Synthesis of Flowerlike Ce1-xZrxO2 as Catalyst Support for Hydrogen
Production from Biogas
Tu Hoan Phuc
Department of Hydrogen Energy Systems, Graduate School of Engineering, Kyushu University, Japan

Subtitle: Ni-loaded ceria microspheres for biogas reforming
INTRODUCTION
Our concept ofdirect-internal reforming (DIR)-SOFC

PSC structure
Ni
CeO2

Electricity

Air

CathodeCH4 CO2(2)H2, CO

Ni

Ni

Electrolyte

Improve the catalytic performance

H2/CO(3)(4)

H2 ; COCO2

Ni/CeO2

CeO2

CeO2-d (4)Anti-sintering
Inorganic fiber

CeO2

Ni

Anti-carbon deposition

Paper-structuredCatalyst (PSC)

Oxygen storage capacity(OSC) of Ceria

CCOAnodeBiogas(CH4+CO2)(1)

H2O/CO2(1) CH4 + CO2 → 2H2 + 2CO(2) CH4 → 2H2 + C(3) CeO2 + dC → CeO2-d + dCO

Ni
Ni

Ni

CeO2-d + d/2 O2(4) CeO2-d + dCO2 → CeO2 + dCO

EXPERIMENTAL
Preparation of flowerlike-CeO2 powder (Ce(F))

Preparation of paper-structured catalysts (PSCs)

Ingredients in the Precursor Solution for Hydrothermal Synthesis
Aiming at Producing Flowerlike-CeO2 Powder (Ce(F)).
Sample Glucose (mol) Acrylic acid (mol) 25 wt% NH4OH (mL)
a0.0150
0.02254.4
b0.0150
0.02255.5
c0.0150
0.02256.6
d0.0150
0.02257.7
e0.00750.02256.6
f0.01500.01506.6
g
0.01500.0300
6.6

Paper-making
process
Water

HOOH

Anionic polymer(Polyacrylamide)

Ceramic fiber: Cf(SiO2: 52 wt%, Al2O3: 48 wt%)

OHO

Paper-making
processOH

1.5 mmRaw ceramic
paper

Impregnation
methodNi-PSC(Basic)

Ce3+5μm

Paper-making process
Co-precipitation (Ni/CeO2/ZrO2 = 50/25/25)

20 mm

Ni/Ce-PSC(Synthesis)

Reduction
treatment
under H2 for
2h at 750CCalcination

NH4OH

Heat-treatment
at 600 oC

Conventional PSC+ H2O

Self-assembly

Drying at
105 oC

Filtration to form
wet-state sheet

Paper-making process
Co-precipitation (Ni/CeO2 = 50/50)

OH

Press at
350 kPa

Pulp fiber

PSC

Formation of flowerlike ceria Ce(F)CH2OHO

Cationic polymer(PDADMAC)

Dry reforming (DRM) tests with PSCs

PSC parameters

Ni/CeZ-PSC(Synthesis)

Reformate composition was analyzed every 0.5 h using
gas chromatography (GC-20B; Shimadzu, Japan).

Colloid precipitation
Interconnected Ce(OH)CO3 petalCe(OH)CO3 – N – R hybrid

Ni/Ce(F)-PSC(Geometry)

Paper-making
process

Test conditions
Temperature: 750 oC
 Fuel composition: CH4:CO2 :N2 = 1:1:1
 Total flow rate: 60 mL min-1
 Gas hourly space velocity (GHSV): ~2500 h-1

Methane conversion (%)

Ni/Ce(F)= [CH4 convert]/ [CH4 in] *100%

RESULTS AND DISCUSSIONCe(F)g after Ni loading

Morphologies of Ce(F)c2 µm

2 µm

d5 µm

20 µm

5 µmfe●●●5 µm♦ Petal thickness was 30 – 50 nm.
3 µm●□Ni NPs♦ Mesoporous CeO2 microsphereswith f 4 - 5 µm were obtained.

g● Cubic CeO2
□ Cubic Ni●♦ Morphology could be controlled
by adjusting the ingredients.

203040●●●607080□50

2 theta (degree)

Ceramic fiber♦ Ni-loaded Ce(F) (Ni/Ce(F)g) was formed.

Ce(F)petals♦ Morphology was remained even after
catalyst loading.
500 nm♦ Ce(F)g with the highest surface area: of 78.8 m2 g-1 was the best.

♦ Ni/Ce(F)g had the specific surface areaof 58.5 m2 g-1.

Structure of prepared PSCs
XRD patterns after reduction

CH4 conversion

CH4 conversion (%)

100♦

Ni/CeZ-PSC

90

Ni/Ce(F)g-PSC

80

Ni/CeZ-PSC
Ni/Ce-PSC

70

Ni-PSC

60
50
4030

Temp: 750 °C
Fuel: CH4:CO2:N2 = 1:1:1
GHSV= 2500 h-1

10SUMMARYTPO profiles after 15 h DRM test

Equilibrium

20*estimated with Scherrer equation from XRD patterns♦ Ni/Ce(F)g was formed into a catalyst-sheet
for the application to DIR-SOFC.

Dry reforming test

Dispersions of catalysts in the fiber network

SBET, Ni loading and Ni Crystallite Size (DNi)
Ni loading
2-1
SBET (m g )DNi* (nm)(wt%)
Ni-PSC
5.8
1258
Ni/Ce(F)g-PSC
32
3
16.8
Ni/Ce-PSC
10.1
4.3
9.1
Ni/CeZ-PSC
24
6.1
1310 µm

12

3

45

6

78

Ni/Ce-PSC
Ni/Ce(F)g-PSC

Ni-PSC00

Mass signal of CO2 (counts)

bIntensity (a.u.)

aNi/Ce(F)g in fiber network(Ni/Ce(F)g -PSC)

910 11 12 13 14 15100200300

Time (h)400500600

Temp. (oC)Catalytic performance
Ni-PSC < Ni/Ce-PSC < Ni/CeZ-PSC ≈ Ni/Ce(F)g-PSC
Coking tolerant!

Coking-tolerant paper-structured catalyst (PSC) for the dry reforming of methane (DRM) was studied.

♦Ni/Ce(F)g-PSC exhibited excellent catalytic performance comparable to the conventional best PSC (Ni-loaded
Ce0.4Zr0.6O2 (CeZ)-dispersed PSC prepared by co-precipitation (on paper synthesis)).
→ The flowerlike ceria-zirconia solid solution should be synthesized to further increase the catalytic performance.

700800