Semiconductor　photocatalysis　has　received　much　attention　as　a　promising　technique　to　solve　energy　crisis　and　environmental　pollution.　This　work　demonstrated　the　rational　design　of　“sandwich”　WO　3　/rGO/SnIn　4　S　8　(WGS)　Z-scheme　photocatalysts　for　efficient　purification　of　wastewater　emitted　from　tannery　and　dyeing　industries.　Such　materials　were　prepared　by　a　combined　protocol　of　the　in　situ　precipitation　method　with　hydrothermal　synthesis,　and　structurally　characterized　by　XRD,　SEM,　HRTEM,　UV-vis　DRS,　and　PL　spectroscopy.　Results　showed　that　the　Z-schemed　nanohybrids　significantly　enhanced　the　photocatalytic　activity　compared　to　the　single　component　photocatalysts.　An　optimized　case　of　the　WGS-2.5%　photocatalysts　exhibited　the　highest　Cr(VI)　reduction　rate,　which　was　ca.　1.8　and　12　times　more　than　those　of　pure　SnIn　4　S　8　(SIS)　and　WO　3　,　respectively.　Moreover,　the　molecular　mechanism　of　the　enhanced　photocatalysis　was　clearly　revealed　by　the　radical-trapping　control　experiments　and　electron　paramagnetic　resonance　(ESR)　spectroscopy.　The　amount　of　superoxide　and　hydroxyl　radicals　as　the　major　reactive　oxygen　species　performing　the　redox　catalysis　was　enhanced　significantly　on　the　Z-scheme　WGS　photocatalysts,　where　the　spatial　separation　of　photoinduced　electron-hole　pairs　was　therefore　accelerated　for　the　reduction　of　Cr(VI)　and　degradation　of　Rhodamine　B　(RhB).　This　study　provides　a　novel　strategy　for　the　synthesis　of　all-solid-state　Z-scheme　photocatalysts　for　environmental　remediation.　©　2019　by　the　authors.　Licensee　MDPI,　Basel,　Switzerland.