•Ag/bauxite　possesses　much　higher　SCR　activity　below　250°C　than　Ag/Al2O3.•Ag/bauxite　possesses　much　stronger　tolerance　against　SO2　and　H2O　than　Ag/Al2O3.•The　compositions　of　bauxite　are　beneficial　to　improve　SCR　performances.　A　series　of　Ag/bauxite　catalysts　were　applied　in　H2-promoted　selective　catalytic　reduction　(SCR)　of　NOx.　In　comparison　with　3Ag/Al2O3,　3Ag/bauxite　exhibits　higher　catalytic　activity　at　low　temperature,　stronger　resistance　to　SO2　poisoning　and　better　regenerability　in　SCR　of　NOx.　NOx　conversion　of　3Ag/bauxite　at　100-200°C　is　more　than　60%,　which　is　much　higher　than　less　than　7%　in　3Ag/Al2O3.　NH3-TPD　and　in　situ　DRIFTS　studies　confirm　the　presence　of　Lewis　and　Brønsted　acid　sites　in　Ag/bauxite,　and　Lewis　acid　sites　are　the　major　acid　sites.　H2-TPR,　UV-vis,　in　situ　DRIFTS　and　DFT　calculation　show　that　FeOx　and　metallic　Ag　clusters　are　main　active　species　in　SCR　of　NOx　at　low　temperature.　©　2014　Elsevier　B.V.