Synthesis and characterization of PMoV/Fe3O4/g-C3N4 from melamine: An industrial green nanocatalyst for deep oxidative desulfurization

Article abstract of DOI:10.1016/S1872-2067(16)62548-2

A facile approach to the preparation of a novel magnetically separable H₅PMo₁₀V₂O₄₀/Fe₃O₄/g-C₃N₄ (PMoV/Fe₃O₄/g-C₃N₄) nanocomposite by chemical impregnation is demonstrated. The prepared nanocomposite was characterized and its acidity was measured by potentiometric titration. PMoV/Fe₃O₄/g-C₃N₄ showed high catalytic activity in the selective oxidative desulfurization of sulfides to their corresponding sulfoxides or sulfones. The catalytic oxidation of a dibenzothiophene (DBT)-containing model oil and that of real oil were also studied under optimized conditions. In addition, the effects of various nitrogen compounds, as well as the use of one- and two-ring aromatic hydrocarbons as co-solvents, on the catalytic removal of sulfur from DBT were investigated. The catalyst was easily separated and could be recovered from the reaction mixture by using an external magnetic field. Additionally, the remaining reactants could be separated from the products by simple decantation if an appropriate solvent was chosen for the extraction. The advantages of this nanocatalyst are its high catalytic activity and reusability; it can be used at least four times without considerable loss of activity.

Full text of DOI:10.1016/S1872-2067(16)62548-2

ChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ458–468
ꢀ
ꢀ ꢀ ꢀ
ꢀ ꢀ ꢀ ꢀ
a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m
ꢀ
j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c h n j c
ꢀ
ꢀ
Article
SynthesisꢀandꢀcharacterizationꢀofꢀPMoV/Fe
3
O
4
/g‐C N4ꢀfromꢀ ꢀ
3
melamine:ꢀAnꢀindustrialꢀgreenꢀnanocatalystꢀforꢀdeepꢀoxidativeꢀ
desulfurizationꢀ
a,b,
a
EzzatꢀRafieeꢀ *,ꢀMaryamꢀKhodayariꢀ
ꢀ
aꢀFacultyꢀofꢀChemistry,ꢀRaziꢀUniversity,ꢀKermanshahꢀ67149,ꢀIranꢀ
bꢀInstituteꢀofꢀNanoꢀScienceꢀandꢀNanoꢀTechnology,ꢀRaziꢀUniversity,ꢀKermanshahꢀ67149,ꢀIranꢀ
A R T I C L E ꢀ I N F O ꢀ
A B S T R A C T ꢀ
Articleꢀhistory:ꢀ
AꢀfacileꢀapproachꢀtoꢀtheꢀpreparationꢀofꢀaꢀnovelꢀmagneticallyꢀseparableꢀH PMo10V O40/Fe O /g‐C N
5 2 3 4 3 4
Receivedꢀ17ꢀOctoberꢀ2016ꢀ
Acceptedꢀ25ꢀNovemberꢀ2016ꢀ
Publishedꢀ5ꢀMarchꢀ2017ꢀ
(PMoV/Fe
nanocompositeꢀ wasꢀ characterizedꢀ andꢀ itsꢀ acidityꢀ wasꢀ measuredꢀ byꢀ potentiometricꢀ titration.ꢀ
PMoV/Fe /g‐C ꢀshowedꢀhighꢀcatalyticꢀactivityꢀinꢀtheꢀselectiveꢀoxidativeꢀdesulfurizationꢀofꢀsul‐
fidesꢀtoꢀtheirꢀcorrespondingꢀsulfoxidesꢀorꢀsulfones.ꢀTheꢀcatalyticꢀoxidationꢀofꢀaꢀdibenzothiophene
DBT)‐containingꢀmodelꢀoilꢀandꢀthatꢀofꢀrealꢀoilꢀwereꢀalsoꢀstudiedꢀunderꢀoptimizedꢀconditions.ꢀInꢀ
3
O
4
/g‐C
3
N
4
)ꢀ nanocompositeꢀ byꢀ chemicalꢀ impregnationꢀ isꢀ demonstrated.ꢀ Theꢀ preparedꢀ
3
O
4
3
N
4
(
Keywords:ꢀ
addition,ꢀtheꢀeffectsꢀofꢀvariousꢀnitrogenꢀcompounds,ꢀasꢀwellꢀasꢀtheꢀuseꢀofꢀone‐ꢀandꢀtwo‐ringꢀaromaticꢀ
hydrocarbonsꢀasꢀco‐solvents,ꢀonꢀtheꢀcatalyticꢀremovalꢀofꢀsulfurꢀfromꢀDBTꢀwereꢀinvestigated.ꢀTheꢀ
catalystꢀwasꢀeasilyꢀseparatedꢀandꢀcouldꢀbeꢀrecoveredꢀfromꢀtheꢀreactionꢀmixtureꢀbyꢀusingꢀanꢀexternalꢀ
magneticꢀfield.ꢀAdditionally,ꢀtheꢀremainingꢀreactantsꢀcouldꢀbeꢀseparatedꢀfromꢀtheꢀproductsꢀbyꢀsim‐
pleꢀ decantationꢀ ifꢀ anꢀ appropriateꢀ solventꢀ wasꢀ chosenꢀ forꢀ theꢀ extraction.ꢀ Theꢀ advantagesꢀ ofꢀ thisꢀ
nanocatalystꢀareꢀitsꢀhighꢀcatalyticꢀactivityꢀandꢀreusability;ꢀitꢀcanꢀbeꢀusedꢀatꢀleastꢀfourꢀtimesꢀwithoutꢀ
considerableꢀlossꢀofꢀactivity.ꢀ
Graphiticꢀcarbonꢀnitrideꢀ
Nanocompositeꢀ
Melamineꢀ
Heteropolyꢀacidꢀ
Oxidativeꢀdesulfurizationꢀ
Oilꢀ
©ꢀ2016,ꢀDalianꢀInstituteꢀofꢀChemicalꢀPhysics,ꢀChineseꢀAcademyꢀofꢀSciences.
PublishedꢀbyꢀElsevierꢀB.V.ꢀAllꢀrightsꢀreserved.
1
.ꢀ ꢀ Introductionꢀ
(4,6‐DMDBT)ꢀ areꢀ oxidizedꢀ toꢀ theirꢀ correspondingꢀ sulfonesꢀ inꢀ
theꢀpresenceꢀofꢀanꢀoxidizingꢀagent,ꢀandꢀremovalꢀofꢀtheseꢀoxi‐
dizedꢀproductsꢀisꢀcarriedꢀoutꢀbyꢀextractionꢀorꢀadsorptionꢀpro‐
cessesꢀ[2,3].ꢀReportedꢀoxidativeꢀdesulfurizationꢀcatalystsꢀhaveꢀ
includedꢀionicꢀliquidsꢀ(ILs)ꢀ[4–9],ꢀcompositesꢀ[10,11],ꢀpolyox‐
ometalatesꢀ(POMs)ꢀ[12,13],ꢀorganicꢀacidsꢀ[14],ꢀFenton’sꢀreagentꢀ
[15],ꢀandꢀmolecularꢀsievesꢀ[16,17].ꢀCatalyticꢀprocessesꢀbasedꢀonꢀ
theseꢀsystemsꢀhaveꢀmanyꢀadvantagesꢀandꢀhaveꢀattractedꢀglobalꢀ
attention.ꢀ ILsꢀ canꢀ beꢀ usedꢀ asꢀ novelꢀ solventsꢀ forꢀ extraction,ꢀ
POM‐basedꢀ homogeneousꢀ catalystsꢀ showꢀ highꢀ performancesꢀ
underꢀmildꢀreactionꢀconditions,ꢀcompositesꢀareꢀeasilyꢀseparat‐
edꢀfromꢀtheꢀreactionꢀmixtureꢀandꢀshowꢀhighꢀreuseꢀcapabilities,ꢀ
andꢀorganicꢀacidsꢀandꢀFenton’sꢀreagentꢀdemonstrateꢀhighꢀreac‐
Researchꢀ onꢀ theꢀ desulfurizationꢀ ofꢀ fuelsꢀ andꢀ theꢀ technicalꢀ
importanceꢀ ofꢀ thisꢀ processꢀ forꢀ cleanꢀ energyꢀ productionꢀ andꢀ
removalꢀ ofꢀ environmentalꢀ pollutantsꢀ hasꢀ beenꢀ increasingꢀ inꢀ
recentꢀyears.ꢀDeepꢀdesulfurizationꢀofꢀdieselꢀfuelsꢀhasꢀattractedꢀaꢀ
lotꢀofꢀattentionꢀowingꢀtoꢀtheꢀincreasinglyꢀstringentꢀregulationsꢀ
andꢀfuelꢀspecificationsꢀforꢀtheꢀpurposesꢀofꢀenvironmentalꢀsafe‐
keepingꢀ inꢀ variousꢀ countriesꢀ [1].ꢀ Oxidativeꢀ desulfurizationꢀ
(ODS)ꢀisꢀconsideredꢀtoꢀbeꢀoneꢀofꢀtheꢀmostꢀpromisingꢀapproach‐
esꢀforꢀultra‐deepꢀdesulfurizationꢀofꢀdieselꢀfuel.ꢀInꢀtheꢀODSꢀpro‐
cess,ꢀ organosulfurꢀ compoundsꢀ suchꢀ asꢀ benzothiopheneꢀ (BT),ꢀ
dibenzothiopheneꢀ (DBT),ꢀ andꢀ 4,6‐dimethyldibenzothiopheneꢀ
*ꢀCorrespondingꢀauthor.ꢀTel/Fax:ꢀ+98‐833‐4274559;ꢀE‐mail:ꢀEzzat_rafiee@yahoo.comꢀ ꢀ
DOI:ꢀ10.1016/S1872‐2067(16)62548‐2ꢀ|ꢀhttp://www.sciencedirect.com/science/journal/18722067ꢀ|ꢀChin.ꢀJ.ꢀCatal.,ꢀVol.ꢀ38,ꢀNo.ꢀ3,ꢀMarchꢀ2017ꢀ ꢀ ꢀ

ꢀ
EzzatꢀRafieeꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ458–468ꢀ
459ꢀ
tionꢀratesꢀforꢀtheꢀremovalꢀofꢀsulfurꢀcontaining‐compoundsꢀfromꢀ
fuelꢀoils.ꢀ
Theꢀdesignꢀofꢀanꢀefficientꢀcatalystꢀforꢀthisꢀoxidationꢀprocessꢀ
isꢀchallenging.ꢀNanosizedꢀmetal–oxygenꢀclusterꢀanions,ꢀorꢀhet‐
eropolyꢀacidsꢀ(HPAs),ꢀformꢀaꢀclassꢀofꢀcompoundsꢀthatꢀisꢀuniqueꢀ
inꢀ itsꢀ structuralꢀ varietyꢀ andꢀ functionalꢀ versatilityꢀ [18].ꢀ Theseꢀ
2.1.ꢀ ꢀ Materialsꢀandꢀmethodsꢀ
FeCl ·6H Oꢀ (99%),ꢀ FeSO
3
2
4 2
·7H Oꢀ (99%),ꢀ NaOHꢀ (98%),ꢀ HClꢀ
(37%),ꢀmelamine,ꢀPMoVꢀ(>ꢀ99%),ꢀ andꢀallꢀotherꢀreagentsꢀ andꢀ
solventsꢀwereꢀobtainedꢀfromꢀMerck,ꢀAldrichꢀorꢀFlukaꢀandꢀwereꢀ
usedꢀ withoutꢀ furtherꢀ purification.ꢀ Transmissionꢀ electronꢀ mi‐
croscopyꢀ (TEM)ꢀ imagesꢀ wereꢀ obtainedꢀ withꢀ aꢀ transmissionꢀ
electronꢀmicroscopeꢀ(JeolꢀJEM‐2100ꢀwithꢀanꢀacceleratingꢀvolt‐
ageꢀofꢀ200ꢀkV).ꢀScanningꢀelectronꢀmicroscopyꢀ(SEM)ꢀwasꢀper‐
formedꢀ usingꢀ anꢀ AIS2300Cꢀ microscopeꢀ withꢀ scanningꢀ rangeꢀ
fromꢀ0ꢀtoꢀ20ꢀkeV.ꢀEnergy‐dispersiveꢀX‐rayꢀ(EDX)ꢀspectroscopyꢀ
measurementsꢀ wereꢀ recordedꢀ withꢀ anꢀ IXRFꢀ modelꢀ 550iꢀ at‐
tachedꢀtoꢀtheꢀscanningꢀelectronꢀmicroscope.ꢀSEM/EDXꢀsamplesꢀ
wereꢀpreparedꢀbyꢀcoatingꢀtheꢀsolidꢀparticlesꢀwithꢀaꢀconductiveꢀ
layer.ꢀX‐rayꢀdiffractionꢀ(XRD)ꢀpatternsꢀwereꢀobtainedꢀusingꢀaꢀ
STOEꢀpowderꢀdiffractionꢀsystem,ꢀ2θꢀdiffraction,ꢀandꢀaꢀscintilla‐
tionꢀcounterꢀdetector.ꢀElectrochemicalꢀexperimentsꢀwereꢀper‐
formedꢀ withꢀ aꢀ computer‐controlledꢀ Autolabꢀ modularꢀ electro‐
chemicalꢀ systemꢀ (Ecoꢀ Chemie,ꢀ Utrecht,ꢀ theꢀ Netherlands)ꢀ
equippedꢀ withꢀ GPESꢀ softwareꢀ (Ecoꢀ Chemie).ꢀ Inductivelyꢀ cou‐
pledꢀ plasmaꢀ atomicꢀ emissionꢀ spectroscopyꢀ (ICP‐AES)ꢀ onꢀ aꢀ
Spectroꢀ Cirosꢀ CCDꢀ spectrometerꢀ wasꢀ usedꢀ toꢀ investigateꢀ theꢀ
leachingꢀofꢀtheꢀactiveꢀsites.ꢀFourierꢀtransformꢀinfraredꢀ(FT‐IR)ꢀ
spectraꢀwereꢀacquiredꢀonꢀanꢀALPHAꢀFT‐IRꢀspectrometerꢀwithꢀ
samplesꢀasꢀKBrꢀpellets.ꢀMagneticꢀpropertiesꢀwereꢀdeterminedꢀ
usingꢀ aꢀ vibratingꢀ sampleꢀ magnetometerꢀ (BHV‐55,ꢀ Riken,ꢀ Ja‐
pan).ꢀUltraviolet‐visibleꢀ(UV‐vis)ꢀspectraꢀwereꢀmeasuredꢀusingꢀ
anꢀ Agilentꢀ (8453)ꢀ UV‐visꢀ diode‐arrayꢀ spectrometerꢀ inꢀ quartzꢀ
cellsꢀ withꢀ 1ꢀ cmꢀ opticalꢀ path.ꢀ Theꢀ potentialꢀ variationꢀ wasꢀ rec‐
ordedꢀusingꢀaꢀHannaꢀ302ꢀpHꢀmeterꢀandꢀaꢀdoubleꢀjunctionꢀelec‐
trode.ꢀNMRꢀspectraꢀwereꢀcarriedꢀoutꢀonꢀaꢀBrukerꢀAvanceꢀ200ꢀ
MHzꢀNMRꢀspectrometerꢀwithꢀTMSꢀasꢀtheꢀinternalꢀstandardꢀandꢀ
compounds,ꢀ whichꢀ consistꢀ ofꢀ O‐sharingꢀ MO ꢀpolyhedraꢀ(mostꢀ
x
VI
VI
V
oftenꢀMꢀ=ꢀMo ,ꢀW ꢀorꢀV ),ꢀhaveꢀfoundꢀapplicationsꢀinꢀvariousꢀ
fields.ꢀ Ofꢀ these,ꢀ theirꢀ catalyticꢀ applicationsꢀ areꢀ theꢀ mostꢀ im‐
portantꢀ [19–22].ꢀ Owingꢀ toꢀ theirꢀ uniqueꢀ metal–oxygenꢀ frame‐
workꢀ andꢀ reversibleꢀ electronꢀ transferꢀ abilitiesꢀ [23,24],ꢀ HPAsꢀ
haveꢀbeenꢀinvestigatedꢀextensivelyꢀasꢀcatalystsꢀforꢀaꢀvarietyꢀofꢀ
oxidationꢀreactions,ꢀincludingꢀepoxidationꢀandꢀdesulfurizationꢀ
[
25–27].ꢀH
5
PMo10
V O40ꢀ(PMoV)ꢀisꢀaꢀvanadium‐containingꢀHPA,ꢀ
2
whichꢀ isꢀ recognizedꢀ asꢀ anꢀ efficientꢀ homogeneousꢀ catalystꢀ be‐
causeꢀofꢀitsꢀbifunctionalꢀnatureꢀ(Brönstedꢀacidityꢀandꢀelectronꢀ
transferꢀ properties)ꢀ andꢀ easeꢀ ofꢀ modificationꢀ forꢀ acidicꢀ andꢀ
oxidativeꢀreactionsꢀ[28].ꢀImmobilizingꢀHPAsꢀontoꢀtheꢀsurfaceꢀofꢀ
aꢀsolidꢀsupportꢀisꢀnecessaryꢀtoꢀobtainꢀaꢀheterogeneousꢀcatalyst.ꢀ
Thisꢀ enhancesꢀ theirꢀ lowꢀ surfaceꢀ areaꢀ andꢀ reducesꢀ theirꢀ highꢀ
solubilityꢀinꢀpolarꢀmedia,ꢀthusꢀovercomingꢀsomeꢀofꢀtheꢀdifficul‐
tiesꢀ inꢀ catalystꢀ recovery.ꢀ Recently,ꢀ graphiticꢀ carbonꢀ nitrideꢀ
(g‐C
3
N ),ꢀtheꢀmostꢀstableꢀallotropeꢀofꢀcarbonꢀnitrideꢀ[29],ꢀhasꢀ
4
attractedꢀincreasingꢀattentionꢀasꢀaꢀconvenientꢀsupportꢀforꢀtheꢀ
immobilizationꢀofꢀHPAsꢀowingꢀtoꢀitsꢀenvironmentallyꢀfriendlyꢀ
properties,ꢀhighꢀchemicalꢀstability,ꢀreasonableꢀthermalꢀstability,ꢀ
low‐cost,ꢀ2Dꢀlayeredꢀstructure,ꢀandꢀtheꢀabundantꢀavailabilityꢀofꢀ
itsꢀ precursorsꢀ [30–32].ꢀ Anꢀ importantꢀ hindranceꢀ inꢀ theꢀ
large‐scaleꢀapplicationꢀofꢀnanosizedꢀcatalystsꢀisꢀtheꢀdifficultyꢀofꢀ
theirꢀseparationꢀfromꢀtheꢀreactionꢀmixtures.ꢀThisꢀisꢀdueꢀtoꢀpro‐
longedꢀ equipmentꢀ operation,ꢀ complicatedꢀ technicalꢀ require‐
ments,ꢀ andꢀ theꢀ highꢀ operationalꢀ costsꢀ ofꢀ classicalꢀ separationꢀ
methods.ꢀ However,ꢀ usingꢀ magneticꢀ nanoparticlesꢀ asꢀ specialꢀ
immobilizingꢀcarriersꢀforꢀtheꢀcatalystsꢀwouldꢀprovideꢀaꢀwayꢀtoꢀ
separateꢀ theꢀ nanocatalystsꢀ fromꢀ theꢀ reactionꢀ mixturesꢀ byꢀ
simplyꢀ usingꢀ anꢀ externalꢀ magneticꢀ fieldꢀ [33,34].ꢀ Therefore,ꢀ
preparationꢀ ofꢀ magneticallyꢀ separableꢀ nanocompositesꢀ basedꢀ
CDCl
ꢀasꢀsolvent.ꢀThinꢀlayerꢀchromatographyꢀonꢀprecoatedꢀsili‐
3
caꢀgelꢀ(fluorescentꢀatꢀ254ꢀnm,ꢀ0.2ꢀmm)ꢀonꢀaluminumꢀplatesꢀwasꢀ
usedꢀ toꢀ monitorꢀ theꢀ reactions.ꢀ Theꢀ totalꢀ sulfurꢀ contentꢀ wasꢀ
analyzedꢀ usingꢀ aꢀ multiꢀ EAꢀ 3100ꢀ Elementꢀ Analyzerꢀ (Analytikꢀ
JenaꢀAG).ꢀ
onꢀg‐C
3
N ꢀwouldꢀenableꢀtheirꢀeasyꢀseparationꢀfromꢀtheꢀsolutionꢀ
4
withꢀanꢀexternalꢀmagnet.ꢀHence,ꢀweꢀhaveꢀdevelopedꢀaꢀfacileꢀandꢀ
large‐scaleꢀmethodꢀforꢀtheꢀpreparationꢀofꢀaꢀnovelꢀmagneticallyꢀ
2.2.ꢀ ꢀ Preparationꢀofꢀtheꢀcatalystsꢀ
3 4 3 4
separableꢀ PMoV/Fe O /g‐C N ꢀ nanocompositeꢀ forꢀ theꢀ firstꢀ
2.2.1.ꢀ ꢀ Preparationꢀofꢀg‐C
3 4
N ꢀ
time.ꢀ Forꢀ thisꢀ purpose,ꢀ weꢀ firstꢀ preparedꢀ theꢀ Fe
3 4 3 4
O /g‐C N ꢀ
Pureꢀg‐C ꢀwasꢀfabricatedꢀbyꢀdirectlyꢀcalciningꢀmelamineꢀ
3 4
N
nanocompositeꢀ asꢀ aꢀ magneticallyꢀ separableꢀ support.ꢀ Then,ꢀ
PMoVꢀ wasꢀ immobilizedꢀ onꢀ thisꢀ magneticꢀ supportꢀ toꢀ giveꢀ theꢀ
inꢀair.ꢀBriefly,ꢀ2.0ꢀgꢀmelamineꢀwasꢀputꢀintoꢀanꢀaluminaꢀcrucibleꢀ
withꢀaꢀlooseꢀcoverꢀandꢀheatedꢀtoꢀ250ꢀ°Cꢀfromꢀroomꢀtempera‐
tureꢀinꢀaꢀmuffleꢀfurnaceꢀatꢀaꢀheatingꢀrateꢀofꢀ5ꢀ°C/min.ꢀTheꢀtem‐
peratureꢀwasꢀthenꢀraisedꢀtoꢀ550ꢀ°Cꢀwithꢀaꢀheatingꢀrateꢀofꢀ10ꢀ
°C/minꢀandꢀtheꢀsampleꢀwasꢀmaintainedꢀatꢀthisꢀtemperatureꢀforꢀ
PMoV/Fe
cessesꢀwereꢀachievedꢀusingꢀaꢀchemicalꢀco‐precipitationꢀmethod,ꢀ
andꢀtheꢀresultingꢀPMoV/Fe /g‐C ꢀcompositeꢀshowedꢀcon‐
3 4 3 4
O /g‐C N ꢀnanocomposite.ꢀTheseꢀtwoꢀsyntheticꢀpro‐
O
3 4
N
3 4
siderableꢀcatalyticꢀactivityꢀinꢀtheꢀselectiveꢀoxidationꢀofꢀorganicꢀ
sulfurꢀcompounds.ꢀInꢀaddition,ꢀtheꢀdesulfurizationꢀofꢀmodelꢀandꢀ
realꢀoilꢀwasꢀinvestigatedꢀinꢀtheꢀpresenceꢀofꢀtheꢀnewlyꢀsynthe‐
sizedꢀcatalystꢀunderꢀoptimizedꢀreactionꢀconditions.ꢀTheꢀprob‐
lemꢀ ofꢀ separatingꢀ theꢀ catalystꢀ fromꢀ theꢀ reactionꢀ mixtureꢀ wasꢀ
resolvedꢀbyꢀusingꢀthisꢀnovelꢀmagneticꢀnanocatalyst,ꢀandꢀexcel‐
lentꢀreusabilityꢀwithꢀalmostꢀnoꢀchangeꢀinꢀyieldꢀafterꢀfourꢀrunsꢀ
wasꢀobserved.ꢀ
anotherꢀ 2ꢀ h.ꢀ Finally,ꢀ theꢀ resultingꢀ yellowꢀ g‐C
cooledꢀtoꢀroomꢀtemperature.ꢀ
3
N ꢀ sampleꢀ wasꢀ
4
2.2.2.ꢀ ꢀ PreparationꢀofꢀtheꢀFe
TheꢀFe /g‐C ꢀnanocompositeꢀwasꢀpreparedꢀbyꢀchemicalꢀ
co‐precipitation.ꢀInꢀaꢀtypicalꢀsynthesis,ꢀ0.5ꢀgꢀg‐C ꢀwasꢀultra‐
sonicallyꢀdispersedꢀintoꢀ150ꢀmLꢀdistilledꢀwaterꢀforꢀ20ꢀminꢀatꢀ
roomꢀtemperature.ꢀThenꢀ0.58ꢀgꢀFeCl ·6H Oꢀwasꢀdissolvedꢀinꢀ25ꢀ
mLꢀdegassedꢀdistilledꢀwaterꢀ(solutionꢀA),ꢀandꢀ0.2ꢀgꢀFeSO ·7H Oꢀ
wasꢀ dissolvedꢀ inꢀ aꢀ solutionꢀ containingꢀ 10ꢀ mLꢀ distilledꢀ waterꢀ
3 4 3 4
O /g‐C N ꢀnanocompositeꢀ
O
3 4
N
3 4
N
3 4
3
2
4
2
2.ꢀ ꢀ Experimentalꢀ

460ꢀ
EzzatꢀRafieeꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ458–468ꢀ
andꢀ2ꢀmLꢀHClꢀ(2ꢀmol/L,ꢀsolutionꢀB).ꢀAfterwards,ꢀsolutionsꢀAꢀandꢀ
Bꢀ wereꢀ mixedꢀ underꢀ mechanicalꢀ stirringꢀ andꢀ nitrogenꢀ degas‐
tureꢀwasꢀstirredꢀatꢀ80ꢀ°C.ꢀTheꢀreactionꢀmixtureꢀwasꢀcooledꢀtoꢀ
roomꢀ temperatureꢀ andꢀ theꢀ catalystꢀ wasꢀ separatedꢀ usingꢀ anꢀ
externalꢀmagneticꢀ field.ꢀTheꢀ correspondingꢀ sulfonesꢀwereꢀ ex‐
tractedꢀwithꢀEtOHꢀfromꢀtheꢀreactionꢀmixtureꢀ(Methodꢀc,ꢀTableꢀ
2,ꢀentriesꢀ8–11).ꢀ
singꢀatꢀ60ꢀ°Cꢀtoꢀformꢀaꢀyellowꢀsuspensionꢀofꢀg‐C
3
N .ꢀAfterꢀstir‐
4
ringꢀ forꢀ 30ꢀ min,ꢀ anꢀ aqueousꢀ solutionꢀ ofꢀ ammoniaꢀ wasꢀ addedꢀ
untilꢀtheꢀ pHꢀreachedꢀ10.0.ꢀ Theꢀresultingꢀ darkꢀ brownꢀ suspen‐
sionꢀwasꢀthenꢀstirredꢀatꢀ80ꢀ°Cꢀforꢀanotherꢀ30ꢀmin.ꢀAfterꢀcoolingꢀ
toꢀroomꢀtemperature,ꢀtheꢀprecipitateꢀ wasꢀwashedꢀtwiceꢀwithꢀ
ethanolꢀandꢀdouble‐distilled,ꢀmagneticallyꢀseparatedꢀwater.ꢀTheꢀ
obtainedꢀdarkꢀbrownꢀprecipitateꢀwasꢀthenꢀdriedꢀinꢀanꢀovenꢀatꢀ
2.5.4.ꢀ ꢀ OxidativeꢀdesulfurizationꢀofꢀaꢀmodelꢀoilꢀcontainingꢀDBTꢀ
TheꢀODSꢀcatalyticꢀtestsꢀwereꢀperformedꢀbyꢀdissolvingꢀ5ꢀmLꢀ
ofꢀaꢀmodelꢀoilꢀcontainingꢀDBTꢀ(500,ꢀ800,ꢀ1000,ꢀ1200ꢀppm)ꢀinꢀaꢀ
mixedꢀsolventꢀofꢀEtOHꢀandꢀhexaneꢀ(1:1;ꢀv/vꢀratio).ꢀThen,ꢀ0.03ꢀgꢀ
60ꢀ°Cꢀforꢀ24ꢀh.ꢀ
ofꢀtheꢀcatalystꢀandꢀ30%ꢀH
2
O ꢀ(10ꢀmmol)ꢀaq.ꢀwasꢀaddedꢀtoꢀtheꢀ
2
2
.2.3.ꢀ ꢀ PreparationꢀofꢀtheꢀPMoV/Fe
ToꢀimmobilizeꢀtheꢀPMoVꢀonꢀtheꢀas‐preparedꢀFe
3
O
4
/g‐C
3
N
4
ꢀnanocompositeꢀ
mixture.ꢀTheꢀmixtureꢀwasꢀstirredꢀunderꢀairꢀ(atmosphericꢀpres‐
sure)ꢀinꢀaꢀflaskꢀequippedꢀwithꢀaꢀcondenserꢀatꢀ80ꢀ°C.ꢀAtꢀtheꢀendꢀ
ofꢀ theꢀ reaction,ꢀ theꢀ catalystꢀ wasꢀ separatedꢀ fromꢀ theꢀ reactionꢀ
mixtureꢀusingꢀanꢀexternalꢀmagnet,ꢀandꢀtheꢀcorrespondingꢀsul‐
foneꢀwasꢀextractedꢀwithꢀEtOH.ꢀ
3 4
O
/g‐C N ꢀ
3
4
supports,ꢀ0.7ꢀgꢀPMoVꢀwasꢀdissolvedꢀinꢀ5ꢀmLꢀdryꢀmethanol.ꢀThisꢀ
solutionꢀ wasꢀ addedꢀ dropwiseꢀ toꢀ aꢀ suspensionꢀ ofꢀ 1.0ꢀ gꢀ
Fe
sonication.ꢀTheꢀmixtureꢀwasꢀstirredꢀforꢀ24ꢀhꢀatꢀroomꢀtempera‐
tureꢀ toꢀ giveꢀ theꢀ PMoV/Fe /g‐C ꢀ nanocomposite.ꢀ Finally,ꢀ
3 4
O
/g‐C
3
N ꢀ inꢀ 50ꢀ mLꢀ methanolꢀ whileꢀ beingꢀ dispersedꢀ byꢀ
4
O
3 4
3
N
4
2.5.5.ꢀ ꢀ Effectꢀofꢀnitrogen‐containingꢀcompoundsꢀonꢀODSꢀ
theꢀobtainedꢀcatalystꢀwasꢀcollectedꢀusingꢀaꢀpermanentꢀmagnetꢀ
andꢀdriedꢀinꢀaꢀvacuumꢀovenꢀovernight.ꢀ
Theꢀoxidationꢀreactionꢀwasꢀcarriedꢀoutꢀbyꢀfirstꢀstirringꢀ5ꢀmLꢀ
ofꢀtheꢀmodelꢀoilꢀcontainingꢀ1000ꢀppmꢀofꢀDBTꢀinꢀaꢀmixedꢀsolventꢀ
ofꢀEtOHꢀandꢀhexaneꢀ(1:1;ꢀv/vꢀratio)ꢀatꢀ80ꢀ°C.ꢀThen,ꢀ0.03ꢀgꢀofꢀtheꢀ
2.3.ꢀ ꢀ Voltammetryꢀexperimentsꢀ
catalystꢀandꢀ30%ꢀH
2
O ꢀ(10ꢀmmol)ꢀaq.ꢀwereꢀaddedꢀtoꢀtheꢀmix‐
2
ture.ꢀ Toꢀ investigateꢀ theꢀ effectꢀ ofꢀ nitrogen‐containingꢀ com‐
poundsꢀonꢀtheꢀoxidationꢀofꢀDBT,ꢀindole,ꢀquinolone,ꢀpyridineꢀorꢀ
pyrrolꢀ(60ꢀppm)ꢀwereꢀaddedꢀtoꢀtheꢀmodelꢀoil.ꢀAfterꢀcompletionꢀ
ofꢀ theꢀ reaction,ꢀ theꢀ catalystꢀ wasꢀ separatedꢀ fromꢀ theꢀ reactionꢀ
mixtureꢀusingꢀanꢀexternalꢀmagnet.ꢀWhenꢀEtOHꢀwasꢀusedꢀasꢀtheꢀ
solventꢀ forꢀ extraction,ꢀ theꢀ productsꢀ couldꢀ beꢀ separatedꢀ fromꢀ
theꢀpolarꢀphaseꢀbyꢀsimpleꢀdecantation,ꢀwhichꢀprovidedꢀaꢀsimpleꢀ
wayꢀtoꢀseparateꢀtheꢀproductsꢀfromꢀtheꢀreactionꢀmixture.ꢀ
Electrochemicalꢀreductionꢀofꢀtheꢀsamplesꢀwasꢀperformedꢀinꢀ
phosphateꢀbufferꢀ(0.1ꢀmol/L,ꢀpHꢀ=ꢀ5)ꢀwithꢀAg/AgClꢀasꢀtheꢀref‐
erenceꢀ electrodeꢀ andꢀ glassyꢀ carbonꢀasꢀtheꢀworkingꢀelectrode.ꢀ
Cyclicꢀ voltammogramsꢀ ofꢀ theꢀ samplesꢀ (ν,ꢀ 0.1ꢀ V/s)ꢀ wereꢀ pre‐
paredꢀatꢀroomꢀtemperatureꢀ(20ꢀ±ꢀ5ꢀ°C).ꢀ
2
.4.ꢀ ꢀ Acidityꢀmeasurementꢀ
Forꢀ theꢀ potentiometricꢀ titration,ꢀ 0.05ꢀ gꢀ solidꢀ catalystꢀ wasꢀ
2.5.6.ꢀ ꢀ EffectꢀofꢀaromaticꢀhydrocarbonsꢀonꢀODSꢀ
addedꢀtoꢀ90ꢀmLꢀacetonitrileꢀandꢀmagneticallyꢀstirredꢀforꢀ3ꢀh.ꢀ
Theꢀ suspensionꢀ wasꢀ thenꢀ titratedꢀ withꢀ aꢀ solutionꢀ ofꢀ
n‐butylamineꢀ(0.05ꢀN)ꢀinꢀacetonitrile.ꢀ
Theꢀoxidationꢀreactionꢀwasꢀcarriedꢀoutꢀbyꢀfirstꢀstirringꢀ5ꢀmLꢀ
ofꢀtheꢀmodelꢀoilꢀcontainingꢀ1000ꢀppmꢀofꢀDBTꢀinꢀaꢀmixedꢀsolventꢀ
ofꢀEtOHꢀandꢀhexaneꢀ(1:1;ꢀv/vꢀratio)ꢀatꢀ80ꢀ°C.ꢀThen,ꢀ0.03ꢀgꢀofꢀtheꢀ
catalystꢀandꢀ30%ꢀH
2
O ꢀ(10ꢀmmol)ꢀaq.ꢀwasꢀaddedꢀtoꢀtheꢀmix‐
2
2
.5.ꢀ ꢀ Catalyticꢀreactionsꢀ
ture.ꢀ Theꢀ influenceꢀ ofꢀ one‐ringꢀ aromaticꢀ hydrocarbonsꢀ (tolu‐
ene,ꢀ xylene,ꢀ mesityleneꢀ orꢀ benzene)ꢀ andꢀ aꢀ two‐ringꢀ aromaticꢀ
hydrocarbonꢀ(naphthalene)ꢀonꢀtheꢀconversionꢀofꢀtheꢀmodelꢀoilꢀ
wasꢀinvestigatedꢀbyꢀadditionꢀofꢀ40%ꢀratioꢀ(v/v)ꢀofꢀtheseꢀaro‐
maticꢀ compoundsꢀ toꢀ theꢀ mixture.ꢀ Theꢀ catalystꢀ andꢀ productsꢀ
wereꢀseparatedꢀasꢀdescribedꢀabove.ꢀ
2.5.1.ꢀ ꢀ Oxidationꢀofꢀliquidꢀsulfidesꢀtoꢀsulfoxidesꢀ ꢀ
Aꢀmixtureꢀofꢀ0.01ꢀgꢀofꢀtheꢀcatalystꢀandꢀ30%ꢀH
2
O ꢀ(4ꢀmmol)ꢀ
2
aq.ꢀwasꢀaddedꢀtoꢀaꢀsolutionꢀofꢀtheꢀsulfideꢀ(1ꢀmmol)ꢀinꢀaꢀmixedꢀ
solventꢀofꢀEtOHꢀandꢀhexaneꢀ(1:1;ꢀ2ꢀmL),ꢀandꢀtheꢀresultingꢀmix‐
tureꢀwasꢀstirredꢀatꢀroomꢀtemperature.ꢀAtꢀtheꢀendꢀofꢀtheꢀreac‐
tion,ꢀ theꢀ catalystꢀ wasꢀ separatedꢀ usingꢀ anꢀ externalꢀ magneticꢀ
field.ꢀ Theꢀ correspondingꢀ sulfoxideꢀ wasꢀ thenꢀ extractedꢀ withꢀ
EtOHꢀfromꢀtheꢀreactionꢀmixtureꢀ(Methodꢀa,ꢀTableꢀ1).ꢀ
2.5.7.ꢀ ꢀ Oxidativeꢀdesulfurizationꢀofꢀrealꢀoilꢀ
ForꢀtheꢀODSꢀofꢀrealꢀoil,ꢀ5ꢀmLꢀofꢀoilꢀ(sulfurꢀcontent:ꢀ500,ꢀ1900ꢀ
ppm,ꢀAPIꢀ41.67)ꢀwasꢀused.ꢀFirst,ꢀ5ꢀmLꢀofꢀtheꢀoilꢀwasꢀstirredꢀinꢀaꢀ
mixedꢀ solventꢀ ofꢀ EtOHꢀ andꢀ hexaneꢀ (1:1;ꢀ v/vꢀ ratio)ꢀ atꢀ 80ꢀ °C.ꢀ
2.5.2.ꢀ ꢀ Oxidationꢀofꢀliquidꢀsulfidesꢀtoꢀsulfonesꢀ
Then,ꢀ0.03ꢀgꢀofꢀtheꢀcatalystꢀandꢀ30%ꢀH
2
O ꢀ(10ꢀmmol)ꢀaq.ꢀwereꢀ
2
Aꢀsimilarꢀmethodꢀtoꢀthatꢀdescribedꢀaboveꢀwasꢀutilizedꢀforꢀ
sulfoneꢀ synthesis,ꢀ butꢀ theꢀ reactionsꢀ wereꢀ performedꢀ inꢀ theꢀ
addedꢀtoꢀtheꢀmixtureꢀandꢀitꢀwasꢀheatedꢀatꢀ80ꢀ°Cꢀwithꢀvigorousꢀ
stirringꢀforꢀ200ꢀmin.ꢀAfterꢀcompletionꢀofꢀtheꢀreaction,ꢀtheꢀsolidꢀ
catalystꢀwasꢀseparatedꢀfromꢀtheꢀreactionꢀmixtureꢀusingꢀanꢀex‐
ternalꢀmagnet.ꢀWhenꢀEtOHꢀwasꢀusedꢀasꢀtheꢀsolventꢀforꢀextrac‐
tion,ꢀtheꢀproductsꢀcouldꢀbeꢀseparatedꢀfromꢀtheꢀpolarꢀphaseꢀbyꢀ
simpleꢀ decantation.ꢀ Theꢀ sulfurꢀ contentꢀ ofꢀ theꢀ realꢀ oilꢀ wasꢀ
measuredꢀusingꢀaꢀtotalꢀsulfurꢀanalyzer.ꢀ
presenceꢀofꢀ0.02ꢀgꢀofꢀtheꢀcatalystꢀandꢀputꢀaꢀblankꢀ30%H
2
O ꢀ(8ꢀ
2
mmol)ꢀaq.,ꢀandꢀatꢀ60ꢀ°Cꢀ(Methodꢀb,ꢀTableꢀ2,ꢀentriesꢀ1–7).ꢀ
2
.5.3.ꢀ ꢀ Oxidationꢀofꢀsolidꢀsulfurꢀcompoundsꢀtoꢀsulfonesꢀ ꢀ
Aꢀmixtureꢀofꢀ0.03ꢀgꢀofꢀtheꢀcatalystꢀandꢀ30%ꢀH ꢀ(10ꢀmmol)ꢀ
2 2
O
aq.ꢀwasꢀaddedꢀtoꢀaꢀsolutionꢀofꢀtheꢀsulfideꢀ(1ꢀmmol)ꢀinꢀaꢀmixedꢀ
solventꢀofꢀEtOHꢀandꢀhexaneꢀ(1:1;ꢀ2ꢀmL),ꢀandꢀtheꢀresultingꢀmix‐
2.5.8.ꢀ ꢀ Leachingꢀtestꢀ

ꢀ
EzzatꢀRafieeꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ458–468ꢀ
461ꢀ
Toꢀ investigateꢀ theꢀ leachingꢀ stabilityꢀ ofꢀ theꢀ
PMoV/Fe /g‐C ꢀnanocomposite,ꢀtheꢀcontentsꢀofꢀtheꢀPMoVꢀ
O
3 4
N
3 4
(1)
filtratesꢀ wereꢀ quantitativelyꢀ evaluatedꢀ byꢀ ICP‐AESꢀ afterꢀ com‐
pletionꢀofꢀtheꢀoxidationꢀreactionꢀofꢀmethylꢀphenylꢀsulfideꢀ(MPS,ꢀ
(2)
10ꢀmmol)ꢀinꢀaꢀmixedꢀsolventꢀofꢀEtOHꢀandꢀhexaneꢀ(1:1;ꢀ20ꢀmL)ꢀ
inꢀ theꢀ presenceꢀ ofꢀ 0.3ꢀ gꢀ ofꢀ theꢀ catalystꢀ andꢀ 30%ꢀ H
2
O ꢀ (100ꢀ
2
mmol)ꢀaq.ꢀ
3.ꢀ ꢀ Resultsꢀandꢀdiscussionꢀ
3.1.ꢀ ꢀ Catalystꢀpreparationꢀandꢀcharacterizationꢀ
TheꢀPMoV/Fe
theꢀ followingꢀ procedure.ꢀ First,ꢀ theꢀ g‐C
sonicallyꢀdispersedꢀinꢀwaterꢀandꢀthenꢀFeꢀsaltsꢀwereꢀadded.ꢀTheꢀ
Feꢀ ionsꢀ wereꢀ convertedꢀ intoꢀ Fe ꢀ nanoparticlesꢀ withꢀ con‐
trolledꢀ growthꢀinꢀtheꢀ presenceꢀ ofꢀammoniaꢀasꢀaꢀprecipitatingꢀ
agent.ꢀAsꢀaꢀresult,ꢀfinelyꢀdistributedꢀandꢀuniformꢀFe ꢀnano‐
particlesꢀwereꢀeffectivelyꢀdepositedꢀonꢀtheꢀsurfaceꢀofꢀtheꢀg‐C
sheetsꢀ toꢀ giveꢀ theꢀ Fe /g‐C ꢀ nanocomposite,ꢀ whichꢀ wasꢀ
3
O
4
/g‐C
3
N
4
ꢀnanocompositeꢀwasꢀfabricatedꢀbyꢀ
Applied field (Oe)
3 4
N ꢀ sheetsꢀ wereꢀ ultra‐
Fig.ꢀ 2.ꢀ Magnetizationꢀ curvesꢀ forꢀ Fe
3
O
4
/g‐C
3
N
4
ꢀ
(1)ꢀ and
PMoV/Fe
3
O
4
/g‐C
3
N ꢀ(2).ꢀ
4
O
3 4
tributedꢀ toꢀ theꢀ stretchingꢀ vibrationalꢀ modesꢀ ofꢀ theꢀ primaryꢀ
=NH)ꢀ andꢀ secondaryꢀ (–NH)ꢀ aminesꢀ onꢀ theꢀ g‐C ꢀ aromaticꢀ
ringsꢀ[36].ꢀFurthermore,ꢀtheꢀtwoꢀcharacteristicꢀpeaksꢀatꢀaroundꢀ
50ꢀandꢀ485ꢀcm ꢀareꢀassignedꢀtoꢀtheꢀstretchingꢀvibrationsꢀofꢀ
theꢀ Fe–Oꢀ bondꢀ [37].ꢀ Inꢀ theꢀ spectrumꢀ ofꢀ PMoV/Fe /g‐C ,ꢀ
theꢀ vibrationalꢀ modesꢀ ofꢀ PMoVꢀ atꢀ 1163,ꢀ 1038,ꢀ 944ꢀ andꢀ 854ꢀ
O
3 4
(
N
3 4
3 4
N ꢀ
3
O
4
N
3 4
−1
6
thenꢀusedꢀasꢀaꢀsupportꢀforꢀtheꢀimmobilizationꢀofꢀPMoV.ꢀTheꢀinꢀ
situꢀgrowthꢀmechanismꢀalsoꢀpreventedꢀtheꢀaggregationꢀofꢀtheꢀ
3
O
4
N
3 4
Fe
g‐C
theꢀinteractionsꢀbetweenꢀeitherꢀterminalꢀMo=Oꢀbondsꢀorꢀbridgeꢀ
Mo–O–MoꢀbondsꢀwithinꢀtheꢀKegginꢀunitsꢀandꢀtheꢀNH ꢀgroupsꢀ
onꢀ theꢀ edgeꢀ ofꢀ C ꢀ sheets.ꢀ Hydrogenꢀ bondingꢀ orꢀ acid–baseꢀ
3 4
O ꢀnanoparticles.ꢀTheꢀKegginꢀunitsꢀofꢀPMoVꢀconnectꢀtoꢀtheꢀ
−1
cm ꢀareꢀattributedꢀtoꢀP–O,ꢀMo=O
tively.ꢀTheꢀcharacteristicꢀbandsꢀforꢀFe
theꢀ sameꢀ wavenumbersꢀ inꢀ theꢀ spectrumꢀ ofꢀ
PMoV/Fe /g‐C ,ꢀ withꢀ aꢀ smallꢀ shiftꢀ correspondingꢀ toꢀ theꢀ
interactionꢀbetweenꢀtheꢀsupportꢀandꢀtheꢀPMoV.ꢀTheꢀcharacter‐
isticꢀFT‐IRꢀbandsꢀofꢀtheꢀrecoveredꢀPMoV/Fe /g‐C ꢀnano‐
a
,ꢀMo–O
b
ꢀandꢀMo–O
c
,ꢀrespec‐
3 4
N ꢀsheetsꢀbyꢀformingꢀcovalentꢀMo–O–Cꢀbondsꢀasꢀaꢀresultꢀofꢀ
3
O
4
/g‐C
N
3 4
ꢀareꢀfoundꢀatꢀ
2
3
O
4
N
3 4
N
3 4
interactionsꢀmayꢀalsoꢀplayꢀaꢀrole.ꢀ
O
3 4
N
3 4
Fig.ꢀ 1ꢀ illustratesꢀ theꢀ FT‐IRꢀ spectraꢀ ofꢀ Fe
3
O
4
/g‐C
/g‐C
,ꢀtheꢀbandsꢀinꢀ
theꢀrangeꢀofꢀ1200–1700ꢀcm ꢀcorrespondꢀtoꢀtheꢀstretchingꢀvi‐
brationsꢀofꢀtheꢀC–NꢀandꢀC=Nꢀbondsꢀinꢀtheꢀg‐C ꢀheterocyclesꢀ
35].ꢀ Theꢀ broadꢀ absorptionꢀ bandꢀ atꢀ 3000–3500ꢀ cm ꢀ isꢀ at‐
3
N
4
,ꢀ
compositeꢀ areꢀ similarꢀ toꢀ thoseꢀ ofꢀ theꢀ freshꢀ nanocomposite,ꢀ
whichꢀmeansꢀthatꢀtheꢀprincipalꢀstructureꢀofꢀtheꢀcatalystꢀisꢀre‐
tainedꢀafterꢀuse.ꢀ
3 4 3 4
PMoV/Fe O /g‐C N ꢀ andꢀ theꢀ recoveredꢀ PMoV/Fe
3
O
4
3
N ꢀ
4
nanocomposites.ꢀInꢀtheꢀspectrumꢀofꢀFe
3 4 3 4
O /g‐C N
−1
Plotsꢀofꢀtheꢀmagnetizationꢀversusꢀtheꢀappliedꢀexternalꢀmag‐
N
3 4
neticꢀ fieldꢀ forꢀ theꢀ as‐preparedꢀ Fe
PMoV/Fe /g‐C ꢀ magneticꢀ nanocompositesꢀ atꢀ roomꢀ tem‐
peratureꢀareꢀshownꢀinꢀFig.ꢀ2.ꢀTheꢀsaturatedꢀmagnetizationꢀval‐
uesꢀforꢀtheꢀFe /g‐C ꢀandꢀPMoV/Fe /g‐C ꢀnanocompo‐
3 4
O /g‐C
3
N ꢀ
4
andꢀ
−
1
[
3
O
4
N
3 4
3
O
4
3
N
4
3
O
4
N
3 4
sitesꢀareꢀaboutꢀ65ꢀandꢀ35ꢀemu/g,ꢀrespectively.ꢀThereꢀisꢀnoꢀhys‐
teresis,ꢀ whichꢀ suggestsꢀ thatꢀ thisꢀ magneticꢀ nanocatalystꢀ hasꢀ aꢀ
superparamagneticꢀ character.ꢀ Itꢀ isꢀ clearꢀ thatꢀ theꢀ saturatedꢀ
magnetizationꢀvalueꢀofꢀFe
enceꢀ ofꢀ PMoV,ꢀ thusꢀ confirmingꢀ theꢀ presenceꢀ ofꢀ nonmagneticꢀ
materialsꢀonꢀtheꢀsurfaceꢀofꢀtheꢀg‐C .ꢀ
Fig.ꢀ 3ꢀ illustratesꢀ theꢀ excellentꢀ andꢀ easyꢀ separationꢀ ofꢀ theꢀ
3 4 3 4
O /g‐C N ꢀwasꢀreducedꢀinꢀtheꢀpres‐
N
3 4
Fig.ꢀ 3.ꢀ Separationꢀ ofꢀ theꢀ PMoV/Fe
reactionꢀmixtureꢀusingꢀanꢀexternalꢀmagnet.ꢀ(a)ꢀatꢀtheꢀstartꢀofꢀtheꢀreac‐
tion;ꢀ(b)ꢀafterꢀcompletionꢀofꢀtheꢀreaction.ꢀ
3
O
4
/g‐C
3
N ꢀ nanocatalystꢀ fromꢀ theꢀ
4
Fig.ꢀ1.ꢀFT‐IRꢀspectraꢀofꢀFe
recoveredꢀPMoV/Fe /g‐C
3
O
4
/g‐C
ꢀ(3).ꢀ
3
N
4
ꢀ(1),ꢀPMoV/Fe
3
O
4
/g‐C
3
N ꢀ(2)ꢀandꢀ
4
3
O
4
3
N
4

462ꢀ
EzzatꢀRafieeꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ458–468ꢀ
4(b)ꢀ illustratesꢀ theꢀ cyclicꢀ voltammetryꢀ (CV)ꢀ responsesꢀ ofꢀ
PMoV/Fe
3
O
4
/g‐C
3
N
4ꢀandꢀFe
3
O
4
/g‐C
3
N ‐modifiedꢀ glassyꢀcarbonꢀ
4
electrodesꢀ inꢀ aꢀ phosphateꢀ bufferꢀ solutionꢀ atꢀ pHꢀ =ꢀ 5.ꢀ Inꢀ theꢀ
voltammogramꢀ ofꢀ Fe /g‐C ,ꢀ Fe ꢀ showsꢀ twoꢀ sharpꢀ andꢀ
O
3 4
N
3 4
O
3 4
well‐definedꢀ redoxꢀ wavesꢀ thatꢀ correspondꢀ toꢀ theꢀ reversibleꢀ
reduction/oxidationꢀ processesꢀ [40].ꢀ Aꢀ sharpꢀ cathodicꢀ peakꢀ atꢀ
aroundꢀ−0.28ꢀV,ꢀwhichꢀclearlyꢀcorrespondsꢀtoꢀtheꢀreductionꢀofꢀ
3
+
2+
Fe ꢀtoꢀFe ꢀ(Eq.ꢀ(1)),ꢀandꢀanꢀanodicꢀpeakꢀatꢀapproximatelyꢀ0.15ꢀ
V,ꢀ whichꢀ correspondsꢀ toꢀ theꢀ oxidationꢀ ofꢀ Fe ꢀbyꢀHPO
2−ꢀ (Eq.ꢀ
2+
4
(
2)),ꢀcouldꢀbeꢀdetected.ꢀ
–
+

2+
Fe
3
O
4
ꢀ+ꢀ2e ꢀ+ꢀ8H ꢀ  ꢀ 3Fe ꢀ+ꢀ4H
2
Oꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ (1)ꢀ
2
+
2– 
–
+
Fe ꢀ+ꢀHPO
4
ꢀ  ꢀ FePO
4
ꢀ+ꢀe ꢀ+ꢀH ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ (2)ꢀ
Twoꢀpairsꢀofꢀreversibleꢀredoxꢀpeaksꢀwereꢀobservedꢀinꢀtheꢀ
potentialꢀ rangeꢀ betweenꢀ Eꢀ =ꢀ −0.9ꢀ Vꢀ andꢀ Eꢀ =ꢀ 0.2ꢀ Vꢀ forꢀ theꢀ
PMoV/Fe /g‐C ‐modifiedꢀ electrodeꢀ [41].ꢀ Theseꢀ canꢀ beꢀ
attributedꢀtoꢀtheꢀelectron‐transferꢀreactionsꢀofꢀtheꢀMo /Mo ,ꢀ
O
3 4
N
3 4
5+
4+
4+
3+
Mo /Mo ꢀcouples,ꢀandꢀfurtherꢀconfirmꢀthatꢀtheꢀtwo‐electronꢀ
exchangeꢀisꢀaccompaniedꢀbyꢀtwoꢀprotonationꢀreactionsꢀinꢀtheꢀ
PMo10
V
2
O
405−ꢀheteropolyanionꢀreductionꢀprocess.ꢀTheꢀelectronꢀ
exchangeꢀ processꢀ canꢀ thereforeꢀ beꢀ assignedꢀ asꢀ followsꢀ (Eq.ꢀ
(
3)):ꢀ
5–
–
+

405–ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ ꢀ (3)ꢀ
/g‐C N4ꢀ withꢀ thatꢀ ofꢀ
PMo10
V
2
O
40 ꢀ+ꢀ2e ꢀ+ꢀ2H ꢀ  ꢀ H
Comparingꢀ theꢀ CVꢀ ofꢀ PMoV/Fe
/g‐C N ,ꢀ weꢀ canꢀ deduceꢀ thatꢀ theꢀ presenceꢀ ofꢀ theꢀ PMoVꢀ
2
PMo10
V O
2
3
O
4
3
Fe
O
3 4
3
4
speciesꢀ facilitatesꢀ theꢀ oxidationꢀ andꢀ reductionꢀ ofꢀ
PMoV/Fe
reaction.ꢀ
3
O
4
/g‐C
3
N ꢀ inꢀ catalyticꢀ cyclesꢀ ofꢀ theꢀ desulfurizationꢀ
4
E/V
Theꢀ morphologicalꢀ evolutionꢀ ofꢀ theꢀ as‐preparedꢀ
PMoV/Fe /g‐C ꢀnanocompositeꢀcanꢀbeꢀconfirmedꢀbyꢀSEMꢀ
andꢀTEMꢀobservation,ꢀasꢀpresentedꢀinꢀFig.ꢀ5.ꢀFig.ꢀ5(a)ꢀshowsꢀtheꢀ
TEMꢀ imageꢀ ofꢀ theꢀ PMoV/Fe /g‐C ꢀ nanocomposite.ꢀ Itꢀ isꢀ
clearꢀthatꢀsphericalꢀparticlesꢀofꢀFe ꢀandꢀPMoVꢀwithꢀaverageꢀ
diametersꢀofꢀaboutꢀ23ꢀnmꢀareꢀdepositedꢀonꢀtheꢀg‐C ꢀsheets.ꢀ
Microstructureꢀ measurementꢀ wasꢀ performedꢀ byꢀ measuringꢀ
particleꢀsizesꢀatꢀseveralꢀspotsꢀinꢀtheꢀTEMꢀimageꢀtoꢀobtainꢀaꢀhis‐
togramꢀofꢀtheꢀsizeꢀdistributionꢀofꢀtheꢀnanocompositeꢀparticles.ꢀ
Fig.ꢀ 4.ꢀ Potentiometricꢀ titrationꢀ curvesꢀ (a)ꢀ andꢀ cyclicꢀ voltammograms
b)ꢀofꢀFe /g‐C ꢀandꢀPMoV/Fe /g‐C .ꢀ
O
3 4
N
3 4
(
O
3 4
N
3 4
O
3 4
N
3 4
magneticꢀ nanocatalystꢀ fromꢀ theꢀ solutionꢀ usingꢀ anꢀ externalꢀ
magnet.ꢀ Itꢀ canꢀ thusꢀ beꢀ concludedꢀ thatꢀ magnetizationꢀ ofꢀ theꢀ
O
3 4
3 4
N
3 4
O
PMoV/Fe
callyꢀseparateꢀtheꢀnanocatalystꢀfromꢀtheꢀreactionꢀsolution.ꢀ
InvestigationꢀofꢀtheꢀacidityꢀofꢀPMoV/Fe /g‐C ꢀwasꢀper‐
formedꢀ byꢀ potentiometricꢀ titrationꢀ withꢀ n‐butylamineꢀ (Fig.ꢀ
(a)).ꢀTheꢀnatureꢀofꢀtheꢀsupportꢀandꢀtheꢀtypeꢀofꢀHPAꢀareꢀbe‐
3 4 3 4
O /g‐C N ꢀ nanocompositeꢀ isꢀ sufficientꢀ toꢀ magneti‐
N
3 4
O
3 4
N
3 4
4
DepositionꢀofꢀtheꢀFe
sheetsꢀ wasꢀ alsoꢀ confirmedꢀ byꢀ theꢀ SEMꢀ imageꢀ ofꢀ theꢀ
PMoV/Fe /g‐C ꢀnanocompositeꢀ(Fig.ꢀ5(b)).ꢀ
3 4
O
ꢀandꢀPMoVꢀnanoparticlesꢀonꢀtheꢀg‐C
N ꢀ
3 4
lievedꢀ toꢀ affectꢀ theꢀ acidityꢀ ofꢀ theꢀ supportedꢀ HPA.ꢀ Theꢀ initialꢀ
electrodeꢀpotentialꢀ(Ei)ꢀdemonstratesꢀtheꢀmaximumꢀstrengthꢀofꢀ
theꢀ acidꢀ sites.ꢀ Inꢀ addition,ꢀ theꢀ valueꢀ atꢀ whichꢀ theꢀ plateauꢀ isꢀ
reachedꢀ(mmolꢀamine/gꢀsolid,ꢀn)ꢀindicatesꢀtheꢀtotalꢀnumberꢀofꢀ
acidꢀsitesꢀthatꢀareꢀpresentꢀinꢀtheꢀtitratedꢀsolidsꢀ[38].ꢀTheꢀacidicꢀ
strengthꢀofꢀtheꢀacidꢀsitesꢀisꢀclassifiedꢀaccordingꢀtoꢀtheꢀfollowingꢀ
scale:ꢀ Eiꢀ>ꢀ100ꢀ mVꢀ(veryꢀ strongꢀacidꢀ sites),ꢀ0ꢀ <ꢀEiꢀ <ꢀ 100ꢀ mVꢀ
O
3 4
N
3 4
Theꢀcrystalꢀstructuresꢀofꢀtheꢀsamplesꢀwereꢀinvestigatedꢀus‐
ingꢀpowderꢀXRDꢀdiffractionꢀpatterns.ꢀFig.ꢀ6(a)ꢀshowsꢀtheꢀtypicalꢀ
XRDꢀ patternsꢀ ofꢀ theꢀ as‐preparedꢀ Fe
O /g‐C N ,ꢀ
3 4 3 4
PMoV/Fe /g‐C andꢀ recoveredꢀ PMoV/Fe
3
O
4
3
N
4
ꢀ
O /g‐C N ꢀ
3 4 3 4
nanocomposites.ꢀTheꢀstrongꢀpeakꢀatꢀ27.41°ꢀcorrespondsꢀtoꢀtheꢀ
characteristicꢀinter‐planarꢀstackingꢀofꢀtheꢀconjugatedꢀaromaticꢀ
(
−
strongꢀacidꢀsites),ꢀ−100ꢀ<ꢀEiꢀ<ꢀ0ꢀmVꢀ(weakꢀacidꢀsites)ꢀandꢀEiꢀ<ꢀ
100ꢀmVꢀ(veryꢀweakꢀacidꢀsites)ꢀ[39].ꢀAccordingꢀtoꢀthisꢀscale,ꢀ
theꢀPMoV/Fe
/g‐C ꢀmagneticꢀcatalystꢀpresentsꢀveryꢀstrongꢀ
acidꢀ sitesꢀ (Eiꢀ =ꢀ 204ꢀ mV),ꢀ whereasꢀ Fe /g‐C ꢀ presentsꢀ
systemsꢀ andꢀtheꢀinter‐layerꢀ structuralꢀ packingꢀofꢀg‐C
Peaksꢀareꢀobservedꢀatꢀ2θꢀ=ꢀ30.2°,ꢀ35.5°,ꢀ43.2°,ꢀ53.4°,ꢀ57.3°ꢀandꢀ
62.6°ꢀforꢀtheꢀFe ꢀcrystalꢀphaseꢀ[43].ꢀTheꢀPMoV/Fe /g‐C
3 4
N ꢀ[42].ꢀ
O
3 4
N
3 4
O
3 4
N
3 4
O
3 4
O
3 4
3 4
N ꢀ
weakerꢀacidꢀsitesꢀ(Eiꢀ=ꢀ63ꢀmV).ꢀImmobilizationꢀofꢀPMoVꢀonꢀtheꢀ
supportꢀledꢀtoꢀanꢀincreaseꢀinꢀbothꢀtheꢀacidꢀstrengthꢀ(Ei)ꢀandꢀtheꢀ
totalꢀnumberꢀofꢀacidꢀsitesꢀ(n)ꢀdueꢀtoꢀtheꢀdispersionꢀofꢀtheꢀPMoVꢀ
anionsꢀ onꢀ theꢀ support.ꢀ Asꢀ aꢀ bifunctionalꢀ catalyst,ꢀ
containsꢀtheꢀimportantꢀcharacteristicꢀpeaksꢀofꢀpureꢀPMoVꢀ(atꢀ
2θꢀ=ꢀ12.5°ꢀandꢀ25.5°).ꢀTheꢀpresenceꢀofꢀtheseꢀpeaksꢀconfirmsꢀourꢀ
FT‐IRꢀspectroscopicꢀresults,ꢀwhichꢀsuggestedꢀthatꢀthereꢀwasꢀnoꢀ
significantꢀvariationꢀinꢀtheꢀstructureꢀofꢀPMoVꢀduringꢀtheꢀprep‐
PMoV/Fe
3 4
O
/g‐C N
3 4
ꢀprovidesꢀtwoꢀdifferentꢀproperties,ꢀnamelyꢀ
arationꢀ ofꢀ theꢀ nanocatalyst.ꢀ Whenꢀ theꢀ PMoV/Fe
nanocompositeꢀwasꢀrecovered,ꢀtheꢀdiffractionꢀpatternꢀwasꢀsim‐
ilarꢀtoꢀthatꢀofꢀfreshꢀPMoV/Fe /g‐C .ꢀThisꢀlackꢀofꢀchangeꢀinꢀ
3
O
4
/g‐C
3
N ꢀ
4
Brönstedꢀ acidityꢀ andꢀ electronꢀ transferꢀ properties.ꢀ Toꢀ investi‐
gateꢀtheꢀelectronꢀtransferꢀbehaviorꢀofꢀPMoV/Fe
3 4 3 4
O /g‐C N ,ꢀweꢀ
O
3 4
N
3 4
studiedꢀ
PMoV/Fe
theꢀ
/g‐C
electrochemicalꢀ
ꢀ andꢀ Fe /g‐C
behaviorꢀ
N ꢀ nanocomposites.ꢀ Fig.ꢀ
4
ofꢀ
theꢀ
theꢀ diffractionꢀ patternꢀ confirmsꢀthatꢀtheꢀstructureꢀisꢀ retainedꢀ
evenꢀafterꢀrecoveryꢀandꢀreuse.ꢀ
3
O
4
N
3 4
3
O
4
3

ꢀ
EzzatꢀRafieeꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ458–468ꢀ
463ꢀ
Fig.ꢀ5.ꢀTEMꢀimageꢀwithꢀparticleꢀsizeꢀdistributionꢀhistogramꢀ(a)ꢀandꢀSEMꢀimagesꢀofꢀtheꢀPMoV/Fe
3
O
4
/g‐C
3
N ꢀnanocatalystꢀ(b).ꢀ
4
TheꢀcompositionsꢀofꢀtheꢀPMoV/Fe
3
O
4
/g‐C
3
N
4
ꢀandꢀrecoveredꢀ
analysisꢀ (Fig.ꢀ 6ꢀ (b),ꢀ andꢀ (c)).ꢀ Theꢀ peaksꢀ ofꢀ theꢀ as‐preparedꢀ
nanocompositeꢀclearlyꢀcorrespondꢀtoꢀC,ꢀFeꢀandꢀMoꢀwithꢀmolarꢀ
ratiosꢀ ofꢀ 9.13%,ꢀ 21.01%ꢀ andꢀ 47.12%ꢀ respectively.ꢀ Therefore,ꢀ
similarlyꢀ toꢀ theꢀ resultsꢀ obtainedꢀ fromꢀ theꢀ XRDꢀ patterns,ꢀ EDXꢀ
PMoV/Fe /g‐C ꢀnanocompositesꢀwereꢀdeterminedꢀbyꢀEDXꢀ
O
3 4
N
3 4
alsoꢀconfirmsꢀthatꢀparticlesꢀofꢀFe
3
O
4
ꢀandꢀPMoVꢀwereꢀanchoredꢀ
ꢀ sheets.ꢀ Theꢀ EDXꢀ analysisꢀ ofꢀ theꢀ recoveredꢀ
/g‐C ꢀ nanocompositeꢀ isꢀ presentedꢀ inꢀ Fig.ꢀ 6(c).ꢀ
,ꢀPMoVꢀandꢀtheꢀg‐C ꢀsheetsꢀasꢀconstit‐
uentsꢀ ofꢀ theꢀ PMoV/Fe /g‐C ꢀ nanocompositeꢀ afterꢀ reuseꢀ
onꢀ theꢀ g‐C N
3 4
PMoV/Fe O
3 4
N
3 4
TheꢀpresenceꢀofꢀFe
O
3 4
N
3 4
O
3 4
N
3 4
wasꢀconfirmedꢀwithꢀEDXꢀanalysis.ꢀMoreover,ꢀtheꢀmolarꢀratiosꢀofꢀ
C,ꢀFeꢀandꢀMoꢀwereꢀ10.3%,ꢀ23.2%ꢀandꢀ40.1%,ꢀrespectively.ꢀTheꢀ
decreaseꢀinꢀtheꢀpercentageꢀofꢀMoꢀcouldꢀbeꢀdueꢀtoꢀleachingꢀofꢀ
theꢀinitialꢀPMoVꢀcontentꢀintoꢀtheꢀreactionꢀmixture.ꢀ
3.2.ꢀ ꢀ Catalyticꢀreactionsꢀ
Theꢀactivityꢀofꢀtheꢀmagneticꢀnanocatalystꢀwasꢀdemonstratedꢀ
byꢀoxidationꢀofꢀvariousꢀsulfidesꢀtoꢀtheꢀcorrespondingꢀsulfoxidesꢀ
andꢀsulfonesꢀinꢀtheꢀpresenceꢀofꢀhydrogenꢀperoxideꢀasꢀanꢀoxi‐
dant.ꢀTheꢀinfluenceꢀofꢀdifferentꢀreactionꢀparameters,ꢀincludingꢀ
theꢀ solventꢀ system,ꢀ amountꢀ ofꢀ catalystꢀ andꢀ H
2
O /MPSꢀ (O/S)ꢀ
2
molarꢀ ratioꢀ wasꢀ evaluatedꢀ forꢀ aꢀ modelꢀ system,ꢀ theꢀ selectiveꢀ
oxidationꢀ ofꢀ MPSꢀ toꢀ methylꢀ phenylꢀ sulfoxideꢀ (MPSO)ꢀ inꢀ theꢀ
presenceꢀofꢀPMoV/Fe
3
O
4
/g‐C
3
N ꢀ(Schemeꢀ1,ꢀFig.ꢀ7),ꢀtoꢀstudyꢀtheꢀ
4
variousꢀ factorsꢀ affectingꢀ theꢀ selectivityꢀ andꢀ efficiencyꢀ ofꢀ theꢀ
catalyst.ꢀFirst,ꢀtheꢀeffectꢀofꢀtheꢀsolventꢀsystemꢀonꢀtheꢀproductꢀ
conversionꢀwasꢀinvestigatedꢀ (Fig.ꢀ 7(a)).ꢀ Theꢀ resultsꢀ indicatedꢀ
thatꢀtheꢀuseꢀofꢀaꢀnon‐polarꢀsolvent,ꢀsuchꢀasꢀhexane,ꢀwasꢀunfa‐
vorableꢀ forꢀ thisꢀ conversion.ꢀ Theꢀ bestꢀ conversionꢀ dataꢀ wereꢀ
foundꢀinꢀtheꢀpresenceꢀofꢀMeCNꢀandꢀEtOH:ꢀhexane.ꢀTheꢀbiphasicꢀ
solventꢀsystemꢀEtOH/hexaneꢀwasꢀselectedꢀasꢀtheꢀbestꢀsolventꢀ
systemꢀforꢀtwoꢀreasons.ꢀFirst,ꢀethanolꢀisꢀtheꢀmostꢀsuitableꢀsol‐
ventꢀ forꢀ extractionꢀ becauseꢀ itꢀ isꢀ derivedꢀ fromꢀ agriculturalꢀ
O
O
O
S
S
S
3 4 3 4
PMoV/Fe O /g-C N
+
Fig.ꢀ6.ꢀ(a)ꢀXRDꢀpatternsꢀofꢀFe
coveredꢀ PMoV/Fe /g‐C
ꢀ(b)ꢀ andꢀ recoveredꢀPMoV/Fe
3
O
N ꢀ
4
/g‐C
nanocatalysts.ꢀ EDXꢀ spectraꢀ of
/g‐C ꢀ nanocata‐
3
N
4
,ꢀPMoV/Fe
3
O
4
/g‐C
3
N
4
,ꢀandꢀre‐
2 2
H O
O
3 4
3
4
MPS
MPSO
MPSO
2
PMoV/Fe
lystsꢀ(c).ꢀ
3
O
4
/g‐C N
3 4
3
O
4
3
N
4
Schemeꢀ1.ꢀModelꢀreaction.ꢀ

464ꢀ
EzzatꢀRafieeꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ458–468ꢀ
Fig.ꢀ8.ꢀReusabilityꢀofꢀPMoV/Fe
theꢀconditionsꢀforꢀmethodꢀa).ꢀ
3
O
4
/g‐C
3
N ꢀinꢀtheꢀmodelꢀreactionꢀ(underꢀ
4
fourthꢀrunꢀ(90%ꢀyieldꢀofꢀMPSOꢀafterꢀ20ꢀmin).ꢀ ꢀ
Toꢀ understandꢀ theꢀ reasonꢀ forꢀ theꢀ lowerꢀ rateꢀ ofꢀ sulfurꢀ re‐
movalꢀwhenꢀusingꢀtheꢀrecycledꢀcatalyst,ꢀleachingꢀofꢀtheꢀactiveꢀ
siteꢀinꢀtheꢀmodelꢀreactionꢀwasꢀstudiedꢀbyꢀICP‐AES.ꢀTheꢀresultsꢀ
showꢀ thatꢀ 12%ꢀ ofꢀ theꢀ initialꢀ PMoVꢀ contentꢀ leachedꢀ intoꢀ theꢀ
reactionꢀmixtureꢀoverꢀfourꢀsuccessiveꢀruns,ꢀandꢀthisꢀwasꢀcon‐
firmedꢀbyꢀEDXꢀanalysis.ꢀ
TheꢀresultsꢀfromꢀtheꢀacidityꢀandꢀCVꢀmeasurementsꢀshownꢀinꢀ
Fig.ꢀ4(b)ꢀsuggestꢀthatꢀtheꢀcatalystꢀcanꢀcatalyzeꢀtheꢀreactionꢀviaꢀ
twoꢀdifferentꢀpathways,ꢀthroughꢀitsꢀBrӧnstedꢀacidꢀandꢀelectronꢀ
transferꢀabilities.ꢀ
WeꢀattemptedꢀtoꢀselectivelyꢀproduceꢀsulfoneꢀMPSO
mainꢀ productꢀ byꢀ increasingꢀ theꢀ temperatureꢀ toꢀ 60ꢀ °Cꢀ (Fig.ꢀ
(a));ꢀhowever,ꢀselectivityꢀwasꢀnotꢀachievedꢀwithoutꢀincreasingꢀ
theꢀ O/Sꢀ ratio.ꢀ Whenꢀ theꢀ O/Sꢀ ratioꢀ wasꢀ increasedꢀ toꢀ 8:1,ꢀ theꢀ
yieldꢀofꢀMPSO ꢀwasꢀalsoꢀincreasedꢀ(Fig.ꢀ9(b)).ꢀInꢀaddition,ꢀin‐
2
ꢀasꢀtheꢀ
9
2
creasingꢀtheꢀcatalystꢀquantityꢀfromꢀ0.01ꢀtoꢀ0.02ꢀgꢀalsoꢀledꢀtoꢀanꢀ
increaseꢀinꢀ theꢀ selectivityꢀofꢀtheꢀreactionꢀ(95%ꢀ selectivityꢀ forꢀ
O/S ratio
MPSO )ꢀ(Fig.ꢀ9(c)).ꢀ
2
Fig.ꢀ 7.ꢀ Effectꢀ ofꢀ (a)ꢀ solventꢀ (1ꢀ mmolꢀ MPS,ꢀ O/Sꢀ ratioꢀ =ꢀ 4:1,ꢀ catalyst
amountꢀ=ꢀ0.01ꢀg,ꢀroomꢀtemperature),ꢀ(b)ꢀcatalystꢀamountꢀ(O/Sꢀratioꢀ=ꢀ
Encouragedꢀ byꢀ theseꢀ results;ꢀ weꢀ subjectedꢀ aꢀ seriesꢀ ofꢀ sul‐
fidesꢀtoꢀoxidationꢀunderꢀtheꢀoptimizedꢀconditionsꢀforꢀsulfoxideꢀ
orꢀsulfoneꢀformationꢀ(Tablesꢀ1ꢀandꢀ2).ꢀTheꢀexperimentalꢀresultsꢀ
showꢀthatꢀvariousꢀtypesꢀofꢀliquidꢀsulfidesꢀcouldꢀbeꢀoxidizedꢀtoꢀ
theꢀcorrespondingꢀsulfoxidesꢀwithꢀexcellentꢀselectivitiesꢀ(Tableꢀ
4
:1,ꢀreactionꢀtimeꢀ=ꢀ10ꢀmin,ꢀroomꢀtemperature),ꢀandꢀ(c)ꢀmolarꢀratioꢀofꢀ
/MPsꢀcatalystꢀamountꢀ=ꢀ0.01ꢀg,ꢀreactionꢀtimeꢀ=ꢀ10ꢀmin,ꢀroomꢀtem‐
perature)ꢀonꢀtheꢀselectiveꢀoxidationꢀofꢀMPSꢀtoꢀMPSOꢀinꢀtheꢀpresenceꢀof
PMoV/Fe /g‐C .ꢀ
H O
2 2
O
3 4
N
3 4
1).ꢀ ꢀ
productsꢀandꢀisꢀrenewable,ꢀbiologicallyꢀlessꢀobjectionableꢀinꢀtheꢀ
environmentꢀ andꢀ lessꢀ toxicꢀ thanꢀ acetonitrile.ꢀ Second,ꢀ asꢀ aꢀ
non‐polarꢀsolventꢀwithꢀaꢀtextureꢀsimilarꢀtoꢀthatꢀofꢀtheꢀmodelꢀoil,ꢀ
hexaneꢀ holdsꢀ promiseꢀ forꢀ applicationꢀ inꢀ theꢀ ODSꢀ process.ꢀ Asꢀ
shownꢀinꢀFig.ꢀ7(b),ꢀtheꢀquantityꢀofꢀtheꢀcatalystꢀusedꢀforꢀtheꢀoxi‐
dationꢀ ofꢀ MPSꢀ toꢀ MPSOꢀ wasꢀ optimized.ꢀ Whenꢀ 0.01ꢀ gꢀ ofꢀ theꢀ
nanocatalystꢀwasꢀused,ꢀMPSOꢀwasꢀobtainedꢀinꢀhighꢀyields.ꢀDe‐
creasingꢀtheꢀamountꢀofꢀcatalystꢀtoꢀ0.005ꢀgꢀresultedꢀinꢀaꢀlowerꢀ
conversion.ꢀCatalystꢀquantitiesꢀaboveꢀ0.01ꢀgꢀledꢀtoꢀlowerꢀselec‐
tivityꢀforꢀMPSO.ꢀTheꢀeffectꢀofꢀtheꢀO/Sꢀratioꢀwasꢀalsoꢀinvestigatedꢀ
Weꢀalsoꢀtestedꢀtheꢀreactionsꢀofꢀvariousꢀliquidꢀandꢀsolidꢀsul‐
fidesꢀatꢀ60ꢀandꢀ80ꢀ°CꢀandꢀwithꢀO/Sꢀratioꢀ=ꢀ8:1ꢀandꢀ10:1,ꢀrespec‐
tively.ꢀTheꢀobtainedꢀresultsꢀshowꢀthatꢀvariousꢀtypesꢀofꢀsulfidesꢀ
couldꢀbeꢀoxidizedꢀintoꢀtheirꢀcorrespondingꢀsulfonesꢀwithꢀexcel‐
lentꢀselectivitiesꢀ(Tableꢀ2).ꢀ
Basedꢀonꢀtheꢀaboveꢀresults,ꢀtheꢀPMoV/Fe
3
O
4
/g‐C
3
N ꢀnano‐
4
compositeꢀwasꢀusedꢀinꢀtheꢀODSꢀreactionꢀforꢀaꢀmodelꢀoilꢀcon‐
tainingꢀ DBT,ꢀ oneꢀ ofꢀ theꢀ majorꢀ sulfur‐containingꢀ compoundsꢀ
presentꢀinꢀfuels.ꢀModelꢀoilsꢀwithꢀvariousꢀsulfurꢀconcentrationsꢀ
wereꢀused,ꢀandꢀtheꢀreactionꢀwasꢀcarriedꢀoutꢀinꢀ5ꢀmLꢀofꢀaꢀmixedꢀ
(Fig.ꢀ7(c)).ꢀAtꢀanꢀO/Sꢀratioꢀofꢀ3:1,ꢀtheꢀyieldꢀofꢀMPSOꢀwasꢀlow,ꢀbutꢀ
solventꢀofꢀEtOHꢀandꢀhexaneꢀ(Fig.ꢀ10).ꢀTheꢀPMoV/Fe
O /g‐C N ꢀ
3 4 3 4
whenꢀtheꢀratioꢀwasꢀincreasedꢀtoꢀ4:1ꢀtheꢀyieldꢀincreasedꢀtoꢀ95%ꢀ
withꢀ 96.9%ꢀ selectivity.ꢀ Furtherꢀ increasesꢀ inꢀ theꢀ O/Sꢀ ratioꢀ (toꢀ
nanocompositeꢀ catalystꢀ efficientlyꢀ oxidizedꢀ theꢀ modelꢀ
DBT‐containingꢀ oilsꢀ withꢀ sulfurꢀ concentrationsꢀ ofꢀ upꢀ toꢀ 1000ꢀ
ppm.ꢀAꢀconcentrationꢀofꢀ1000ꢀppmꢀDBTꢀwasꢀselectedꢀforꢀfur‐
therꢀexperiments.ꢀ
6:1ꢀandꢀ8:1)ꢀresultedꢀinꢀaꢀlowerꢀselectivityꢀforꢀMPSO.ꢀThus,ꢀO/Sꢀ
ꢀ4:1ꢀwasꢀchosenꢀasꢀtheꢀoptimizedꢀratioꢀforꢀMPSOꢀproduction.ꢀ
=
Finally,ꢀtheꢀreusabilityꢀofꢀPMoV/Fe
usingꢀtheꢀconditionsꢀforꢀmethodꢀaꢀ(seeꢀtheꢀExperimentalꢀsec‐
tion)ꢀ(Fig.ꢀ8),ꢀandꢀexcellentꢀyieldsꢀwereꢀstillꢀobtainedꢀafterꢀtheꢀ
3
O
4
/g‐C
3
N
4
ꢀwasꢀinvestigatedꢀ
Itꢀ isꢀ acceptedꢀ thatꢀ nitrogen‐containingꢀ compoundsꢀ haveꢀ aꢀ
negativeꢀeffectꢀonꢀtheꢀODSꢀprocess.ꢀToꢀclarifyꢀtheꢀeffectsꢀofꢀni‐
trogen‐containingꢀcompounds,ꢀweꢀinvestigatedꢀtheꢀbehaviorꢀofꢀ

ꢀ
EzzatꢀRafieeꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ458–468ꢀ
Tableꢀ1ꢀ
465ꢀ
Selectiveꢀ oxidationꢀ ofꢀ liquidꢀ sulfidesꢀ toꢀ sulfoxidesꢀ withꢀ 30%ꢀ H
2 2
O ꢀaq.ꢀ
usingꢀFe
3
O
4
/g‐C
3
N /PMoVꢀasꢀaꢀcatalystꢀ*.ꢀ
4
O
S
O
R
O
S
Fe O
3 4
/g-C
3
N
4
/PMoV
S
R
R'
H O
2
R
R'
R'
2
ꢀ
Timeꢀ
Isolatedꢀyieldꢀ(%)ꢀ
Entry
Sulfideꢀ
(min)ꢀ
Sulfoxideꢀ
95ꢀ
Sulfoneꢀ
1ꢀ
2ꢀ
3ꢀ
S
10ꢀ
3ꢀ
2ꢀ
5ꢀ
Ph
ꢀ 5ꢀ
96ꢀ
10ꢀ
90ꢀ
4ꢀ
5ꢀ
10ꢀ
25ꢀ
94ꢀ
90ꢀ
2ꢀ
7ꢀ
S
Ph
Ph
S
6ꢀ
Phꢀ
35ꢀ
90ꢀ
5ꢀ
*ꢀMethodꢀa.ꢀ
ꢀ
Tableꢀ2ꢀ
Selectiveꢀ oxidationꢀ ofꢀ sulfidesꢀ toꢀ sulfonesꢀ withꢀ 30%ꢀ H
2
O ꢀ aq.ꢀ usingꢀ
2
PMoV/Fe
3
O
4
/g‐C
3
N ꢀasꢀaꢀcatalyst.ꢀ
4
O
S
O
R
O
Fe O /g-C N /PMoV
S
S
3
4
3 4
R
R'
H O
R
R'
R'
2
2
Timeꢀ Isolatedꢀyieldꢀ(%)
min)ꢀ Sulfoxide Sulfone
Entryꢀ Method
Sulfideꢀ
(
1ꢀ
bꢀ
S
ꢀ 10ꢀ
3ꢀ
95ꢀ
Ph
ꢀ
2ꢀ
3ꢀ
4ꢀ
5ꢀ
6ꢀ
bꢀ
bꢀ
bꢀ
bꢀ
bꢀ
ꢀ ꢀ 5ꢀ
ꢀ 10ꢀ
ꢀ ꢀ 5ꢀ
ꢀ 30ꢀ
ꢀ 45ꢀ
6ꢀ
4ꢀ
3ꢀ
7ꢀ
8ꢀ
92ꢀ
94ꢀ
95ꢀ
91ꢀ
90ꢀ
ꢀ
ꢀ
ꢀ
S
Ph
Ph
S
Ph
7ꢀ
bꢀ
ꢀ 50ꢀ
7ꢀ
90ꢀ
Fig.ꢀ9.ꢀEffectꢀofꢀ(a)ꢀtemperatureꢀ(catalystꢀamountꢀ=ꢀ0.01ꢀg,ꢀO/Sꢀratioꢀ=ꢀ
Ph
8
ꢀ
cꢀ
cꢀ
ꢀ 60ꢀ
ꢀ 65ꢀ
5ꢀ
6ꢀ
90ꢀ
92ꢀ
Ph
Ph
S
ꢀ
4
0
=
:1,ꢀreactionꢀtimeꢀ=ꢀ10ꢀmin),ꢀ(b)ꢀmolarꢀratioꢀofꢀH
.01ꢀg,ꢀreactionꢀtimeꢀ=ꢀ10ꢀmin,ꢀ60ꢀ°C)ꢀandꢀ(c)ꢀcatalystꢀamountꢀ(O/Sꢀratioꢀ
ꢀ4:1,ꢀreactionꢀtimeꢀ=ꢀ10ꢀmin,ꢀ60ꢀ°C)ꢀinꢀtheꢀselectiveꢀoxidationꢀofꢀMPSꢀto
2
O ꢀ(catalystꢀamountꢀ=
2
9ꢀ
S
Ph
ꢀ
ꢀ
1
0ꢀ
cꢀ
ꢀ 70ꢀ
2ꢀ
93ꢀ
MPSO .ꢀ
2
ꢀ
quinoline,ꢀindole,ꢀpyridineꢀandꢀpyrroleꢀinꢀtheꢀoxidationꢀsystemꢀ
Fig.ꢀ11(a)).ꢀTheꢀnitrogen‐containingꢀcompoundsꢀwereꢀoxidizedꢀ
toꢀtheꢀcorrespondingꢀproductsꢀinꢀshortꢀreactionꢀtimesꢀ(aboutꢀ
0ꢀmin).ꢀTheꢀreactionꢀrateꢀforꢀtheꢀoxidationꢀofꢀDBTꢀinꢀtheꢀpres‐
1ꢀ
1
cꢀ
ꢀ 65ꢀ
120ꢀ
4ꢀ
5ꢀ
90ꢀ
50ꢀ
(
12ꢀ
—ꢀ
2
S
enceꢀofꢀtheseꢀnitrogen‐containingꢀcompoundsꢀdecreasedꢀinꢀtheꢀ
order:ꢀindoleꢀ>ꢀquinolineꢀ>ꢀpyrrole > pyridine.ꢀTheseꢀresultsꢀ
thusꢀsuggestꢀthatꢀnitrogen‐containingꢀcompoundsꢀhaveꢀaꢀnega‐
tiveꢀeffectꢀonꢀtheꢀODSꢀprocessꢀowingꢀtoꢀcompetitionꢀwithꢀtheꢀ
sulfidesꢀ forꢀ adsorptionꢀ onꢀ theꢀ catalyticꢀ sites,ꢀ asꢀ wellꢀ asꢀ theirꢀ
basicꢀ character.ꢀ However,ꢀ thisꢀ negativeꢀ effectꢀ isꢀ minimal.ꢀ Toꢀ
verifyꢀtheꢀeffectꢀofꢀco‐solventsꢀonꢀtheꢀreaction,ꢀODSꢀofꢀtheꢀmod‐
elꢀ oilꢀ wasꢀ carriedꢀ outꢀ usingꢀ variousꢀ one‐ringꢀ aromaticꢀ com‐
poundsꢀ (toluene,ꢀ xylene,ꢀ mesityleneꢀ andꢀ benzene)ꢀ andꢀ theꢀ
two‐ringꢀ aromaticꢀ hydrocarbonꢀ naphthaleneꢀ asꢀ co‐solventsꢀ
underꢀ optimizedꢀ reactionꢀ conditionsꢀ (40%ꢀ v/vꢀ ratioꢀ ofꢀ
co‐solventꢀ toꢀ mixture)ꢀ (Fig.ꢀ 11(b)).ꢀ Theꢀ one‐ringꢀ aromaticꢀ
compoundsꢀhadꢀaꢀpositiveꢀeffectꢀonꢀODSꢀconversion.ꢀ ꢀ
S
13ꢀ
—ꢀ
120ꢀ
5ꢀ
45ꢀ
ꢀ
TheꢀreactionꢀrateꢀforꢀtheꢀoxidationꢀofꢀDBTꢀdecreasedꢀinꢀtheꢀ
orderꢀtolueneꢀ>ꢀxyleneꢀ>ꢀbenzeneꢀ> mesitylene,ꢀinꢀagreementꢀ
withꢀ theꢀ increasingꢀ stericꢀ hindranceꢀ inꢀ theseꢀ compounds.ꢀ Itꢀ
shouldꢀbeꢀnotedꢀthatꢀtheꢀtwo‐ringꢀ aromaticꢀ compoundꢀnaph‐
thaleneꢀhadꢀaꢀnegativeꢀeffectꢀonꢀtheꢀODSꢀreactionꢀandꢀreducedꢀ
theꢀreactionꢀrate.ꢀThisꢀnegativeꢀeffectꢀisꢀattributedꢀtoꢀtheꢀgreat‐
erꢀstericꢀhindranceꢀfromꢀtheꢀtwoꢀaromaticꢀrings.ꢀ
Theꢀ activityꢀ ofꢀ theꢀ PMoV/Fe
theꢀpresenceꢀofꢀH ꢀwasꢀevaluatedꢀinꢀtheꢀODSꢀofꢀrealꢀoil.ꢀUnderꢀ
optimumꢀ conditions,ꢀ 24.3%ꢀ andꢀ 29.8%ꢀ ofꢀ theꢀ sulfurꢀ wasꢀ re‐
O
3 4
3
/g‐C N
4
ꢀ nanocompositeꢀ inꢀ
O
2 2

466ꢀ
EzzatꢀRafieeꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ458–468ꢀ
H
O
H
2
O
2
2
H O
O
O
OH
O
O
O
O
5
-
2 40
PMo10V O
M
M
1
O
2
(M = Mo or V)
O
O
S
S
O
O
O
O
S
M
3
4
Schemeꢀ 2.ꢀ Proposedꢀ mechanismꢀ forꢀ theꢀ ODSꢀ reactionꢀ withꢀ aꢀ
PMoV/Fe /g‐C ꢀcatalystꢀinꢀtheꢀpresenceꢀofꢀH .ꢀ
O
3 4
N
3 4
O
2 2
Fig.ꢀ10.ꢀEffectꢀofꢀdibenzothiopheneꢀconcentrationꢀonꢀtheꢀODSꢀreaction
ofꢀdibenzothiopheneꢀ(underꢀtheꢀconditionsꢀofꢀmethodꢀc).ꢀ
behaviorꢀandꢀmagneticꢀpropertiesꢀofꢀtheꢀnanocompositeꢀwereꢀ
investigatedꢀusingꢀXRD,ꢀFT‐IRꢀspectroscopy,ꢀEDXꢀspectroscopy,ꢀ
SEM,ꢀ TEM,ꢀ CV,ꢀ ICP‐AESꢀ andꢀ vibratingꢀ sampleꢀ magnetometryꢀ
techniques.ꢀTheꢀnanocompositeꢀcatalystꢀshowedꢀhighꢀcatalyticꢀ
activityꢀandꢀgoodꢀselectivityꢀforꢀtheꢀoxidationꢀofꢀsulfidesꢀtoꢀtheꢀ
correspondingꢀsulfoxidesꢀorꢀsulfonesꢀunderꢀmildꢀreactionꢀcon‐
ditions.ꢀThisꢀcatalystꢀalsoꢀshowedꢀexcellentꢀactivityꢀinꢀtheꢀre‐
movalꢀofꢀsulfurꢀfromꢀDBT‐containingꢀmodelꢀoilꢀandꢀfromꢀrealꢀoilꢀ
containingꢀ500ꢀandꢀ1900ꢀppmꢀofꢀsulfurꢀcompounds.ꢀTheꢀeffectꢀ
ofꢀ quinoline,ꢀ indole,ꢀ pyridineꢀ andꢀ pyrroleꢀ asꢀ nitro‐
gen‐containingꢀ compoundsꢀ onꢀ ODSꢀ activityꢀ wasꢀ alsoꢀ investi‐
gated.ꢀ Inꢀ theꢀ presenceꢀ ofꢀ theseꢀ compounds,ꢀ theꢀ overallꢀ ODSꢀ
activityꢀ wasꢀ slightlyꢀ reducedꢀ owingꢀ toꢀ competitiveꢀ oxidationꢀ
betweenꢀtheꢀsulfur‐ꢀandꢀnitrogen‐containingꢀcompounds.ꢀNev‐
ertheless,ꢀthisꢀnegativeꢀeffectꢀwasꢀlow.ꢀTheꢀadditionꢀofꢀaromaticꢀ
co‐solventsꢀ suchꢀ asꢀ toluene,ꢀ xylene,ꢀ benzene, mesityleneꢀ orꢀ
naphthaleneꢀonꢀtheꢀODSꢀreactionꢀwasꢀalsoꢀinvestigated.ꢀMostꢀ
importantly,ꢀtheꢀPMoV/Fe
3
O
4
/g‐C
3
N ꢀnanocompositeꢀcouldꢀbeꢀ
4
recoveredꢀusingꢀanꢀappliedꢀmagneticꢀfieldꢀandꢀreusedꢀwithoutꢀ
significantꢀ lossꢀ ofꢀ catalyticꢀ activityꢀ evenꢀ afterꢀ fourꢀ successiveꢀ
cycles.ꢀ Therefore,ꢀ thisꢀ nanocompositeꢀ canꢀ beꢀ consideredꢀ aꢀ
promisingꢀcatalyticꢀmaterialꢀforꢀenvironmentalꢀapplications.ꢀ
Fig.ꢀ11.ꢀ(a)ꢀComparisonꢀofꢀtheꢀODSꢀreactionꢀofꢀDBTꢀinꢀtheꢀpresenceꢀof
differentꢀ nitrogen‐containingꢀ compoundsꢀ (DBTꢀ concentrationꢀ =ꢀ 1000
ppm,ꢀnitrogen‐containingꢀcompoundꢀconcentrationꢀ=ꢀ60ꢀppm,ꢀmethod
c);ꢀ(b)ꢀODSꢀreactionꢀofꢀDBTꢀinꢀtheꢀpresenceꢀofꢀvariousꢀaromaticꢀcom‐
poundsꢀ (40%ꢀ v/v)ꢀ asꢀ co‐solventꢀ (DBTꢀ concentrationꢀ =ꢀ 1000ꢀ ppm,
methodꢀc).ꢀ
Acknowledgmentsꢀ
TheꢀauthorsꢀthankꢀtheꢀRaziꢀUniversityꢀResearchꢀCouncilꢀforꢀ
supportꢀofꢀthisꢀwork.ꢀ
movedꢀfromꢀrealꢀoilꢀwithꢀsulfurꢀcontentsꢀofꢀ500ꢀandꢀ1900ꢀppm,ꢀ
respectively.ꢀ
Referencesꢀ
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Schemeꢀ2.ꢀTheꢀcatalyticꢀbehaviorꢀofꢀpolyoxometallicꢀanionsꢀhasꢀ
previouslyꢀ beenꢀ demonstratedꢀ [44–47].ꢀ Inꢀ theꢀ firstꢀ step,ꢀ
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[
PMo10V
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405−ꢀinꢀtheꢀPMoV/Fe
3 4 3 4
O O /g‐C N ꢀcatalystꢀisꢀoxidizedꢀbyꢀ
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generatedꢀ andꢀ theꢀ originalꢀ stateꢀofꢀtheꢀcatalystꢀisꢀrestoredꢀinꢀ
finalꢀstepꢀ(stepꢀ4).ꢀ
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[
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4.ꢀ ꢀ Conclusionsꢀ
Inꢀ summary,ꢀ aꢀ PMoV/Fe
3
O
4
/g‐C
3
N ꢀ nanocompositeꢀ hasꢀ
4
beenꢀ successfullyꢀ preparedꢀ byꢀ aꢀ simple,ꢀ effectiveꢀ andꢀ repro‐
ducibleꢀ method.ꢀ Theꢀ structure,ꢀ morphology,ꢀ electrochemicalꢀ
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Jiang,ꢀW.ꢀJiang,ꢀS.ꢀH.ꢀXun,ꢀChem.ꢀEng.ꢀJ.,ꢀ2013,ꢀ229,ꢀ250–256.ꢀ

ꢀ
EzzatꢀRafieeꢀetꢀal.ꢀ/ꢀChineseꢀJournalꢀofꢀCatalysisꢀ38ꢀ(2017)ꢀ458–468ꢀ
GraphicalꢀAbstractꢀ
467ꢀ
Chin.ꢀJ.ꢀCatal.,ꢀ2017,ꢀ38:ꢀ458–468ꢀ ꢀ ꢀ doi:ꢀ10.1016/S1872‐2067(16)62548‐2
3 4 3
SynthesisꢀandꢀcharacterizationꢀofꢀPMoV/Fe O /g‐C N4ꢀfromꢀmelamine:ꢀAnꢀindustrialꢀgreenꢀnanocatalystꢀforꢀdeepꢀoxidativeꢀ
desulfurizationꢀ
EzzatꢀRafieeꢀ*,ꢀMaryamꢀKhodayariꢀ ꢀ
RaziꢀUniversity,ꢀIranꢀ
ꢀ
ꢀ
H PMo10
5
V
2
O
40ꢀwasꢀsupportedꢀonꢀaꢀFe
3
O
4
/g‐C
3
N
4
ꢀmagneticꢀsupportꢀtoꢀproduceꢀaꢀPMoV/Fe
3
O
4
/g‐C
3
N ꢀnanocomposite.ꢀThisꢀcatalystꢀwasꢀ
4
characterizedꢀandꢀusedꢀforꢀselectiveꢀoxidativeꢀdesulfurizationꢀofꢀsulfides.ꢀOxidationꢀofꢀdibenzothiophene‐containingꢀmodelꢀoilsꢀandꢀrealꢀ
oilꢀwasꢀalsoꢀstudiedꢀunderꢀoptimizedꢀreactionꢀconditions.ꢀMoreover,ꢀtheꢀeffectsꢀofꢀvariousꢀnitrogen‐containingꢀcompoundsꢀandꢀaromaticꢀ
hydrocarbonsꢀonꢀdibenzothiopheneꢀremovalꢀwereꢀinvestigated.ꢀ
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