An　insurmountable　problem　for　silver-based　semiconductor　photocatalysts　is　their　poor　stability.　Here,　at　room　temperature,　AgI　with　different　concentrations　(5%,　10%,　20%　and　30%)　were　coupled　into　Ag2CO3,　producing　a　series　of　novel　AgI/Ag2CO3　composite　photocatalysts.　The　effects　of　AgI　addition　on　the　Ag2CO3　catalyst　for　photocatalytic　degradation　of　methyl　orange　(MO)　under　visible　light　irradiation　have　been　investigated.　Some　physicochemical　technologies　like　N-2　physical　adsorption/desorption,　powder　X-ray　diffraction　(XRD),　scanning　electron　microscopy　(SEM),　transmission　electron　microscopy　(TEM),　energy-dispersive　X-ray　(EDX)　spectroscopy,　X-ray　photoelectron　spectroscopy　(XPS),　and　UV-vis　diffuse　reflectance　spectroscopy　(UV-vis　DRS)　were　applied　to　characterize　these　products.　Results　show　that　the　photocatalytic　degradation　activity　of　AgI/Ag2CO3　photocatalyst　is　much　higher　than　that　of　pure　AgI　and　Ag2CO3.　With　the　optimal　content　of　AgI　(20　wt%),　the　AgI/Ag2CO3　exhibits　the　highest　photocatalytic　degradation　efficiency.　Its　first　order　reaction　rate　constant　(0.54　h(-1))　is　20　times　of　that　of　AgI　(0.026　h(-1))　and　3.6　times　of　that　of　Ag2CO3　(0.15　h(-1)).　The　characterizations　and　theory　calculation　show　that　AgI　and　Ag2CO3　have　suitably　matched　band　gap　structures.　The　formation　of　AgI/Ag2CO3　heterojunction　with　intimate　interface　could　effectively　increase　the　separation　efficiency　of　the　pairs　and　promote　the　production　of　＂　OH　and　Of　radicals,　which　brings　about　the　fast　degradation　rate　of　the　dye　and　an　increase　in　photocatalytic　stability.　(C)　2014　Elsevier　B.V.　All　rights　reserved.