This　study　demonstrated　a　dye-sensitized　TiO2-polyoxometalate　system　(denoted　TiO2-(PW12-TH)　8,　where　PW12　=　PW12O403　and　TH　=　thionine)　for　selective　oxidation　of　alcohols　under　visible　light.　The　results　showed　that　various　substituted　alcohols　were　transformed　into　their　corresponding　aldehydes　with　high　selectivity.　Due　to　more　efficient　electrons　transfer,　large　surface　area,　and　enhanced　visible　light　absorption,　the　photocatalytic　activity　of　TiO2-(PW12-TH)　8　was　superior　to　any　other　dyesensitized　system　reported　to　date.　The　response　in　the　photocurrent-time　curves　over　several　on/off　cycles　of　intermittent　irradiation　showed　good　reproducibility.　The　photocurrent　response　of　TiO2(PW12-TH)　8　was　much　higher　than　that　of　TiO2/TH　(physical　mixture　of　TiO2　and　TH),　SiO2-(PW12-TH)　8　or　P25-(PW12-TH)　8　(P25　=　Degussa　P25),　attributed　to　the　more　efficient　transfer　and　longer　lifetime　of　photoexcited　electrons.　This　photocatalytic　process　confirmed　that　efficient　electron　transfer　during　photocatalytic　oxidation　plays　a　vital　role　in　determining　the　reaction　conversion　and　obtaining　good　selectivity.　Electron　paramagnetic　resonance　(EPR)　spectra　and　radical　scavenging　experiments　proved　that　superoxide　radicals　and　electrons　were　the　main　reactive　species　in　the　proposed　system,　the　absence　of　hydroxyl　radicals　and　holes　is　demonstrated　to　be　the　key　of　high　reaction　selectivity.　(C)　2017　Elsevier　Inc.　All　rights　reserved.