Photoreduction　of　4-nitroaniline　to　p-phenylenediamine　over　TiO2,　ZnO,　PbBi2Nb2O9　and　CdS　photocatalysts　in　the　presence　of　CH3OH　was　investigated　under　light　irradiation　(hv　＞=　band　gap)　upon　purging　with　N-2.　Compared　with　PbBi2Nb2O9　and　CdS,TiO2　and　ZnO　showed　photocatalytic　activities　for　the　photoreduction　of　4-nitroaniline.　Electron　spin　resonance　analysis　results　revealed　that　a　methanol　radical　could　be　detected　in　the　present　of　TiO2　and　ZnO.　Its　formation　was　attributed　to　the　reaction　between　the　hydroxyl　radical　and　CH3OH　molecule.　The　species　had　strong　reductive　ability,　and　therefore　could　reduce　4-nitroaniline　to　p-phenylenediamine.　Other　alcohols　(C2H5OH　and　i-C3H7OH)　were　also　found　to　be　efficient　additives　for　the　photoreduction　of　4-nitroaniline.　The　results　of　the　H-2-labeled　experiments　indicated　that　the　p-phenylenediamine　formation　was　formed　by　the　hydrogen　transfer　reaction　between　the　4-nitroaniline　and　H2O　molecules.　A　mechanism　was　proposed　to　explain　the　photoreduction　of　4-nitroaniline　to　p-phenylenediamine　in　the　present　alcohols.　(c)　2012　Elsevier　B.V.　All　rights　reserved.