Mo3+ hydride as the common origin of H2 evolution and selective NADH regeneration
in molybdenum sulfide electrocatalysts
Item Type Article
Authors Bau, Jeremy;Emwas, Abdul-Hamid M.;Nikolaienko, Pavlo;Aljarb, Areej A.;Tung, Vincent;Rueping, Magnus
Citation Bau, J. A., Emwas, A.-H., Nikolaienko, P., Aljarb, A. A., Tung, V.,
& Rueping, M. (2022). Mo3+ hydride as the common origin of H2 evolution and selective NADH regeneration in molybdenum sulfide electrocatalysts. Nature Catalysis. https://doi.org/10.1038/
s41929-022-00781-8 Eprint version Post-print
DOI 10.1038/s41929-022-00781-8
Publisher Springer Science and Business Media LLC
Journal Nature Catalysis
Rights Archived with thanks to Nature Catalysis Download date 2024-01-14 19:22:37
Link to Item http://hdl.handle.net/10754/678133
Mo 3 + hydride as the common origin of H 2
evolution and selective NADH regeneration in molybdenum sulfide electrocatalysts
In the format provided by the authors and unedited
Supplementary information
https://doi.org/10.1038/s41929-022-00781-8
1
Supplementary Information
Mo
3+hydride as the common origin of H
2evolution and selective NADH regeneration in molybdenum sulfide electrocatalysts
Jeremy A. Bau1*, Abdul-Hamid Emwas2, Pavlo Nikolaienko1, Areej A. Aljarb3,1, Vincent Tung1, Magnus Rueping1*
1KAUST Catalysis Center, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
2Imaging and Characterization Laboratory, KAUST, Thuwal, Saudi Arabia
3Department of Physics, King Abdulaziz University, Jeddah, Saudi Arabia
2
Supplementary Fig. 1. Diagram of the electrochemical EPR setup.
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Supplementary Figure 2. Easyspin simulations of EPR spectra.
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Supplementary Table 1. EPR parameters of Mo3+ hydride from this work compared to literature values.
Parameter giso Aiso (1H) / MHz This work 2.014 34.5 Prior et al.7 2.016 37.8–40.4 Baya et al.8 2.016 31.95 Kinney et al.9 Axial 30.5
Tsai et al.10 1.9825 45.48
5
Supplementary Fig. 3. Examples of electrochemical behavior of a-MoSx. Traces of a- MoSx scanned using (a-c) linear sweep voltammograms in 0.5 M H2SO4 (scanned at 1 mV s−1) and (d-f) 0.2 M Bu4N PF6. The overpotentials from (a-c) and the peak areas in (d- f) are used to generate Figure 2c.
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Supplementary Fig. 4. Electrochemical behavior of MoS2 prepared by hydrothermal synthesis. Example organic sweeps in 0.2 M Bu4N PF6 (left) and linear sweep voltammograms in 0.05 M H2SO4 (right) of MoS2 electrodes prepared by autoclave synthesis.
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10 20 30 40 50 60 70 80
(002)
(110)
2-theta / degrees (100)
Supplementary Fig. 5. XRD pattern of MoS2 electrodes prepared by autoclave synthesis.
The pattern matches well to reported patterns for MoS2 nanosheets.11
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Supplementary Fig. 6. Electron micrographs of a-MoSx and autoclave-prepared (hydrothermal) MoS2.
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Supplementary Figure 7. X-ray photoelectron spectra of prepared Mo sulfides. Mo3d and S2p for a-MoSx and autoclave-prepared (hydrothermal) MoS2.
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Supplementary Fig. 8. Electrochemical behavior of defect-free MoS2 films. Example
organic sweeps in 0.2 M Bu4N PF6 (left) and linear sweep voltammograms in 0.05 M H2SO4 (right) of epitaxially-grown single-crystal MoS2 films.
11
Supplementary Fig. 9. NMR spectrum of NMN starting material.
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Supplementary Fig. 10. Full 13C NMR spectrum of Figure 4b. The reaction was run in D2O. Marked peaks correspond to splitting arising from CDH groups.
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Supplementary Fig. 11. Full 13C NMR spectrum of Figure 4c. The reaction was run in H2O. Marked peaks are the peaks that are split in the case of CDH, but here are CH2.
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Supplementary Fig. 12. Full 2H NMR spectrum of Figure 4d. The reaction was run in D2O.
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Supplementary Fig. 13. Full 1H NMR spectrum of Figure 4e. The reaction was run in D2O.
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Supplementary Fig. 14. Full 1H NMR spectrum of Figure 4f. The reaction was run in H2O.
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Supplementary Fig. 15. UHPLC and mass spectra (experimental and theoretical) of NAD dimer in NAD reduced by a-MoSx in 0.1 M ammonium acetate (pH 9). Note that, while a mass product of a similar mass to the dimer was detected in Run 2 (and only in Run 2), additional isotopic isomers are not detected, possibly as a consequence of the low concentration of dimer. Therefore, the hypothesized species cannot even be truly confirmed as being the dimer.
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Supplementary Fig. 16. UHPLC of NAD dimer-DBA ion pair in NAD reduced by a-MoSx
in 0.1 M ammonium acetate (pH 9). The MS filter values were the same used in Extended Data Figure 20.
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Supplementary Fig. 17. UHPLC and mass spectra (experimental and theoretical) of NADH-DBA ion pair in NAD reduced by a-MoSx in 0.1 M ammonium acetate (pH 9).
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Supplementary Fig. 18. UHPLC and mass spectra (experimental and theoretical) of NADH in NAD reduced by a-MoSx in 0.1 M ammonium acetate (pH 9).
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Supplementary Fig. 19. UHPLC and experimental mass spectrum of NAD dimer in NAD reduced by a-MoSx in 0.1 M ammonium acetate (pH 9).
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Supplementary Fig. 20. UHPLC and experimental mass spectrum of NAD dimer-DBA ion pair in NAD reduced by a-MoSx in 0.1 M ammonium acetate (pH 9).
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Supplementary Fig. 21. 1H NMR spectrum of NADH regenerated by a-MoSx. Regions of interest corresponding to the C2 region highlighted.
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1 2 3 4
0 2 4 6 8 10
Faradaic Efficiency / %
Time / h
Supplementary Fig. 22. Faradaic efficiency measurements of the reaction featured in Fig.
5c. FE was calculated by combining the % reaction of both the NADH and the benzaldehyde at each time point and comparing to the overall reduction current up to that point converted to moles of electrons by dividing by Faraday’s constant. Error bars indicate the standard deviations of the triplicate measurements that were used to derive these values.
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Supplementary Fig. 23. XPS of maleimide functionalized Mo sulfide. N1s (left) and S2p (right) XPS of 6-maleimidohexanoic acid-functionalized a-MoSx electrodes. N1s at 400 eV corresponds to the N of maleimide.
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Supplementary Table 2. Quantification of N to S from Supplementary Fig. 23.
Peak(s) Area RSF Composition Ratio
S2p 4528.6 1.677 2700.4 4.19
N1s 1159.2 1.8 644.0 1
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Supplementary Fig. 24. Effect of maleimide on reduction behavior of a-MoSx. Ultrathin electrodes (5 cycle depositions) are compared in neutral and acidic electrolytes to their maleimide-functionalized counterparts. Inset. Average overpotentials (at −10 mA cm−2) of ultrathin a-MoSx electrodes compared to those functionalized with maleimide derivative.
Error bars indicate the standard deviations of the overpotentials from triplicate measurements.
-0.5 -0.4 -0.3 -0.2 -0.1 0.0 -10
-8 -6 -4 -2 0
0.1 M pH 7 KPi
Control Maleimide 0
200 400 600
/ mV @ 10 mA cm2
j / mA cm2
E iR / V vs. RHE
a-MoSx thin layer
a-MoSx thin layer with maleimide
-0.26 -0.24 -0.22 -0.20 -0.18 -0.16 -10
-8 -6 -4 -2 0
Control Maleimide 150
200 250 300
/ mV @ 10 mA cm2
j / mA cm2
E iR / V vs. RHE
a-MoSx thin layer
a-MoSx thin layer with maleimide 0.5 M H2SO4
