Laser-generated high entropy metallic glass nanoparticles as bifunctional electrocatalysts

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Laser-generated high entropy metallic glass nanoparticles as bifunctional electrocatalysts

Jacob Johny¹, Yao Li¹, Marius Kamp², Oleg Prymak³, Shun-Xing Liang¹, Tobias Krekeler⁴, Martin Ritter⁴, Lorenz Kienle², Christoph Rehbock¹, Stephan Barcikowski¹ (✉),

and Sven Reichenberger¹

1 Technical Chemistry I and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Essen 45141, Germany

2 Institute for Materials Science, Synthesis and Real Structure, Kiel University, Kiel 24143, Germany

3 Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Essen 45141, Germany

4 Electron Microscopy Unit, Hamburg University of Technology, Hamburg 21073, Germany

Supporting information to https://doi.org/10.1007/s12274-021-3804-2

Address correspondence to stephan.barcikowski@uni-due.de

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Table S1 XPS fitting parameters

Cr 2p3/2

Cr⁰ Cr³⁺ (O^2-) Cr³⁺ (OH^-)

min max ΔCr⁰ ΔCr⁰

Pos. Constr. / eV 574.1 574.3 2.4 3.0

FWHM Constr. / eV 1.0 3.0 - - -

Co 2p3/2

Co⁰ Co²⁺ Co³⁺

min max ΔCo⁰ ΔCo⁰

Pos. Constr. / eV 777.7 778.9 3.4 1.7

FWHM Constr. / eV 1.0 3.0 - -

Fe 2p3/2

Fe⁰ Fe²⁺ Fe³⁺ Fe³⁺

(OOH)

min max ΔFe⁰ ΔFe⁰ ΔFe⁰

Pos. Constr. / eV 706.5 707.5 2.6 4.1 5.0

FWHM Constr. / eV 1.0 3.0 - - -

Ni 2p3/2

Ni⁰ Ni²⁺ (O^2-) Ni²⁺ (OH^-)

min max ΔNi⁰ ΔNi⁰

Pos. Constr. / eV 852.4 853.0 1.1 3.2

Mn 3d5/2

Mn²⁺ Mn⁴⁺ Mnsat.

min max ΔMn²⁺ min max

Pos. Constr. / eV 641.3 641.5 0.7 6460 648.0

FWHM Constr. / eV 1.0 3.0 - 1.0 3.0

Mo 3d5/2

Mo⁰ or Mo²⁺ Mo⁴⁺ Mo 3d3/2

min max ΔMo ΔMo 3d5/2

Pos. Constr. / eV 227.8 228.2 0.8 3.15

Lattice oxygen Carbonic oxygen

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Table S2 Chemical composition of single NPs, quantified by STEM-EDX area measurements.

Sample Cr17.5Co17.5Fe17.5Ni17.5Mn30 Cr16Co16Fe16Ni16Mn30Mo06

Element at%

NP 1 NP 2 NP 3 NP 1 NP 2 NP 3 NP 4 NP 5

Cr 25.8 19.2 34.9 19.9 13.8 14.7 30.5 36.5

Mn 11.6 20.5 10.4 7.7 35.8 10.0 5.6 1.7

Fe 22.7 20.3 19.2 17.9 22.5 27.8 24.5 22.2

Co 20.3 19.0 17.4 24.6 13.1 19.4 15.9 15.6

Ni 19.6 21.1 18.0 19.2 14.6 23.0 11.2 8.5

Mo - - - 10.6 0.3 5.1 12.3 15.6

Fig. S1 HAADF-STEM image of two

Cr

10

Co

10

Fe

10

Ni

10

Mn

30

Mo

30 NPs. EDX elemental maps show the formation of a Mn-rich and a Mo-rich NP. C-K, O-K, Cr-K, Mn-k, Ni-K, Co-K and Mo-L lines were used for imaging and quantification.

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Fig. S2 SEM-EDX maps of Cr-K, Co-K, Fe-K, Ni-K, Mn-K, Mo-L and O-K lines of the representative Cr16Co16Fe16Ni16Mn30Mo06 HEA ablation target showing the distribution of the elements on the target surface.

Table S3 Chemical composition of the HEA ablation targets obtained from EDX measurements.

Composition

At.% O/M

ratio

Cr Co Fe Ni Mn Mo O

Cr17.5Co17.5Fe17.5Ni17.5Mn30

Area#1 18.7 24.3 24.3 18.9 13.8 - 0.13 Area#2 20.0 21.9 24.3 18.9 14.9 - 0.00

Cr16Co16Fe16Ni16Mn30Mo6

Area#1 14.8 20.0 21.0 20.5 12.5 11.2 0.23 Area#2 15.6 19.7 21.1 14.8 13.3 15.5 0.43

Area#1 14.4 18.4 17.4 22.5 9.1 18.2 0.35 Area#2 14.8 19.0 19.5 18.1 8.2 20.4 0.34

Area#1 10.3 10.5 12.0 10.3 13.2 43.7 0.28 Area#2 11.0 9.8 10.8 9.5 19.0 39.9 0.41

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Table S4 Chemical composition of the HEA ablation targets obtained from XRF measurements.

Composition

At.%

Cr Co Fe Ni Mn Mo

Cr17.5Co17.5Fe17.5Ni17.5Mn30 18.0 18.8 21.8 20.4 20.5 - Cr16Co16Fe16Ni16Mn30Mo6 14.1 14.8 15.3 16.5 27.2 9.7 Cr14Co14Fe14Ni14Mn30Mo14 12.0 13.1 14.7 15.6 24.0 19.3 Cr10Co10Fe10Ni10Mn30Mo30 8.1 9.1 10.1 10.3 19.7 40.9

Fig. S3 HRTEM micrograph of Cr16Co16Fe16Ni16Mn30Mo6 NPs showing the graphitic C-shells around the NPs, verified by fast Fourier transforms of the marked area (inset).

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Fig. S4 HRTEM micrographs of (a) Cr14Co14Fe14Ni14Mn30Mo14 and (b) Cr10Co10Fe10Ni10Mn30Mo30

NPs, (c,d) SAED patterns, and (e,f) EDX elemental line scans of the respective samples.

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Fig. S5 XRD diffractogram of Cr16Co16Fe16Ni16Mn30Mo06 HEMG NPs after centrifugation to remove extra-large NPs, showing only amorphous phase without any fcc reflections.

Fig. S6 Interplanar spacing corresponding to the (111) and (200) fcc crystal planes showing gradual increase with increase in the Mo content.

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Fig. S7 (a) 3 repeated OER and (b) ORR measurements of the Cr16Co16Fe16Ni16Mn30Mo06 NPs.

Fig. S8 (a) Tafel slopes extracted from the OER LSV curves of Cr17.5Co17.5Fe17.5Ni17.5Mn30, Cr16Co16Fe16Ni16Mn30Mo06, Cr14Co14Fe14Ni14Mn30Mo14, and Cr10Co10Fe10Ni10Mn30Mo30 HEMG NPs.

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Fig. S9 Cyclic performance of the (a) Cr17.5Co17.5Fe17.5Ni17.5Mn30, (b) Cr16Co16Fe16Ni16Mn30Mo06, (c) Cr14Co14Fe14Ni14Mn30Mo14, and (d) Cr10Co10Fe10Ni10Mn30Mo30 HEMG NPs during the OER in N2- saturated 0.1M NaOH.

Fig. S10 Cyclic voltammograms of the (a) Cr17.5Co17.5Fe17.5Ni17.5Mn30, (b) Cr16Co16Fe16Ni16Mn30Mo06, (c) Cr14Co14Fe14Ni14Mn30Mo14, and (d) Cr10Co10Fe10Ni10Mn30Mo30 HEMG NPs during the ORR in O2- saturated 0.1M NaOH.