Digital.CSIC. Repositorio Institucional del CSIC

oai:digital.csic.es:10261/331796

62 pages. -- PDF file includes: 1. Experimental section. -- Figure S1. XRD patterns of pure ZIF-67 (a), Co(OH)2 (b) and Co3O4 (c). -- Figure S2. SEM images of Co3O4 single-shelled nanocages and EDS chemical mapping. -- Figure S3. SEM images of and EDS chemical mapping of CoP-HS (a); CoP2-HS (b); CoP3-HS (c). -- Figure S4. Nitrogen absorption–desorption isotherms and pore size distributions of three cobalt phosphides, CoP-HS (a); CoP2-HS (b); CoP3-HS (c). -- Figure S5. XPS spectra of the XPS full scan for CoP-HS, CoP2-HS and CoP3-HS. -- Figure S6. The CV curves of CoP-HS, CoP2-HS, and CoP3-HS obtained at the 1st (a), 3rd (b), 5th (c), and 10th (d) cycles at a scan rate of 10 mV/s in a 1.0 M KOH solution. -- Figure S7. The OER activities of CoP-HS, CoP2-HS and CoP3-HS were tested by both forward and reverse scan. -- Figure S8. (a) The CV of the CoPx. (b) The double layer capacitance (CDL) was determined as the half of the slope from the plot of the capacitive current vs. scan rate plot. -- Figure S9. Chronopotentiometry responses of activity stabilized CoPx in 1.0 M KOH in the catalytic turnover region. -- Figure S10. (a-c) OER LSV curves with (red) and without (blue) 100% iR drop correction. (d) Corresponding Tafel lines. -- Figure S11. SEM images of CoP-HS (a), CoP2-HS (b) and CoP3-HS (c) single-shelled nanocages after 100 h OER stability measurement. (d) The changed ratio of Co:P before and after stability test. -- Figure S12.SEM of post-OER CoP (a) before HCl wash, (b) after HCl washed. -- Figure S13. The LSV curves of CoP-HS, CoP2-HS, CoP3-HS, Co3O4-HS and Co(OH)2-HS measured in 1.0 M KOH solution toward OER at a scan rate 10 mV/s after activation by 50 CV cycles between 0.0 V and 0.85 V (vs. Hg/HgO) at a scan rate 50 mV/s. -- Figure S14. (a) The LSV curves of carbon paper measured in 1.0 M KOH toward HER at scan rate 10 mV/s. (b) The data of CoP-HS, CoP2-HS and CoP3-HS test in 1.0 M KOH. -- Figure S15. Chronopotentiometry responses of activity stabilized CoPx in 1.0 M KOH in the catalytic turnover region. -- Figure S16. (a-c) HER LSV curves with (red) and without (blue) 100% iR drop correction. (d) Corresponding Tafel lines. -- Figure S17. The CV curves of CoP-HS, CoP2-HS and CoP3-HS measured in 1.0 M KOH solution for 1st (a), 3rd (b), 5th (c), and 10th (d) cycles at a scan rate 10 mV/s. -- Figure S18. (a) The XPS spectra, and (b) the SEM image and EDS chemical mapping of CoP-HS after 100 h HER stability measurement in 1 M KOH. -- Figure S19. TEM images of CoP-HS after HER stability test (a). Elements mapping and SAED of CoP-HS after HER stability test (b-f). -- Figure S20. (a) The LSV curves of CoP-HS, CoP2-HS, CoP3-HS and Pt/C measured in 0.5 M H2SO4 toward HER at scan rate 10 mV/s. (b) The corresponding Tafel plots for the samples in 0.5 M H2SO4. (c) Nyquist plots of CoP-HS, CoP2-HS, CoP3-HS in 0.5 M H2SO4. (All the tests were taken on carbon paper). -- Figure S21. (a) The LSV curves of carbon paper measured in 0.5 M H2SO4 toward HER at scan rate 10 mV/s. (b) The data of CoP-HS, CoP2-HS and CoP3-HS test in 0.5 M H2SO4. -- Figure S22. The CV curves of CoP-HS, CoP2-HS and CoP3-HS measured in 0.5 M H2SO4 solution for 1st (a), 3rd (b), 5th (c), and 10th (d) cycles at a scan rate 10 mV/s. -- Figure S23. (a) The chronopotentiometry curve of CoP at the current density of -20 mA cm-2 for 100 h in 0.5 M H2SO4. (b) The SEM image and EDS chemical mapping (d) of CoP single-shelled nanocages after 100 h HER stability measurement. -- Figure S24. Overall water splitting activities of CoP||CoP and Pt/C||IrO2. -- Figure S25. (a, b, c, d, e, f) Corresponding levels of oxygen and hydrogen gas generated at 0 s, 200 s, 400 s, 600 s, 800 s, 1000 s. -- Figure S26. Optimized configuration of CoP-HS adsorbed with H. -- Figure S27. Optimized configuration of CoP2-HS adsorbed with H. -- Figure S28. Optimized configurations of CoP3-HS adsorbed with H. -- Figure S29. HER free energy changes of CoP-HS, CoP2-HS and CoP3-HS at P-sites and Co-site. in 0.5 M H2SO4. (c) P(2p) XPS spectra of CoP-HS after 100 h HER stability. -- Figure S30. The normalized LSV curves of CoP-HS, CoP2-HS, and CoP3-HS. -- Figure S31. The correlation between the HER free energy changes based on Co-sites of CoPx-HS and the normalized overpotential as well as Tafel slope measurement. -- Table S1. Elemental composition of Co and P in the different cobalt phosphides. -- Table S2. Comparison of the alkaline OER efficiency of those cobalt phosphides with other reported advanced cathodic materials. -- Table S3. Comparison of the alkaline HER efficiency of this CoP with other reported advanced cathodic materials. -- Table S4. Comparison of the acidic HER efficiency of this CoP with other reported advanced cathodic materials. -- Table S5. Comparison of the alkaline overall water-splitting efficiency of this CoP with other reported advanced bifunctional catalysts., Peer reviewed