Investigation of the interactions and electromagnetic shielding properties of graphene oxide/ platinum nanoparticle composites prepared under low-dose gamma irradiation

In es iga ion o he in e ac ions
and elec omagne ic shielding
p ope ies o g aphene oxide/
pla inum nanopa icle composi es
p epa ed unde low-dose gamma
i adia ion
DejanKepić1,MilošMilo ić1,DušanS edoje ić1,AndjelaS e ano ić1,2,B ankicaGajić1,
James L. Mead3,BlažNa din4,BlažLikoza 5,Jan i Te žan5, Muhammad Yasi 3,
Wa da Saeed3&S e lanaJo ano ić1
A low-dose gamma i adia ion was used o he one-s ep syn hesis o g aphene oxide/pla inum
nanopa icle composi es. Va ious spec oscopic and mic oscopic me hods we e employed o
s uc u allyandmo phologicallycha ac e ize hep epa edcomposi es,and hena u eo  he
in e ac ions be ween g aphene oxide shee s and pla inum clus e s was in es iga ed using densi y
unc ion heo y (DFT). Gamma i adia ion caused he educ ion o hexachlo opla inic acid, esul ing in
he o ma ion o P nanopa icles and he simul aneous pa ial educ ion o g aphene oxide (GO). P
nanopa iclessyn hesizeda doseso 10and20kGyshowedahomogeneousGOsu aceco e agewi h
ahighpo iono pa icleswi hsizeso up o10nm.TheDFT esul sindica eadi e enceinelec ical
conduc i i ybe weenGOandP NPs.Thiscouldcausecha ge edis ibu ionac oss hecon ac a ea,
c ea ing a conduc i e ne wo k a he in e ace ha should enhance he EMI shielding capabili ies o
hecomposi e.Theshieldinge iciencyo  hecomposi esmeasu eda  heXbandshowedablockage
o 77%o  heinciden elec omagne icwa ea acen e  equencyo 10GHz.Thecomposi ep epa ed
a a20kGydoseexhibi edag ea e con ibu ion omamisma chlosscomponen ,a ibu ed o he
imp o ed elec ical conduc i i y induced by i adia ion.
Keywo ds G aphene oxide, Pla inum nanopa icles, Composi es, Gamma i adia ion, Elec omagne ic
shielding, Densi y unc ional heo y
An inc easing numbe o mode n-day gadge s ha make ou li es easie sa u a e ou en i onmen wi h
elec omagne ic wa es (EMW), causing elec omagne ic wa e pollu ion. The e ec s o EMW exposu e on li ing
o ganisms a e s ill deba able, and i is specula ed ha low- equency elec omagne ic ields migh a ec sleep
quali y, inc ease s ess le els, igge dep ession and anxie y1, o e en inc ease he isk o b ain umo s2. On
he o he hand, he sa u a ion o elec omagne ic wa es leads o elec omagne ic in e e ence (EMI), which
can de ac om he de ice’s pe o mance and sho en i s li e ime. To comba hese issues, i is essen ial o
de elop ma e ials ha can p o ec people and ins umen s om he e ec s o elec omagne ic wa es. Typical
EMI shielding ma e ials include me als in he o m o shee s o oams3, wo-dimensional ansi ion me al
ca bides, ni ides, and ca boni ides known as MXenes4, cemen -based ma e ials5, as well as a ious ca bon-
based ma e ials, such as ca bon nano ubes, g aphene and i s de i a i es, and ca bon ibe s6,7.
1Vinča Ins i u e o Nuclea Sciences - Na ional Ins i u e o he Republic o Se bia, Uni e si y o Belg ade, Mihajla
Pe o ića Alasa 12-14, Belg ade 11351, Se bia. 2Facul y o Chemis y, Uni e si y o Belg ade, S uden ski g 12-
16, Belg ade 11158, Se bia. 3Depa men o Compu ing Science, Uni e si y o Oldenbu g, D-26129 Oldenbu g,
Ge many. 4Facul y o Polyme Technology, Oza e 19, Slo enj G adec 2380, Slo enia. 5Depa men o Ca alysis
and Chemical Reac ion Enginee ing, Na ional Ins i u e o Chemis y, Hajd iho a 19, Ljubljana SI-1000, Slo enia.
email: d.k[email p o ec ed]
OPEN
Scien i icRepo s | 2025 15:26924 1
| h ps://doi.o g/10.1038/s41598-025-12655-7
www.na u e.com/scien i ic epo s
Me als possess excellen elec ical conduc i i y, which makes hem e y e ec i e a e lec ing and abso bing
elec omagne ic wa es. Chen e al. de eloped coppe -coa ed ca bon ibe composi es and epo ed an EMI
shielding e ec i eness o 83.1 dB, which was oughly 30 dB highe han ha o p is ine ca bon ibe ab ics8.
Howe e , me als a e hea y, which limi s hei applica ions in ae ospace, au omo i e, po able elec onics, and
wea able de ices. Ano he d awback is hei suscep ibili y o co osion and igidi y. Unlike me als, MXenes a e
ligh weigh and ha e be e lexibili y. This, combined wi h hei excellen conduc i i y and a la ge su ace a ea,
p o ides high EMI shielding e ec i eness e en a low hickness. The ul a hin, ee-s anding ilms o Ti3C2Tx
MXene/nanoc ys alline cellulose composi e exhibi ed an EMI shielding e ec i eness o 44 dB9. In ano he
wo k, Tan e al. p epa ed a 15μm- hick polyimide/Ti3C2Tx composi e ilm which exhibi ed an ou s anding
EMI shielding e ec i eness o 37 dB in he X-band ange10. Bu he widesp ead applica ion o MXenes in EMI
shielding ma e ials is mainly limi ed by hei cos .
An ideal EMI shielding ma e ial is elas ic, hin, ligh weigh , du able, and s able. G aphene and i s de i a i es
and composi es ul ill hese equi emen s and ha e ecen ly become he subjec o nume ous s udies in shielding
ma e ials11. G aphene oxide (GO) and educed g aphene oxide ( GO) o e some bene i s o e g aphene in e ms
o cos -e ec i eness and p ocessabili y. GO, o example, is he oxidized o m o g aphene wi h a signi ican
po ion o oxygen-con aining unc ional g oups a ached o he g aphene shee s, making GO dispe sible in
wa e . Besides o ming hose unc ional g oups, he oxida ion o g aphene also inc eases he bandgap and
in oduces de ec s in he sp2 domains o he g aphene s uc u e12. The s uc u e migh be pa ially eco e ed
by educing GO and ob aining GO, which has ewe unc ional g oups and highe elec ical conduc i i y
han GO. Simila o p is ine g aphene, bo h GO and GO ha e la ge su ace a eas, which, in combina ion wi h
he p esen unc ional g oups, o e he possibili y o co alen o nonco alen bonding o a ious molecules,
polyme chains, o nanopa icles, hus c ea ing hyb id nanocomposi e ma e ials ha exhibi supe io p ope ies
compa ed o hei componen s13. Addi ionally, a ious g aphene- and ca bon-based ma e ials we e in es iga ed
o EMI shielding applica ions. Milenko ic e al. ob ained composi es o GO and sil e nanowi es (AgNWs) in
di e en GO/AgNW a ios and epo ed EMI shielding e ec i eness om 0.9 dB o 4.5 dB14. Sil e nanopa icles
ancho ed on elec ochemically ex olia ed g aphene showed 32% o he powe ansmi ed h ough he sample
a 2GHz15. In con as , ca bonized biowas e ma e ials we e able o block 78.5% o he inciden elec omagne ic
wa e16.
Recen ly, emendous a en ion has been de o ed o pla inum nanopa icles due o hei ich elec onic
s uc u e, s abili y, ou s anding he mal and elec ical conduc i i y, and non oxici y17. Due o hei ema kable
p ope ies, pla inum nanopa icles (P NPs) a e widely in es iga ed o biomedical applica ions18, ca alysis19,20,
and senso applica ions21,22, among o he s. Thei p ope ies a e con olled by he ab ica ion p ocess.
Con en ional chemical syn hesis implies he educ ion o P NP p ecu so s such as hexachlo opla inic acid
(H2P Cl6) by di e en educing agen s ha in luence he size, shape, yields, and s abili y o he ob ained P NPs17.
Fo example, by educing hexachlo opla inic acid wi h sodium bo ohyd ide, i is possible o ob ain P NPs wi h
sizes o a ound 6nm23. Swi ching he educing agen o o maldehyde o hyd ogen leads o an inc ease in P NP
size24. Mo eo e , hyd azine25, o mic acid26, o asco bic acid27 can also be used o he educ ion. Con en ional
chemical syn hesis also implies he p esence o a s abilizing agen ha p e en s o e g ow h o agglome a ion o
P NPs, such as e hylene glycol (EG) o poly( inyl py olidone) (PVP)23,28.
Radioly ic syn hesis eme ges as an al e na i e o con en ional syn hesis, o e ing bene i s in e ms o ime
and chemical consump ion. Radia ion enables he homogeneous gene a ion o nuclei and he o ma ion o pu e
me allic nanopa icles wi hou esiduals and by-p oduc s29. Wang e al. applied a gamma i adia ion s a egy o
deco a e mul i-walled ca bon nano ubes wi h uni o m P NPs o he elec oca alys s in uel cell applica ions30.
A simila pa hway was ollowed o p epa e P NP/g aphene ae ogel o he ca aly ic educ ion o 4-ni ophenol31,
GO-P NP composi e o ab ica ion o a coun e elec ode in dye-sensi ized sola cells32, GO-P NP composi e
o supe capaci o elec odes33, he polygonal angle P NPs ancho ed o N-doped GO o he oxygen educ ion
eac ion ca alysis34, o GO-P NP nanoca alys o he elec o-oxida ion o me hanol35. Howe e , all he
a o emen ioned p ocedu es in ol e high doses o gamma i adia ion anging om 50 o 300kGy.
He e, we employed low-dose gamma i adia ion (1-20kGy) o he syn hesis o P NPs ancho ed o GO
shee s in a one-s ep p ocedu e. Wi h low i adia ion doses, he s udy aims o p e en he c ea ion o de ec s
due o he knocking ou and spa e ing o C a oms om he g aphene s uc u e36 and o p ese e sp2 egions.
Addi ionally, by applying low i adia ion doses, nanopa icle syn hesis becomes bo h ime- and cos -e ec i e,
he eby con ibu ing o i s sus ainabili y. The s uc u al and mo phological p ope ies o he p epa ed GO-P NP
composi es we e ho oughly examined, and he na u e o he in e ac ions be ween g aphene oxide shee s and
pla inum clus e s was in es iga ed using densi y unc ion heo y (DFT). Addi ionally, we examined he capabili y
o composi es o p e en he ansmission o elec omagne ic wa es wi hin he 8–12GHz equency ange.
Me hods
Syn hesis o GO
A modi ied Humme ’s me hod was used o syn hesize GO, as p e iously epo ed37. In sho , concen a ed
sul u ic acid (23.3 mL, Ca lo E ba Reagen s) was mixed wi h g aphi e powde (1g, KS6, TIMREX®) in an ice
ba h unde s i ing. Then, KMnO4 (3g, Me ck) was slowly added o he mix u e, and he s i ing was con inued
o 15min. Nex , 50 mL o wa e was added and he empe a u e o he eac ion mix u e was kep a 40°C o
30min and hen a 90°C o 15min. A e ha ime, he eac ion mix u e was pou ed in o 170 mL o wa e
which con ained 5 mL o hyd ogen pe oxide (30 ol%, Ca l Ro h). GO lakes we e p ecipi a ed by cen i uga ion
and washed se e al imes wi h MiliQ wa e un il he pH o he supe na an was 7. The GO powde was d ied in
a acuum o en a 80°C.
Scien i icRepo s | 2025 15:26924 2
| h ps://doi.o g/10.1038/s41598-025-12655-7
www.na u e.com/scien i ic epo s/
Syn hesiso GO-P NPcomposi es
A s able GO wa e dispe sion wi h a GO concen a ion o 1mg mL-1 was p epa ed using an ul asound ba h.
The dispe sion (200 mL) was mixed wi h isop opyl alcohol (20 mL, Fishe Chemicals) and hexachlo opla inic
acid hexahyd a e (11.4mg, Tokyo Chemical Indus y Co.) unde s i ing. The mix u e was hen di ided equally
in o h ee ials and a gon was pu ged h ough each ial o 15min, a e which he ials we e he me ically
sealed. The ials we e exposed o gamma- ay lux om he 60Co nuclide o ecei e 1, 10, and 20kGy doses,
espec i ely. A e he i adia ion, he samples we e il e ed o emo e eac ion byp oduc s h ough 0.45μm
po e size cellulose ni a e memb anes (Wha man) and washed wi h MiliQ wa e . Fo he syn hesis o P NP in
he absence o GO, hexachlo opla inic acid hexahyd a e was dissol ed in a wa e /isop opyl alcohol mix u e o
achie e a concen a ion o 1 × 10-4 M, and he mix u e was spli in o wo ials. A e pu ging a gon, he ials we e
i adia ed a doses o 1 and 20kGy, espec i ely.
Cha ac e iza ion
The UV-Vis abso p ion spec a we e eco ded on he LLG-uniSPEC 2 spec opho ome e in he ange o 200–
800nm. Fo he measu emen s, a small quan i y o he d ied ma e ial was dispe sed in wa e , and spec a we e
eco ded in qua z cu e es a oom empe a u e. The X- ay di ac ion (XRD) measu emen s we e pe o med on
a Philips PW 1050 X- ay powde di ac ome e using Ni- il e ed Cu Kα adia ion and B agg-B en ano ocusing
geome y. The di ac ion in ensi y was eco ded in he 2θ ange o 10-90° wi h a s ep size o 0.02° and a coun ing
ime o 5s pe s ep. E a so wa e was used o he de e mina ion o phase composi ion. The uni cell pa ame e s
o he pla inum phase we e ex ac ed om XRD pa e ns by using Powde Cell so wa e. The c ys alli e size (Xs)
o p ecipi a ed P has been es ima ed om he hal -wid h β½ o he (111) P peak, by using Sche e ’s Eq.
Xs =0
.
9×
λ/
(
β1
/
2×cos
θ
)
(1)
and o he calcula ion o he in e laye dis ance d00l be ween shee s o g aphene oxide (GO) and educed
g aphene oxide ( GO), B agg’s law has been used,
d00l=λ/ (2 ×sin θ)
(2)
whe e λ is he wa eleng h o inciden X- ays (1.542 Å) and θ is he B agg angle. A ansmission elec on
mic oscope (TEM) examina ion o he samples was ca ied ou using a JEOL (Tokyo, Japan) JEM-2100F wi h
an accele a ion ol age o 200kV. The composi e samples we e dispe sed in e hanol using an ul asound ba h
and a d op o he mix u e was placed on lacey ca bon coppe g ids (200 mesh, Aga Scien i ic) and d ied in
he ai . Fo P NP samples p epa ed wi hou GO, a ew d ops o wa e dispe sion we e placed on holey ca bon
coppe g ids (200 mesh, Aga Scien i ic) and d ied in he ai . The pa icle size dis ibu ions we e calcula ed
using Digi alMic og aph so wa e (Ga an, Inc.). The mic os uc u e and elemen al mapping o he composi es
we e in es iga ed using a Field Emission Gun Scanning Elec on Mic oscope (FESEM, Mi a3 Tescan, Ox o d,
UK) a 20kV elec on ene gy in a high acuum. EDS analysis was conduc ed using an INCAx-ac LN2- ee
Analy ical Silicon D i De ec o (Ox o d Ins umen s, Ox o d, UK), wi h he Pen aFET® P ecision and AZ ec
so wa e e sion 4.3. X- ay pho oelec on spec oscopy (XPS) was used o analyse he chemical s a es o P and
C. The measu emen s we e pe o med wi h a PHI Ve saP obe 3 AD (Phi, Chanhassen, US) equipped wi h a
monoch oma ic Al Kα X- ay sou ce. The esolu ion o he analyze was 0.65eV. A dual-beam neu alisa ion
sys em (elec ons and ions) was used o a enua e he cha ging o he sample. The esul ing peak shi due o
cha ge neu alisa ion was co ec ed by aligning he me allic P -4 peak o 71eV. Su ey spec a we e eco ded
a a pass ene gy o 224eV wi h a s ep size o 0.8eV, while high- esolu ion spec a we e eco ded a a pass
ene gy o 27eV wi h a s ep size o 0.05eV. Th ee sweeps we e pe o med o he su ey spec a and 30 sweeps
o he high- esolu ion spec a. Spec al decon olu ion was pe o med wi h he Mul ipak so wa e. Fo he
elec omagne ic shielding e iciency measu emen s, d y samples we e mixed wi h a sodium silica e esin o
p oduce a homogeneous pas e. The p epa ed GO-P NP pas e concen a ions we e 0.33g mL-1. The pas es we e
deposi ed on a 0.2mm- hick Plexiglass shee co e ed wi h a pape mold and o med in o 22.86mm × 10.16mm
hin ilms so ha he size co esponds o he inne dimensions o WR-90 wa eguide adap e s used o he
measu emen s. The ansmission coe icien s in he X-band (8–12GHz equency ange) we e measu ed using a
Rohde & Schwa z ZVA 24 Vec o Ne wo k Analyze (VNA, Munich, Ge many).
Compu a ional de ails
All calcula ions we e pe o med using he Gaussian 09 sui e o p og ams. We used densi y unc ional heo y
(DFT) o examine he s uc u al pa ame e s, elec onic s uc u es, and in e ac ion ene gies o P /GO composi es.
The P 55, P 18, and P 21 clus e s we e employed o model he elec onic s uc u es o P nanopa icles and hei
{111} and {100} ace s, espec i ely. To model g aphene oxide (GO), we u ilized he C40H16O2(OH)2 clus e ,
which possesses wo epoxy and wo hyd oxyl basal g oups. Using he B3LYP-D3 unc ion38,39, in conjunc ion
wi h he 6-31G(d, p) basis se o ligh a oms40 and he LANL2DZ basis se wi h pseudo po en ials o P a oms,
he g ound-s a e geome ies o he P 18/C40H16O2(OH)2 and P 21/C40H16O2(OH)2 adduc s a e op imized.
The pla inum a oms o he P 18 and P 21 clus e s we e ozen du ing he op imiza ion p ocess o p ese e he
c ys al s uc u es ha ep esen (111) and (100) planes, while all a oms o he C40H16O2(OH)2 clus e we e
elaxed. The non-co alen in e ac ions wi hin he P 18/C40H16O2(OH)2 and P 21/C40H16O2(OH)2 sys ems a e
depic ed h ough he in e ac ion ene gies (Ein ), and coun e poise co ec ions a e used o emo e he basis se
supe posi ion e o (BSSE). This compu a ion echnique makes use o he ollowing equa ions:
∆Ein =EP 18/21 +EGO −Eadduc
(3)
Scien i icRepo s | 2025 15:26924 3
| h ps://doi.o g/10.1038/s41598-025-12655-7
www.na u e.com/scien i ic epo s/
∆Ein CP =Ein +EBSSE
(4)
The Mulliken cha ges and molecula elec os a ic po en ials (MEPs) a e compu ed o illus a e he cha ge
dis ibu ions on hese composi es. All hese calcula ions a e pe o med in he gas phase. GaussView so wa e
was used o ob ain he molecula ep esen a ion o he clus e s, ESP maps, Mulliken colo schemes, and FMO
o bi als, whe eas he GaussSum p og am was u ilized o acqui ing o al and pa ial densi y o s a e (TDOS/
PDOS) diag ams.
Resul sanddiscussion
Pla inum nanopa icles (P NPs) we e syn hesized di ec ly on g aphene oxide (GO) shee s in a one-s ep p ocess
using low-dose gamma i adia ion o he mix u e o hexachlo opla inic acid and GO in wa e . Du ing i adia ion,
he adiolysis o wa e gene a es ee adicals, ions, and neu al molecules, wi h hyd a ed elec ons (e⁻(aq)) and
hyd oxyl adicals (OH•) being he mos abundan species41. The addi ion o isop opyl alcohol ac s as a sca enge
o oxida i e species, such as hyd oxyl adicals and hyd ogen pe oxide, which p omo es he p edominance o he
educ ion eac ion. The educing species o med du ing adiolysis, p ima ily hyd a ed elec ons and hyd ogen
adicals (H•), educe P Cl62- ions o me allic pla inum (P 0), esul ing in he nuclea ion and g ow h o P NPs29.
Simul aneously, he i adia ion pa ially educes he GO, as indica ed by a change in he colo o he dispe sions.
While he sample i adia ed a 1kGy emained yellow-b own, he dispe sions u ned da ke a doses o 10
and 20kGy. I was epo ed ha hyd a ed elec ons show a high a ini y owa ds ca bonyl and ca boxyl g oups
p esen in GO, which ac as apping cen e s o hese elec ons42. Hence, hyd a ed elec ons can emo e
oxygen-con aining g oups om he GO su ace, esul ing in i s educ ion. Since he numbe o hese elec ons
depends on he abso bed adia ion dose, i is possible o con ol he deg ee o GO deoxygena ion by selec ing
he app op ia e dose43.
A e i adia ion, he UV-Vis spec a o he GO-P NPs dispe sed in wa e we e eco ded (Fig. 1). GO exhibi s
one b oad, in ensi e peak a ~230nm, esul ing om he π-π* ansi ion o a oma ic C-C bonds, and one smalle
ea u e a ~300nm, o igina ing om he n-π* ansi ion o C-O bonds44. The educ ion o GO unde gamma
i adia ion, indica ed by he change o colo o he dispe sions, ini ia es he g adual edshi o he 230nm peak
and he simul aneous disappea ance o he 300nm ea u e45. On he o he hand, P NPs ha e a su ace plasmon
esonance (SPR) peak ha appea s in he UV egion46,47. As shown in Fig. 1, wi h an inc ease in he i adia ion
dose, he p e ailing maximum shi s in posi ion om 241nm o he lowes o 268nm o he highes applied
dose. This shi occu s as a join con ibu ion o he edshi o he a oma ic C-C bonds peak o GO and he
occu ence o he SPR peak o P NPs. To p o e he con ibu ion o P NPs, we p epa ed P NPs wi hou GO a he
doses o 1 and 20kGy and eco ded UV-Vis spec a (inse o Fig. 1). Bo h spec a show a b oad peak cen e ed
a 266nm, which is mo e p ominen o he P NPs p epa ed a 20kGy.
To inspec he mo phology o he composi es, we pe o med FESEM analysis (Fig. S1, Suppo ing
In o ma ion). GO is p esen as s acked shee s wi h c umbled edges, which is an inhe en cha ac e is ic o he
d ied GO sample. I adia ed samples show GO shee s co e ed wi h P NPs. EDS elemen al maps show he
dis ibu ion o he cons i uen elemen s o he composi es (Fig. 2). GO shee s a e uni o mly oxidized and,
besides C and O, show ace amoun s o S as a esidual om he syn hesis. GO-P NP composi es p epa ed a 10
and 20kGy show homogeneous co e age o GO shee s wi h P NPs. On he o he hand, he GO-P NP sample
Fig. 1. No malized UV-Vis spec a o GO and GO-P NP composi es and P NPs syn hesized wi hou GO
(inse ).
Scien i icRepo s | 2025 15:26924 4
| h ps://doi.o g/10.1038/s41598-025-12655-7
www.na u e.com/scien i ic epo s/
p epa ed a he lowes applied dose (1kGy) exhibi s islands wi h spa se popula ions o P NPs and a eas whe e
P NPs appea la ge and clus e ed. The weigh and a omic pe cen ages o he cons i uen elemen s o he GO
and GO-P NP composi es a e gi en in Table S1 (Suppo ing In o ma ion). The O/C a io dec eases wi h an
inc ease in he i adia ion dose, indica ing a educ ion in GO unde gamma i adia ion. The composi e GO-
P NP p epa ed a 10kGy showed he highes pe cen age o P .
Figu e 3 ep esen s he TEM images o GO-P NP composi es p epa ed a di e en i adia ion doses. The
images e eal he w inkles and ipples o he GO shee s, wi h spo adic occu ences o olded edges. The di e ence
in he a omic numbe be ween P and C enables a clea dis inc ion o he o med P NPs a he GO su ace. P NPs
a e mos ly sphe ical, wi h a small po ion o i egula ly shaped pa icles. A de ailed inspec ion o TEM images o
he composi e p epa ed a 1kGy e eals he p esence o agglome a es o P NPs, which ollows he EDS analysis.
On he o he hand, P NPs syn hesized a doses o 10 and 20kGy appea o be homogeneously dis ibu ed o e
he GO shee s. The samples p epa ed a he lowes and he highe doses also di e in P NP size dis ibu ion
(Fig. 3d). While he majo i y o P NPs syn hesized a 1kGy a e bigge han 10nm, nanopa icles syn hesized
a he highe doses a e smalle and mos o hem ha e a size o less han 10nm. The educ ion in nanopa icles’
size wi h an inc ease in he i adia ion dose has been epo ed p e iously48–50. The size dependence on he
i adia ion dose is guided by he wo successi e p ocesses: nuclea ion and agg ega ion29. A lowe i adia ion
doses, he numbe o nuclei gene a ed is lowe han he amoun o a ailable me al ions o g ow h, esul ing in
he o ma ion o la ge pa icles. Con e sely, a highe doses, mos o he p ecu so is used o p oduce a g ea e
numbe o nuclei, exceeding he concen a ion o emaining un educed ions, which in u n limi s g ow h and
yields smalle pa icles.
To illus a e he in luence o GO on he o ma ion o P NPs, we ollowed he same expe imen al p ocedu e in
he absence o GO o o he s abilizing agen s, and he samples we e i adia ed a 1 and 20kGy doses. Fo bo h
Fig. 2. SEM image and he co esponding EDS elemen al maps o C, O, and P o (a) GO, (b) GO-P NPs
p epa ed a 1kGy, (c) GO-P NPs p epa ed a 10kGy, and (d) GO-P NPs p epa ed a 20kGy.
Scien i icRepo s | 2025 15:26924 5
| h ps://doi.o g/10.1038/s41598-025-12655-7
www.na u e.com/scien i ic epo s/

he applied doses, P NP agglome a es la ge han 100nm o unde ined shape we e no iced (Fig. S2, Suppo ing
In o ma ion). Besides, he colloids o as-p epa ed P NPs we e uns able and ended o p ecipi a e.
Gamma i adia ion c ea es a educ i e en i onmen ha causes he p ecipi a ion o elemen al P and he
pa ial educ ion o GO o GO, as e idenced by XRD in Fig. 4. P c ys allized wi hin cubic Fm-3m s.g. no
225 (PDF no. 04-802) wi h he la ice pa ame e a ≈ 3.93 Å o all i adia ed samples (Table S2, Suppo ing
In o ma ion). The ob ained P phase is nanoc ys alline, as indica ed by i s b oad XRD e lec ions, wi h an
es ima ed c ys alli e size o a ound 20nm o he P NPs p epa ed a 1kGy and a ound 14nm o hose p epa ed
a 10 and 20kGy. Mo eo e , by compa ing es ima ed c ys alli e sizes wi h he pa icle sizes isible in Fig. 3
(TEM), one can deduce ha obse ed P nanopa icles a e monoc ys als. In he XRD p o ile o he s a ing
GO, he posi ion o he (001) e lec ion a 2θ ≈ 11.6° co esponds o he in e plana dis ance o a ound 7.63 Å
be ween basal planes o GO51. A e gamma i adia ion, he (001) peak disappea s om he XRD pa e ns wi h
he eme gence o he new peak (002) a 2θ ≈ 23.4°, which co esponds o he in e plana dis ance o a ound
3.80 Å be ween he basal planes o pa ially educed GO52. This in e laye sh inkage occu s due o he loss o
g aphene oxide’s unc ional g oups a e gamma i adia ion, con i ming i s subsequen educ ion11.
To in es iga e he elemen al composi ion, chemical s a e, and elec onic en i onmen , he composi es we e
deposi ed on Al subs a es and XPS analysis was pe o med (Fig. 5). As can be seen, he peaks o he P
egion align well wi h he li e a u e da a53. A a 1kGy i adia ion dose, app oxima ely 20% o he pla inum
oxide is p esen , wi h he p ima y peak posi ioned a 74.3eV. This is app oxima ely 0.2eV lowe han he alue
epo ed in he li e a u e54. This is expec ed due o he smalle pa icles being close o elec onega i e species,
such as oxides55. The absence o XRD e lec ions o pla inum oxide, as de ec ed by XPS, indica es i s amo phous
na u e. The ca bon egion shows a majo i y o sp2 hyb idized ca bon-ca bon bonds, posi ioned a app oxima ely
284 eV56. As expec ed, a he dose o 1kGy, he e is sligh ly mo e oxidized ca bon p esen (~5%), wi h peaks
posi ioned a app oxima ely 286 and 288eV, compa ed o he composi e p epa ed a he highe dose. This
co ela es wi h he UV-Vis and EDS da a.
Fig. 3. TEM images o (a) GO-P NPs p epa ed a 1kGy, (b) GO-P NPs p epa ed a 10kGy, (c) GO-P NPs
p epa ed a 20kGy, and (d) pa icle size dis ibu ion o P NPs syn hesized a di e en i adia ion doses.
Scien i icRepo s | 2025 15:26924 6
| h ps://doi.o g/10.1038/s41598-025-12655-7
www.na u e.com/scien i ic epo s/
Compu a ional analysis
The P 55 clus e has been chosen as a benchma k o calcula ing elec onic s uc u es and in e ac ion ene gies
be ween GO and P NPs. This clus e eplica es a ace-cen e ed cubic la ice ( cc) o bulk pla inum wi h a body-
cen e ed cuboc ahed al pa e n (Oh). This makes i possible o use he comple e Oh symme y, which simpli ies
he compu a ional p ocedu e using a ully sel -consis en DFT app oach, wi h app op ia e basis se s and
compu a ionally p ecise nume ical in eg a ion.
The op imized s uc u e o he P 55 clus e is shown in Fig. S3a (Suppo ing In o ma ion), wi h wo indica ed
c ys alog aphic planes. The P 55 clus e consis s o i e {100} laye s s acked along he C4-axis, which include
9, 12, 13, 12, and 9 pla inum a oms, wi h a P -P dis ance o 2.79 Å and an in e plane dis ance o 1.97 Å. On
he o he hand, his clus e can also be iewed as s acked {111} su aces, consis ing o i e consecu i e {111}
nano- lakes o 6, 12, 19, 12, and 6 pla inum a oms wi h an in e plane dis ance o 2.28 Å and o e all adius o
1.1nm. Fig. S3b combines di e en colo s o show elec os a ic po en ial maps (MEP) o he P 55 clus e . G een
indica es egions wi h ze o po en ial, whe eas ed and blue display he molecules’ elec on- ich (nega i e) and
elec on-de icien (posi i e) pa s. The MEP e eals ha he egion a ound he clus e ’s edges is elec oposi i e
(blue), while nega i e egions ( ed) a e hose placed a he ace s. I should be s essed ha {100} su aces a e
Fig. 5. The P (le ) and C ( igh ) spec a om XPS analysis o GO-P NP composi es p epa ed a adia ion
doses o 1kGy and 10kGy. The alumina peak o igina es om he subs a e.
Fig. 4. XRD spec a o GO and GO-P NP composi es wi h e lec ions o P e e ence ca d PDF # 04-802. GO
peaks a e indexed wi h black and P peaks wi h ed indices.
Scien i icRepo s | 2025 15:26924 7
| h ps://doi.o g/10.1038/s41598-025-12655-7
www.na u e.com/scien i ic epo s/
mo e nega i ely cha ged han {111}. Acco ding o he calcula ed Mulliken cha ges, he pla inum a oms a he
ex e io o he clus e a e almos neu al, while hose in he in e io a e posi i ely cha ged (g een a oms; Fig.
S3b). On he o he hand, he pla inum a om a he clus e ’s cen e is highly nega i ely cha ged ( ed a om). The
calcula ed densi y o s a e (DOS) diag am o he P 55 clus e shows i s elec onic s uc u e, which p o es he
me allic cha ac e o P NPs (Fig. S3c). A smoo h conduc i i y o P NPs may be sugges ed by he elec onic s a es
close o he Fe mi le el, wi h no gap be ween he alence and conduc ion bands.
To educe he compu a ional bu den o calcula ing he in e ac ions wi h GO, we used P 18 and P 21 clus e s
o model {111} and {100} su aces o bulk pla inum, espec i ely. The DOS diag ams o hese clus e s (Figs.
S4a and S6a) a e e y simila o he la ge P 55 clus e , p o ing ha he elec onic s uc u es a e p ese ed. The
P 18 clus e comp ises wo s acked {111} lakes o 6 and 12 a oms, while P 21 consis s o wo o e lapped {100}
planes wi h 9 and 12 P a oms. We used he C40H16O2(OH)2 clus e o mimic he GO su ace ich in hyd oxyl
and epoxy g oups. The co esponding densi y o s a es (DOS) diag am e eals a bandgap o 1.73eV (Fig. S4b),
close o he alue o educed GO. I could be u he no iced ha he e a e no gaps be ween he alence and
conduc ion bands o he P 18@C40H16O2(OH)2 and P 21@C40H16O2(OH)2 adduc s, acco ding o he PDOS/
TDOS diag ams in Figs. S4c, S6c. This may poin o he inc eased conduc i i y o g aphene oxide coa ed wi h
pla inum nanopa icles.
The compu ed Mulliken cha ges (QMulliken) o P 18@C40H16O2(OH)2 and P 21@C40H16O2(OH)2 complexes
a e p esen ed in Figs. S5a, S7a, espec i ely. The esul s indica e cha ge ans e s om GO o he P 18 and P 21
clus e s. Acco ding o he QMulliken, P 18 and P 21 clus e s accep elec on densi ies o 0.44 and 0.31 e-, espec i ely.
This is easonable since he {111} su ace is less nega i ely cha ged han he {100} su ace and may allow o mo e
nega i e cha ges. The elec on-accep ing na u e o he P18 and P 21 clus e s wi hin he P 18/P 21/GO sys ems is
also sugges ed by he molecula elec os a ic maps (MEPs) o he espec i e adduc s (Figs. S5b and S4b). In
bo h sys ems, he GO co e is elec oposi i e (blue), while he P clus e s a e nega i ely cha ged wi h he mos
nega i e egion ( ed) on he con ac su ace a ea. I has been shown ha he in e acial pola iza ion, which
o igina es om he di e ence in elec ical conduc i i y o he ma e ials in he in e ace, con ibu es o he loss
o elec omagne ic wa es.
To de e mine he s eng h o binding be ween GO and P NPs, we used P 18/P 21@C40H16O2(OH)2 adduc s
and e-op imized hem by eezing he s uc u es o P clus e s. The op imized geome ies o hese sys ems a e
p esen ed in Fig. 6. S ong in e ac ions a e indica ed by he sho con ac s (<2.5 Å) be ween P a oms and oxygen
a oms om epoxy and hyd oxyl g oups. The in e ac ion ene gies ha quan i y in e acial bonding be ween
P 18/21 and GO clus e s a e compu ed wi h se e al unc ionals, including G imme’s dispe sion co ec ions (GD2
& GD3). The basis se supe posi ion e o (BSSE) was emo ed by using coun e poise co ec ion. All hese
alues a e summa ized in Table1. The esul s ob ained wi h di e en unc ionals sugges ha he GO clus e
in e ac s s onge wi h {111} han wi h {100} su ace. This is because he {100} plane is mo e nega i ely cha ged
han {111}, causing somewha s onge elec os a ic epulsions wi h nega i ely cha ged oxygen a oms a he
GO su ace. In addi ion, he in e ac ion ene gies ob ained wi h dispe sion-co ec ed unc ionals (GD2) a e
o e es ima ed compa ed o he mo e accu a e GD3 co ec ions o accoun ing dispe sion ene gies (Table1).
Ne e heless, he binding ene gies o -57.5 and -44.5kcal mol-1, calcula ed o {111} and {100} planes a he
B3LYP-D3 le el, sugges signi ican nonco alen binding be ween GO and pla inum nanopa icles.
The p ima y cause o in e acial pola iza ion is he elec ical conduc i i y di e ence be ween GO and P NPs
a he in e ace, which allows cha ge edis ibu ion ac oss he con ac a ea. This is e iden om he densi y o
s a es (DOS) nea he Fe mi le el (Figu es S4 and S6) o P 18/21 and GO, indica ing he di e ing conduc i i y
o he wo ma e ials. As a esul , a conduc i e ne wo k is c ea ed a he in e ace, imp o ing he EMI shielding
capabili ies o his composi e.
EMI shielding measu emen
The sca e ing pa ame e s o he GO-P NP composi e ilms deposi ed on a Plexiglas shee we e measu ed in
he X-band equency. The EMI shielding pe o mance o he composi es was e alua ed using he wa eguide
me hod by placing he sample be ween he wo WR-90 wa eguide adap e s and hen measu ing he S-pa ame e s.
Fig. 6. The op imized s uc u es o (a) P 18@C40H16O2(OH)2 and (b) P 21@C40H16O2(OH)2 adduc s wi h
indica ed nonco alen con ac s.
Scien i icRepo s | 2025 15:26924 8
| h ps://doi.o g/10.1038/s41598-025-12655-7
www.na u e.com/scien i ic epo s/
Acco ding o he wo k by McDowell57, he misma ch loss is de ined a a e e ence plane be ween a sou ce and a
load as he a io o he powe ha would be deli e ed o a conjuga e-ma ched load o he powe deli e ed o he
ac ual load. This pa ame e was calcula ed om he S11 pa ame e using he ollowing equa ion:
L
M
=−10log10 (1−|
S11
|2)
(5)
Simila ly, he e iciency o a ansmission line segmen is de ined as he a io o he powe deli e ed o he load
o he ne inpu powe . Acco dingly, he dissipa ion loss o he shield is de ined as he ecip ocal o his e iciency.
Conside ing he e lec ion coe icien (S11) and he ansmission coe icien (S21), he dissipa ion loss can be
exp essed as:
L
D
=−10log10 (|
S21
|2
/
(1−|
S11
|2))
(6)
The shielding e ec i eness (SE) o he ma e ial was exp essed as he sum o he dissipa ion loss and misma ch
loss:
SE =LD+LM
(7)
The calcula ed dissipa ion loss, misma ch loss, and shielding e ec i eness o GO-P NP composi es p epa ed a
doses o 1 and 20kGy a e plo ed in Fig. 7.
P e ious epo s ha e shown ha p is ine g aphene-based ma e ials show ela i ely poo shielding
pe o mance in he co esponding equency ange15. The educed GO showed a negligible shielding e ec
h oughou he 8–12 GHz ange. In con as , he educed elec ochemically ex olia ed g aphene allowed
ansmission o 91.4% o he inciden wa e and simul aneously had only 8.6% o he e lec ion. Compa ed o
p is ine GO, GO-P NP composi es showed imp o ed SE. An a e age EMI SE in he whole ange o he sample
p epa ed a 1kGy was 9.89±0.77 dB (67.79±2.72%), while o he one a 20kGy i was 10.28±0.81 dB (69.13±
2.76%). A a cen e equency o 10GHz, bo h samples eached he SE alues o 11 dB, which co esponds o a
blockage o 77% o he inciden elec omagne ic wa es. F om Fig. 7, i is e iden ha he shielding o e ed by he
dissipa i e componen s is highe han ha due o he misma ch losses o he sample. Howe e , he o al shielding
e ec i eness emains almos he same o bo h samples. This implies ha bo h samples a e dissipa i e in na u e.
Al hough bo h composi es had simila SE alues, he GO-P NP sample p epa ed a 20kGy showed an inc eased
Fig. 7. LD, LM, and SE alues o (a) GO-P NPs p epa ed a 1kGy and (b) GO-P NPs p epa ed a 20kGy.
(111)−P 18@
C40H16O2(OH)2
(100)−P 21@
C40H16O2(OH)2
ΔE BSSE ΔECP ΔE BSSE ΔECP
ωB97xD (D2) −88.5 19.0 −69.5 −76.9 23.5 −53.4
B3LYP-D2 −110.8 23.5 −87.3 −102.9 28.1 −74.8
PBE0-D3 −69.7 20.2 −49.5 −68.7 25.2 −43.5
B3LYP-D3 −80.2 22.7 −57.5 −72.5 28.0 −44.5
Table 1. The calcula ed binding ene gy (ΔE and ΔECP, kcal mol-1) be ween P 18 (111) and P 21 (100) clus e s
wi h C40H16O2(OH)2, wi h and wi hou co ec ion o BSSE.
Scien i icRepo s | 2025 15:26924 9
| h ps://doi.o g/10.1038/s41598-025-12655-7
www.na u e.com/scien i ic epo s/