Due　to　increasingly　serious　environmental　problems,　many　researchers　are　investigating　green　clean-energy　to　solve　the　world＇s　energy　supply　issues.　So　the　strategy　that　Au　nanoparticles　(Au　NPs)　and　bismuth　sulfide　(Bi2S3)　NPs　are　used　to　evenly　decorate　TiO2　nanotube　arrays　(TiO2　NTAs)　was　carried　out.　Composite　materials　demonstrated　enhanced　solar　light　absorption　ability　and　excellent　photoelectrochemical　performance.　This　was　attributed　to　the　presence　of　Bi2S3　NPs　with　a　narrow　band　gap　and　the　decoration　with　noble　metallic　Au　NPs　which　resulted　in　local　surface　plasmon　resonance　(LSPR)　effects.　The　Au/Bi2S3@TiO2　NTAs　composites　exhibit　improved　photocatalytic　activity　for　the　degradation　of　methylene　blue　(MB)　under　irradiation　of　UV　and　visible　light.　Moreover,　the　Au/Bi2S3@TiO2　NTAs　exhibits　high　fluorescence　emission　at　822　nm.　Due　to　the　better　binding　affinity　between　Bi2S3,　TiO2　and　Fe3+　ions,　the　synthesized　nanocomposites　exhibit　high　selectivity　to　Fe3+　ions.　The　number　of　binding　sites　for　Au/Bi2S3@TiO2　NTAs　was　estimated　to　be　1.41　according　to　the　double　logarithmic　regression　method.　The　calculated　value　of　＂K＂　was　1862　M-1.　Fluorescence　emission　intensity　decreases　with　increasing　concentration　(30　mu　M-5000　mu　M).　The　detection　limit　of　the　synthesized　sensor　is　0.221　mu　M.　(C)　2019　Published　by　Elsevier　Ltd　on　behalf　of　The　editorial　office　of　Journal　of　Materials　Science　&　Technology.