{"Article":[{"abstractInfo":"PhotocathodicprotectionbyTiO2<\/sub>semiconductormaterialsformetalshasinterestedmanycorrosionresearchersforyears.However,apureTiO2<\/sub>semiconductoranodecanonlyabsorbultravioletlightandcannotmaintainthephotocathodicprotectioninthedark.Thishaslimiteditspracticalapplicationstoagreatextent.Overcomingtheselimitationsissignificantaswellaschallenging.Therefore,theobjectiveofthisworkistoprepareamodifiedTiO2<\/sub>compositefilmwithvisiblelightabsorptionandchargestoragecapabilitiesforapplicationinphotocathodicprotection.First,wefabricatedanorderedTiO2<\/sub>nanotubearrayfilmonaTisubstratebyelectrochemicalanodization.Then,wepreparedNiOnanoparticlesonthefilmvia<\/i>ahydrothermalreactiontoobtainap<\/i>-n<\/i>heterostructuredNiO/TiO2<\/sub>nanotubearraycompositefilm.Thepropertiesofthepreparedfilmswereinvestigatedbyscanningelectronmicroscopy,X-raydiffraction,X-rayphotoelectronspectroscopy,UV-Visabsorptionspectroscopy,photoluminescencespectroscopy,andphotoelectrochemicaltechniques.TheresultsindicatedthattheelectrochemicallyanodizedTiO2<\/sub>filmhadananatasephasestructureandconsistedofverticallyorderednanotubeswithaninnerdiameterofabout80nmandlengthof250nm.AftertheNiOnanoparticlesweredepositedonthefilm,theTiO2<\/sub>nanotubearraystructureremainedintact.ThemainphaseofTiO2<\/sub>wasstillanatase,butthelightabsorptionoftheNiO/TiO2<\/sub>compositefilmwasextendedintothevisibleregion,whichwasincontrasttothatofthesimpleTiO2<\/sub>film.Moreover,thecompositefilmshowedlowerphotoluminescenceintensitiesthantheTiO2<\/sub>film,implyingthatahigherchargecarrierseparationefficiencycouldbeachievedbymodificationwithNiO.Underwhitelightillumination,thephotocurrentdensityoftheNiO/TiO2<\/sub>compositefilminamixedsolutionof0.5mol·L-1<\/sup>KOHand1mol·L-1<\/sup>CH3<\/sub>OHreached176μA·cm-2<\/sup>,whichwas2timeshigherthanthatofthesimpleTiO2<\/sub>nanotubefilm,indicatingthatthecompositefilmhadimprovedphotoelectricconversionefficiencyandphotoelectrochemicalproperties.Thepotentialof403stainlesssteel(403SS)in0.5mol·L-1<\/sup>NaClsolutiondecreasedby380and440mVrelativetoitscorrosionpotentialwhencoupledtotheTiO2<\/sub>filmandNiO/TiO2<\/sub>compositefilm,respectively,underwhitelightillumination.ThisindicatedthattheheterostructuredNiO/TiO2<\/sub>filmasaphotoanodecouldproducemoreeffectivephotocathodicprotectiononthesteelascomparedwiththepureTiO2<\/sub>film.Evenafter2.5hofillumination,thecompositefilmcouldcontinuouslyprovidephotocathodicprotectionto403SSforabout15.5hinthedark,suggestingthattheNiO/TiO2<\/sub>compositefilmhadachargestoragecapabilitythatwassignificantforitspracticalapplications.