EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
h ps://doi.o g/10.5281/zenodo.17244113 A0707 Page 1/6
A0707
P in ligh syn hesis o Ni ca alys s o CO2RR
Wande son Oli ei a da Sil a* (1), Mu iel Mau on (2), S éphane Aud iaz (2),
Paul G andgeo ge (2), Gioele Bales a (2), Ma hieu Sou enon (1)
(1) Ins i u e o Sys ems Enginee ing, School o Enginee ing, HES-SO Valais-Wallis,
Rue de l’indus ie 23, 1950 Sion/Swi ze land;
(2) Ins i u e iP in , HEIA-FR, HES-SO F ibou g, Rou e de l’Ancienne Pape e ie 180,
1723 Ma ly/Swi ze land;
*Con ac co esponding au ho s: www.EFCF.com/Con ac Reques
Abs ac
The elec o educ ion o CO2 in o aluable chemicals p o ides a sus ainable pa hway o
mi iga e GHG emissions while add essing p essing ene gy and en i onmen al challenges.
This s udy ocuses on a scalable and cos -e ec i e p ocess o ab ica ing ca hodes wi h Ni-
based ca alys s o con e CO2 in o CO by eac i e inkje p in ing. Me al p ecu so -based
inks we e o mula ed o he p ocess and p in ed using a cus om-buil inkje p in e . Pos -
p in ing using a xenon lash lamp was employed o educe he nickel me al p ecu so in o
ac i e ca alys s uc u es. The ull p ocess is called p in ligh syn hesis (Figu e 1). This
me hod educes ene gy consump ion and p oduc ion ime compa ed o con en ional high-
empe a u e syn hesis. SEM/EDX and XRD analysis con i med uni o m ca alys deposi ion
and p edominan p esence o me allic Ni a e he p in ligh syn hesis p ocess. Mic owa e
plasma a omic emission spec ome y (MP-AES) analysis e idenced a con e sion a e o
app oxima ely 80% om nickel p ecu so in o me allic Ni. Elec ochemical cha ac e iza ions,
including cyclic ol amme y and ch onoampe ome y coupled o gas ch oma og aphy
analysis, con i med he e iciency o he syn hesized Ni/C PLS ca alys (0.5 mgNi/cm²) o
selec i e CO2 con e sion in o CO, wi h a a adaic e iciency o 64% a -0.75V ( s RHE).
Figu e 1: Schema ic o he p in ligh syn hesis p ocess.
EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
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In oduc ion
The elec ochemical educ ion o ca bon dioxide (CO₂RR) is a p omising s a egy o
add essing wo o he mos c i ical challenges nowadays: (i) clima e change and (ii) he
sus ainable p oduc ion o uels and chemicals. CO2 ecycling in o aluable p oduc s h ough
elec o educ ion p o ides a pa hway o close he ca bon loop, po en ially achie ing ca bon
neu ali y when coupled wi h enewable elec ici y sou ces. Mo eo e , CO₂RR ope a es
unde ela i ely mild condi ions, is compa ible wi h exis ing chemical in as uc u e, and
suppo s he de elopmen o decen alized p oduc ion sys ems, making i a scalable and
economically a ac i e solu ion o a ci cula ca bon economy. As esea ch p og esses,
ad ancemen s in ca alys design and eac o enginee ing a e equi ed o u he imp o e he
e iciency and selec i i y o CO2 elec o educ ion in o added- alue compounds/ uels.
1. Scien i ic App oach
The elec ochemical educ ion o CO2 can be con olled mainly by he ca alys ype and
applied po en ial, p o iding selec i i y o a desi ed added- alue compound/ uel. The CO2RR
can gene a e se e al p oduc s such as o mic acid (HCOOH), ca bon monoxide (CO),
me hanol (CH3OH), e hanol (C2H5OH), me hane (CH4), e hylene (C2H4) and o he
hyd oca bons and alcohols. [1] P ecious me als such as gold and sil e a e commonly
employed as ca alys s o CO2RR, howe e hei high p ice and sca ci y a e limi ing ac o s
o applica ions in p ac ical de ices. In his scena io, non-noble me als such as i on (Fe),
nickel (Ni), cobal (Co), coppe (Cu), e c., ha e gained signi ican a en ion as cos -e ec i e
and ea h-abundan al e na i es o CO₂RR. [2] In pa icula , nickel (Ni) shows o be e ec i e
o con e ing CO₂ o ca bon monoxide (CO), which is well known as a key p ecu so o
syngas and chemical syn hesis. [3-5] Howe e , despi e hei signi ican ad an ages he e
a e s ill se e al challenges in e ms o imp o ing hei selec i i y, ac i i y, and long- e m
du abili y o CO2RR. The e o e, con inued ad ancemen s in ma e ial design, such as
nanos uc u es, ni ogen-doping, and suppo enginee ing, a e key o imp o e he
pe o mance o he non-noble ca alys s o p ac ical CO2 elec o educ ion applica ions. [6-9]
The con en ional me hods o syn hesize ac i e ca alys s o CO2 a e s ill complex and
challenging since mul iple s eps a e equi ed, o example M-N-C om single-a om ca alys s
(M = non-noble me als), equi es no only a long ime o he comple e syn hesis bu also
addi ional cleaning s eps wi h s ong acids, oxic sol en s, and many s eps o hea ing a high
empe a u es a 700-1000°C ( eac o s, o en, d ye s, e c.), which makes challenging he
scale up o he CO2 elec olyze echnology. In his con ex , a new app oach ecen ly
in oduced using a lash ligh i adia ion om a powe ul xenon lash lamp could be a
p omising al e na i e, since i can d i e he mal p ocesses eaching high empe a u es (up
o 2850 ºC) du ing a e y sho esidence ime (mic o- o milliseconds), [10] which can likely
minimize he ca alys nanopa icle g ow h/agglome a ion and likely maximize he single-
a om ca alys si es as ecen ly illus a ed by ew wo ks. [11-14] These indings e idence he
po en ial o his echnology o ca alys syn hesis ha could be po en ially applied o se e al
applica ions such as ab ica ion o ac i e and selec i e ca hodes o CO2 elec olyze s.
The e o e, his s udy aims o in oduce a new p ocess o ab ica ion o ca hodes o CO2RR,
ideally om non-noble me als, di ec ly om comme cially a ailable gas di usion laye s
(con aining MPL wi h po ous ca bon) using a new app oach called p in ligh syn hesis.
EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
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2. Expe imen s
The employed app oach in ol es o mula ing an inkje ink om nickel ni a e (25mgNi/mL)
om wa e and e hanol-based o mula ion, which was p in ed on o a comme cial gas
di usion laye , a ca bon clo h subs a e coa ed wi h a mic opo ous laye ( hickness 400µm,
ca bon black loading 2.5 mg/cm2, PTFE 20-30w %), using an indus ial p in head (Epson
S3200) o c ea e a me al p ecu so laye o 0.5mgNi/cm2. This laye was hen exposed o
lash ligh i adia ion (unde A gon a mosphe e) om a 16kW xenon lash lamp (Exceli as
NobleLigh , Ge many) o 150 ms wi h a o al ene gy densi y o 400 J/cm2, inducing he
educ ion o he nickel sal in o small me al nickel nanopa icles. This en i e p ocess was
deno ed P in Ligh Syn hesis (PLS) and he syn hesized ca alys as Ni/C PLS. [13] The gas
di usion elec ode con aining Ni nanopa icles we e cha ac e ized by XRD and SEM/EDX.
The Ni loadings be o e and a e he lash ligh i adia ion p ocess we e quan i ied by
Mic owa e plasma a omic emission spec ome y (MP-AES). The ca aly ic pe o mance o
CO2 educ ion eac ion (CO2RR) was e alua ed using s anda d elec ochemical echniques,
in a gas- igh wo-compa men cell sepa a ed by a Na ion 211 memb ane in a 0.5 M KHCO3
elec oly e wi h CO2-sa u a ed in he ca hode side, combined wi h gas ch oma og aphy
analysis o quan i y he p oduc s om CO2RR.
3. Resul s
The syn hesized Ni/C PLS elec ode was ini ially cleaned se e al imes wi h wa e o
dissol e/ emo e possible emaining nickel ni a e sal , a e wa ds MP-AES analysis was
pe o med and e idenced a con e sion a e o app oxima ely 80% in o me allic Ni, he
es ima ed con e sion a e was calcula ed om a iplica e o Ni elec odes wi h and wi hou
pos - ea men by lash ligh i adia ion. Figu e 2 shows SEM/EDX images o he Ni/C PLS
syn hesized by p in ligh syn hesis. The images show a uni o m Ni dispe sion o e he
mic opo ous ca bon laye wi h small Ni nanopa icle sizes wi h almos no la ge
agglome a ions. XRD di ac og ams o he Ni/C PLS and Ba e GDL p esen ed in Figu e 3
show ypical c ys allog aphy di ac ion peaks a 44.6, 51.9, 76.46 a ibu ed o he Ni (111),
(200) and (220) planes, espec i ely, (PDF #04-0850), which is a ibu ed o he me allic
Ni.[15] In addi ion, he absence o XRD peaks om nickel oxide, nickel ni i e, nickel ca bide
and/o uncon e ed nickel ni a e sal , sugges s he majo i y o ma ion o me allic nickel by
using he PLS app oach. The e o e, p in ligh syn hesis is a p omising app oach ha
success ully syn he ized Ni nanopa icles di ec ly on a gas di usion laye (GDL).
Figu e 2: SEM/EDX images o he Ni/C PLS syn hesized by p in ligh syn hesis.
EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
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Figu e 3: X- ay di ac og ams o he Ni/C PLS and Ba e GDL.
The ca aly ic pe o mance o he syn hesized Ni/C PLS was ini ially in es iga ed by cyclic
ol amme y (CV), using a s anda d h ee elec ode elec ochemical cell, in KOH 1 M
elec oly e sa u a ed wi h a gon a a scan a e o 5 mV s−1 as shown in Figu e 4a. The CV
p o ile p esen s ypical Ni edox peaks a 1.2-1.45V ( s RHE), he anodic peak shows he Ni
oxida ion s a e om Ni(II) o Ni(III), whe e b-Ni(OH)2 is oxidized o b-NiOOH and he ca hodic
peak shows he educ ion p ocess, his e idence he o ma ion o ac i e Ni ca alys si es by
using PLS me hod. The ca aly ic pe o mance o Ni/C PLS o CO2 elec o educ ion was
e alua ed by linea sweep ol amme y (LSV). The LSV cu es p esen ed in Figu e 4b
showed highe cu en densi y a mo e posi i e onse po en ial o CO2-sa u a ed elec oly e
compa ed o A gon, which e idences he occu ence o CO2 elec o educ ion. Gas
ch oma og aphy analysis coupled wi h elec ochemical es s a cons an po en ial
elec olysis we e pe o med a di e en po en ials o 30 min o quan i y he p oduc s om
CO2RR.[16] As illus a ed by Figu e 4c he CO2 con e sion in o CO s a s a -0.6V ( s RHE)
and shows a maximum a adaic e iciency o CO a -0.75V ( s RHE) wi h 64% and cu en
densi y o 6mA cm-2 (Figu e 4d), a mo e ca hodic po en ials and cu en densi ies H2
p oduc ion is likely a o ed due o he CO2 mass anspo limi a ions, howe e he FECO
could be u he imp o ed by using a low cell con igu a ion. O e all, Ni/C PLS ca alys
demons a ed a p omising ac i i y and selec i i y o CO2RR o CO, howe e , u he PLS
imp o emen s will con inue o be explo ed in o de o achie e a highe a adaic selec i i y
o CO (>90%) as al eady epo ed by p e ious wo ks,[3,5] ha ypically apply nickel single-
a om ca alys s (Ni SACs) suppo ed on ni ogen-doped ca bon (NC) ma e ials, howe e om
complex and ime consuming syn hesis p o ocols, on he o he hand PLS has he ad an age
o be a as e and simple app oach. The e o e, his inno a i e app oach (p in ligh syn hesis)
can manu ac u e ac i e gas di usion elec odes (po en ially om di e en me als, alloys
and/o SACs) o elec ochemical CO2 educ ion, pa ing he way o mo e sus ainable and
e icien me hods o add ess global ca bon emissions and c ea e alue-added p oduc s.
EFCF 2025: Low-Temp. Fuel Cells, Elec olyse s & H2 P ocessing 1 – 4 July 2025, Luce ne Swi ze land
h ps://doi.o g/10.5281/zenodo.17244113 A0707 Page 5/6
Figu e 4: (a) Cyclic ol amme y o Ni/C PLS in KOH 1M sa u a ed wi h A gon a scan a e
o 5 mV s-1. (b) Linea sweep ol amme y o Ni/C PLS in KHCO3 0.5M sa u a ed wi h
A gon and CO2 a scan a e o 5 mV s-1. (c) Fa adaic e iciency o CO and H2 om CO2RR
ca alyzed by Ni/C PLS a di e en po en ials a e 30 minu es o elec olysis in CO2-
sa u a ed KHCO3 0.5M aqueous solu ion and (d) Fa adaic e iciency o CO om CO2RR
ca alyzed by Ni/C PLS a di e en cu en densi ies a e 30 minu es o elec olysis in CO2-
sa u a ed KHCO3 0.5M aqueous solu ion.
Acknowledgemen s
The au ho s hank he HES-SO Uni e si y o Applied Sciences and A s Wes e n
Swi ze land o suppo ing he p ojec P2-RIPCO2-129765. The au ho s wish o hank P o .
Hube H. Gi aul om EPFL o his suppo .
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Keywo ds: EFCF2025, H2, LowTemp. Fuel Cells & Elec olyse s, CO2 educ ion eac ion
(CO2RR); P in ligh syn hesis (PLS); Value-added uels/compounds.
Rema k: This wo k is licensed unde C ea i e Commons A ibu ion 4.0 In e na ional
