The　adsorption　of　NO　and　NH3　gaseous　molecules　on　Mn3O4/TiO2　catalysts　is　studied　based　on　density　function　theory　and　the　corresponding　experiments　for　low-temperature　SCR　of　NOx　by　ammonia.　The　SCR　performances　of　the　Mn3O4/TiO2　catalysts　prepared　by　joint　precipitation　method　were　systematically　carried　out　in　the　temperature　range　of　90-300　degrees　C.　The　results　show　that　nitrogen　oxide　can　first　adsorb　on　the　manganese-terminal　to　form　nitrates　species,　and　then　NH3　are　more　inclined　to　adsorb　on　Bronsted　acid　sites.　Bridging　nitrate　and　bidentate　nitrate　can　be　turned　into　monodentate　nitrates,　and　NH4+　was　formed　when　there　is　ammonia　and　water　molecules　because　the　adsorption　and　dissociation　of　the　water　on　the　surface　of　the　catalyst　is　the　main　source　of　hydroxyl　groups.　It　is　indicated　that　L-H　mechanism　plays　a　major　role　in　NH3-SCR　process.　(C)　2015　Elsevier　B.V.　All　rights　reserved.