BiOI　nanosheet　photocatalysts　with　different　Er3+　doping　contents　were　rapidly　synthesized　by　microwave-assisted　solvothermal　method　using　water　and　ethylene　glycol　as　a　mixed　solvent.　All　synthesized　photocatalysts　were　characterized　by　X-ray　diffraction　(XRD),　X-ray　photoelectron　spectroscopy　(XPS),　scanning　electron　microscopy　(SEM),　energy　dispersive　X-ray　spectroscopy　(EDX),　N-2　adsorption,　photoluminescence　(PL)　spectra,　and　UV-vis　diffuse　reflectance　spectroscopy　(DRS).　The　photocatalytic　activities　of　the　as-prepared　Er3+-doped　BiOI　nanosheets　were　investigated　by　the　photodegradation　of　Rhodamine　B　(RhB)　dye　in　aqueous　solution　under　visible　light　irradiation.　The　photodegradation　results　indicate　the　optimal　doping　of　1　mol.%　Er3+　in　BiOI　nanosheets　(doping　content　is　from　0　mol.%　to　4　mol.%)　to　be　the　most　beneficial　for　photodegradation　of　RhB.　1Er-BiOI　nanosheets　also　possesses　good　photocatalytic　activity　for　representative　anionic　methyl　orange　(MO).　From　the　scavenger　testing　results,　the　reactive　species　of　holes　(h(+))　and　superoxide　radical　anions　(O-center　dot(2-))　show　major　impacts　on　the　photodegradation　progress　of　RhB　and　MO　dyes　over　1Er-BiOI　photocatalyst　under　visible　light　irradiation.　(C)　2018　Published　by　Elsevier　B.V.　on　behalf　of　The　Society　of　Powder　Technology　Japan.　All　rights　reserved.