Fe-based　catalysts　have　a　great　potential　to　be　used　for　selective　catalytic　reduction　(SCR)　of　NOx　with　NH3　reaction　due　to　their　low　cost,　nontoxicity　and　excellent　catalytic　activity.　The　aim　of　this　paper　is　to　investigate　Ce　doping　effect　on　activity　of　NH3-SCR　over　the　FeOx/TiO2　catalyst.　In-situ　diffuse　reflectance　infrared　fourier　transform　(DRIFT)　technology　was　utilized　to　verify　the　adsorbed　species　on　the　surface　of　FeOx/TiO2　and　FeOx-CeO2/TiO2　catalysts.　With　respect　to　the　obtained　results,　among　the　four　catalysts　studied,　the　FeOx-CeO2/TiO2　with　the　FeOx/CeO2　ratio　of　3/8　shows　the　best　NO　conversion　more　than　98%　in　the　temperature　range　of　230-350　degrees　C.　The　active　centers　for　NH3　adsorption　and　activation　are　assigned　to　Lewis　acid　sites　over　the　FeOx-CeO2/TiO2　and　monodentate　nitrates　can　act　as　the　key　intermediate　in　the　NH3-SCR.　Moreover,　both　of　Langmuir-Hinshelwood　and　Eley-Rideal　mechanisms　are　observed　over　the　FeOx-CeO2/TiO2　catalysts　in　the　SCR.　(C)　2020　Published　by　Elsevier　B.V.　on　behalf　of　Chinese　Society　of　Rare　Earths.