A　new　method　entitled　Ultrasound-assisted　Membrane　Reduction　(UAMR)　was　developed　to　prepare　highly　dispersed　monometallic　Rh/gamma-Al2O3　and　bimetallic　AuRh/gamma-Al2O3　catalysts.　In　this　process,　the　reductant　(NaBH4)　solution　is　infiltrated　through　ceramic　membrane　tubes　to　a　flowing　suspension　mixture　of　noble　metal　precursors　and　gamma-Al2O3,　and　then　the　noble　metal　ions　were　reduced　and　deposited　on　the　gamma-Al2O3　to　form　nanoparticles　or　clusters　on　the　surface　of　the　carrier.　The　smaller　noble　metal　nanoparticles　(similar　to　5　nm)　and　higher　activity　for　the　selective　catalytic　reduction　(SCR)　of　NO　by　propylene　at　low　temperature　were　obtained　over　the　catalysts　prepared　by　the　new　method,　compared　to　the　catalysts　prepared　by　conventional　impregnation　method.　The　AuRh/gamma-Al2O3　catalyst　with　0.33　wt%　Au　and　0.17　wt%　Rh　(M-Rh:M-Au　=　1:1)　loading　exhibited　higher　propylene　and　NO　conversions　but　lower　NO　conversion　to　N-2　than　0.5　wt%　Rh/gamma-Al2O3　catalyst,　both　of　which　were　fabricated　by　the　new　preparation　process.　The　stronger　NO　adsorption　capability　and　formation　of　surface　nitrates　were　validated　over　bimetallic　AuRh/gamma-Al2O3　catalysts　in　NO-TPD　experiment.　The　synergistic　effect　of　bimetallic　system　could　improve　the　performance　of　SCR　of　NO　and　reduce　the　cost　for　platinum　group　metals　based　catalysts.　(C)　2009　Elsevier　B.V.　All　rights　reserved.