　stabilize　the　defective　structure　and　increase　the　reducibility　of　lattice　oxygen　to　reduce　the　activation　energy　barrier　of　ethane,　while　the　oxygen　vacancy　sites　facilitate　the　activation　of　O2　to　recover　lattice　oxygen.　©　2021　American　Chemical　Society