The normalizedMnK-edgeandFeK-edgeXANESspectraand
their first derivativeoftheallcompositenanofibers areshownin
Figs. 5 and 6, respectively.TheadvantagesofXANESarethatitis
sensitivetothelocalenvironmentaroundtheprobingatomsand
consequentlyusedtoidentifythechemicalspeciesandoxidation
statesoftheprobingatoms.Asobviouslyseenin Fig. 5, forall
composite samples,theedgeenergiesofMnK-edgeandFeK-edge
werefoundat6559.05eVand7127.21eV(lessthan1eVerror),
respectively.TheedgeenergiesofMnK-edgeofallsampleslay
betweenbetweenMnO(Mn2þ) andMn2O3 (Mn3þ) standard
samples suggestinganexistenceofacouplingofMnoxidation
statesinallcompositesamples(Mn2þ/Mn3þ). MovingtoFe
K-edge,theedgeenergyvaluesareconsistentwiththeedgeen-
ergy ofFe2O3 (Fe3þ) standardsamplessuggestingthatFeatomsin
all sampleshavetheoxidationstatesof3þ. Thesesuchvalence
statesareagreedwiththeMnFe2O4 spinel structure.However,
these XANESresultscannotexactlyanswerthestructureof
MnFe2O4 spinel structureeithernormalspinelstructure,A2þ[Tet](
B2
3þ)[Oct]O4, orinversespinelstructure,B3þ[Tet]( A2þB3þ)[Oct]O4,
especiallylocalstructureofMnatomswhichexhibitamixed
oxidationstateof2þ and 3þ, respectively.Thesecanberevealed
using EXAFSresults.
normalizedMnK-edgeandFeK-edgeXANESspectraand
derivativeoftheallcompositenanofibers แรกของพวกเขา areshownin
มะเดื่อ 5 และ 6 มะเดื่อ. 5 forall คอมโพสิต andMn2O3 (Mn3þ) มาตรฐานตัวอย่าง suggestinganexistenceofacouplingofMnoxidation statesinallcompositesamples (Mn2þ / Mn3þ) MovingtoFe K-ขอบ theedgeenergyvaluesareconsistentwiththeedgeen- ergy ofFe2O3 (Fe3þ) standardsamplessuggestingthatFeatomsin ทั้งหมดsampleshavetheoxidationstatesof3þ Thesesuchvalence statesareagreedwiththeMnFe2O4 นิล structure.However, เหล่านี้ XANESresultscannotexactlyanswerthestructureof MnFe2O4 structureeithernormalspinelstructure นิล, A2þ [Tet] (B2 3) [ตุลาคม] O4, orinversespinelstructure, B3þ [Tet] (A2þB3þ) [ตุลาคม] O4, especiallylocalstructureofMnatomswhichexhibitamixed oxidationstateof2þและ 3, respectively.Thesecanberevealed ใช้ EXAFSresults .
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