Photocatalytic　selective　organic　transformation　in　water　using　visible　light　as　the　driving　force　represents　an　environmentally　benign　strategy　for　synthesis　of　fine　chemicals　under　the　framework　of　green　chemistry.　We　herein　report　the　photocatalytic　aerobic　oxidation　of　benzylic　alcohols　to　corresponding　aldehydes　with　high　selectivity　in　water　over　a　flower-like　Bi2WO6　semiconductor　using　oxygen　as　an　oxidant　under　visible　light　irradiation　and　mild　conditions.　A　collection　of　joint　techniques,　in　terms　of　electron　spin　resonance　(ESR)　spectra　and　controlled　experiments　using　radicals　scavengers,　have　been　employed　to　explain　the　origin　of　the　high　selectivity　for　oxidation　of　benzylic　alcohols　achieved　over　the　flower-like　Bi2WO6　photocatalyst　in　an　aqueous　phase.　The　possible　reaction　mechanism　for　photocatalytic　selective　oxidation　of　alcohols　over　Bi2WO6　has　also　been　discussed.　©　2014　The　Royal　Society　of　Chemistry.