The　effects　of　various　parameters　(co-solvents,　electron　acceptors,　and　surface　modification)　on　the　direct　synthesis　of　alpha-naphthol　from　naphthalene　using　photocatalytic　processes　were　investigated.　The　center　dot　OH　radicals　generated　on　UV-illuminated　TiO2　photocatalysts　led　to　the　direct　hydroxylation　of　naphthalene　to　alpha-naphthol.　The　addition　of　Fe3+,　Fe2+,　Fe3+　+　H2O2,　and　Fe2+　+　H2O2　greatly　increases　the　conversion　of　naphthalene　and　the　yield　of　alpha-naphthol　in　TiO2　suspensions.　The　addition　of　Fe3+　+　H2O2　to　a　TiO2　suspension　increased　the　yield　to　22.2%.　Surface　modified-TiO2　had　a　significant　influence　on　the　hydroxylation　reaction.　La-Eu/TiO2,　La-Y/TiO2,　H3PW12O40/TiO2,　H3PMo12O40/TiO2,　Fe/TiO2,　Ag/TiO2,　Cu/TiO2,　and　N/TiO2　enhanced　the　conversion　and　yield　more　than　TiO2.　Fe/TiO2　has　the　highest　photocatalytic　efficiency　among　these　species.