Benchmarking Nanoparticulate Metal Oxide Electrocatalysts for the Alkaline Water Oxidation ...

28 Pages·2015·2.19 MB·English

by  Suho Jung

Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A.
This journal is © The Royal Society of Chemistry 2015
Supplementary Information

Benchmarking Nanoparticulate Metal Oxide
Electrocatalysts for the Alkaline Water Oxidation
Reaction

Suho Jung, *a Charles C. L. McCrory, *a Ivonne M. Ferrer, ab Jonas C. Peters,*ab and
Thomas F. Jaramillo*ac

Section S1: Powder Diffraction Patterns ............................................................ S2
Section S2: SEM Images of Drop-casted Particles .......................................... S9
Section S3: The effect of oxide surface area on OER activity for NiO and
IrO particles ..................................................................................................................S15
2
Section S4: Electrical Conductivity of Metal Oxides ...................................S16
Section S5: Activity and Stability of Metal Oxides .......................................S17
Section S6: Tafel Plots .............................................................................................S18
Section S7: Comparisons of OER Activity for Particulate Films and Other
Deposited Films ............................................................................................................S25
Section S8: References .............................................................................................S28
(110)
(101)
(211)
(200(1) 11) (220)( 002) (310)( 112)( 301) (202)
(110) (101)
(211)
(200) ((202002)) ((131120)) (301) (202)
RuO, PDF#: 01-070-2662
2
IrO, PDF#: 01-088-0288
2
2θ

Figure S1. XRD patterns for noble metal oxides in rutile crystal structures. The broader peaks for
IrO -(i) indicate a small particulate size. Reference patterns from ICDD are also shown below for
2
matching and comparison.
(200)
(111)
(220)
(311) (222)
NiCoO
(200) 2
(111)
(220)
(311) (222)
(200) NiO
(111) (220) (311) (222)
CoO
NiCoO, PDF#: 00-003-0986
2
NiO, PDF#: 00-047-1049
CoO, PDF#: 01-074-2392
2θ

Figure S2. XRD patterns for first-row transition metal oxides in rock salt crystal structures. The
broader peaks of NiO-(i) indicate a small particulate size. Reference patterns from ICDD are also
shown below for matching and comparison.
(311)
(220) (222) (400) (511) (440)
(311) NiFe O
2 4
(220) (400) (511) (440)
(422)
(311) Fe2O3
(220) (400) (511) (440)
(111) (222) (422)
Co O
3 4
NiFeO, PDF#: 01-076-6120
2 4
FeO, PDF#: 01-078-6916
2 3
CoO, PDF#: 01-078-5618
3 4
2θ

Figure S3. XRD patterns for first-row transition metal oxides in spinel crystal structures. The
broader peaks of NiFe O indicate a small particulate size. Reference patterns from ICDD are also
2 4
shown below for matching and comparison.
(104)
(003) (012) (110)
(10(10)0 6) (015) (107) (018) (113) (116)
(003)
(104)
(006)
(101) (012) (015) (009(1) 07) (018)( 110)( 113)
LiNiO, PDF#: 00-062-0468
2
LiCoO, PDF#: 00-062-0420
2θ 2

Figure S4. XRD patterns for Li-based layered rhombohedral oxides. There are some peaks not
identified in the 2θ range of 20-35° for LiNiO , which may be attributed to an incomplete
2
calcination from the supplier. Reference patterns from ICDD are also shown below for matching
and comparison.
(110)
(012)
(202)
(300()1 22)
(101) (021) (214)
(003) (211(1) 13) (104) (220()0 24) (312)
(110) (104) LaNiO3
(024)
(214)
(012) (202) (300) (128)
(006) (122(1) 16) (018) (220()2 08) (134)
LaCoO
3
LaNiO, PDF#: 00-033-0711
3
LaCoO, PDF#: 00-025-1060
2θ 3

Figure S5. XRD patterns for La-based perovskite oxides. These two perovskites were synthesized
in the laboratory. Reference patterns from ICDD are also shown below for matching and
comparison.
(211) (202)
(103)
(224)
(112)
(101) (200) (004) (220) (105) (303()3 21) (400) (413)
(204) (312) (206()3 05)
(222)
(440)
(211) (400) (332) (431) (622)
(110)
(101) (211)
(200)( 111(2) 10) (220) (002) (310) (301)( 112)
(200)
(111) (220)
(311) (222)
MnO, PDF#: 01-080-0382
3 4
MnO, PDF#: 00-041-1442
2 3
MnO, PDF#: 01-071-0071
2
2θ MnO, PDF#: 01-075-6876

Figure S6. XRD patterns for various manganese oxides. All four manganese oxides exhibit
different crystal structures. Reference patterns from ICDD are also shown below for matching
and comparison.
Table S1. A summary of XRD characteristics for metal oxides
Oxides Crystal Str. System Space Lattice Parameters (Å) PDF number
group
a c
CoO Rock salt Cubic Fm-3m 4.2500 01-074-2392
Co O Spinel Cubic Fd-3m 8.1102 01-078-5618
3 4
NiO-(i) Rock salt Cubic Fm-3m 4.1771 00-047-1049
NiCoO Rock salt Cubic Fm-3m 4.2160 00-003-0986
2
NiFe O Spinel Cubic Fd-3m 8.3344 01-076-6120
2 4
Fe O Spinel Cubic Fd-3m 8.3562 01-078-6916
2 3
IrO -(i) Rutile Tetragonal P42/mnm 4.5051 3.1586 01-088-0288
2
RuO Rutile Tetragonal P42/mnm 4.4890 3.1049 01-070-2662
2
LiCoO Layered Rhombohedral* R-3m 2.8119 14.0334 00-062-0420
2
LiNiO Layered Rhombohedral* R-3m 2.8786 14.1984 00-062-0468
2
LaCoO Perovskite Rhombohedral R-3m 5.4410 13.0880 00-025-1060
3
LaNiO Perovskite Rhombohedral R-3m 5.4570 6.5720 00-033-0711
3
Scandium Cubic Ia-3 9.4091 00-041-1442
Mn O oxide type
2 3
MnO Rock salt Cubic Fm-3m 4.4460 01-075-6876
MnO Rutile Tetragonal P42/mnm 4.3983 2.8730 01-071-0071
2
Mn O Spinel Tetragonal I41/amd 5.7650 9.4420 01-080-0382
3 4
*indexed as hexagonal structure
NiO-(i) NiO-(ii)
CoO
NiCoO
2

Figure S7. SEM images of immobilized nanoparticles with Nafion onto glassy carbon
substrates – rock salt crystal structure based transition metal oxides. Note that NiO-(i)
and NiO-(ii) are shown in different scales.
Co O
3 4

Fe O
2 3

NiFe O
2 4

Figure S8. SEM images of immobilized nanoparticles with Nafion onto glassy carbon
substrates – spinel crystal structure based transition metal oxides