Supplementary Material for "Unravelling the influence of shell thickness in organic functionalized Cu2O nanoparticles on C2+ products distribution in electrocatalytic CO2 reduction"

Supporting Information Unravelling the influence of shell thickness in organic functionalized Cu2O nanoparticles on C2+ products distribution in electrocatalytic CO2 reduction Jiajun Hu, Silvio Osella, Josep Albero* and Hermenegildo García* Table S1. Chemical composition of the samples under study, obtained from ICP-OES and elemental analysis. Angle (2 θ) CuODA1 (Å) CuODA2 (Å) CuODA3 (Å) CuODa4 (Å) 29.7400 3.0041 3.0001 3.0072 3.0109 36.6279 2.4535 2.4586 2.4594 2.4614 42.4921 2.1275 2.1211 2.1253 2.1286 61.6506 1.5045 1.5039 1.5059 1.5054 73.7942 1.2841 1.2834 1.2840 1.2855 Table S2. Chemical composition of the samples under study, obtained from ICP-OES and elemental analysis. Cu (wt.%) O (wt.%) C (wt.%) N (wt.%) H (wt.%) CuODA1 56.97 20.21 18.52 1.23 3.07 CuODA2 48.86 19.37 25.85 1.51 4.41 CuRNODA 45.28 13.51 33.87 1.73 5.61 CuRNODA4 32.28 8.46 48.26 2.73 8.32 CuODA2Wash 83.74 13.53 2.18 0.25 0.3 CuODa2 used 54.66 22.80 21.05 1.15 1.34 Table S3. Comparison of the eCO2RR performance of reported cathodic electrocatalysts with the activity of CuODA2 Entry Catalyst Electrolyte Potential/Current C1 FE (%) C2+ FE(%) H2 FE(%) Ref. 1 Cu dendrite CO2saturated 0.1 M CsHCO3 From -1.1 V to - 1.5 V vs. RHE (- 30 mA) 11 73 10 [1] 2 Cucurbit[6]urilsmodified Cu2O 0.5 M KHCO3 -0.7 V vs. RHE 94 0 6 [2] 3 Polyamideincorporated Cu 1 M KOH -0.97 V (433 mA/cm2) ~7 90 ~3 [3] 4 Histidinefunctionalized Cu 1 M KHCO3 -2 V vs. RHE < 5 77 21 [4] 5 Tetrahydrobipyridinefunctionalized Cu 1 M KHCO3 -0.83 V vs. RHE - 72 - [5] 6 CuODA2 0.1 M KHCO3 -0.9 V vs. RHE 15.7 73.3 11 This work 7 N-substituted pyridinium Cu 0.1 M KHCO3 -1.1 V vs. RHE - 7080 % - [6] 8 Phenanthroliniumderived Cu 0.1 M KHCO3 -4.4 V full-cell potential - 66 - [7] 9 FeTPP[Cl] inmobilized Cu 1 M KHCO3 -0.82 V vs. RHE - 41 - [8] 10 Dendritic polymer amine terminatedCu 1 M KOH -0.97 V vs. RHE 26 69 < 5 [9] 11 Bipyridine film on Cu 1 M KHCO3 -0.96 V vs. RHE 3 46 25 [10] 12 Thiazole functionalized Ag-Cu 0.5 M KHCO3 -4.5 V cell Voltage (250 mA/cm2) 10 80 5.3 [11] 13 Tannic acid modified Cu 1 M KOH -1.2 V vs. RHE 30 63.6 10 [12] Figure S1. PXRD patterns of CuODA1, CuODA2, CuODA3 and CuODA4. The standard pattern of Cu2O (PDF #05-0667) is also included. Figure S2. TEM images of CuODA1 (a), CuODA2 (b), CuODA3 (c) and CuODA4. Insets show histogram of particle size distribution and the average particle size. Figure S3. ATR-FTIR spectra of ODA, CuRN1, CuRN2, CuRN3 and CuRN4. Figure S4. Cu LMM Auger spectra of CuODA1 (a), CuODA2 (b), CuODA3 (c) and CuODA4 (d). Figure S5. Liner Sweep Voltammetry (LSV) of CuODA1 (a), CuODA2 (b), CuODA3 (C) and CuODA4 (d) in N2-saturated (dashed) and CO2-saturated (solid) 1 M KHCO3 electrolyte. Figure S6. PXRD patterns of CuODA2 and CuODA2-wash. Figure S7. TEM images of CuODA2-wash samples acquired at different magnifications. Figure S8. H2O hydrophobicity test of CuODA2 and CuODA2-wash. It can be seen that CuODA2-wash precipitates at the bottom, while CuODA2 floats on water after 2 h. Figure S9. Cyclic voltammograms of the samples at different scan rates from 10 to 80 mV/s. Figure S10. Capacitive current as scan rate function of the different samples. The CDL obtained is indicated for each sample. Figure S11. CO2 adsorption isotherms at 25 oC of CuODA2 (black) and CuODA2-wash (red). Figure S12. In situ electrochemical Raman spectra of CuODA2 (a and b), CuODA4 (c and d) and CuODA2-wash (e and f) obtained at open circuit potential (black) and at cathode potential of -0.9 V (red). Laser excitation 785 nm. Figure S13. Nyquist plots of CuODA1 (a), CuODA2 (b), CuODA2-wash (c), CuODA3 (d) and CuODA4 (e) collected at 20 different potentials between -0.2 to -0.8 V vs. RHE in 0.03 V increments. The spectra were collected from 0.5 Hz to 30 kHz at 10 points per decade. CO2saturated 1M KHCO3 electrolyte. Pt wide and KCl-saturated Ag/AgCl were used as counter and reference electrodes, respectively. Figure S14. a) Nyquist plot of CuODA2 measured at -0.7 V vs. RHE in the range from 0.5 Hz to 30 kHz. b) Equivalent circuit used to fit the obtained experimental data. Figure S15. (a) Stepwise potential profile applied to the working electrode in pulsed voltammetry experiments. (b-f) Pulse responses for CuODA1 (b), CuODA2 (c), CuODA3 (d), CuODA4 (e) and CuODA2-wash (f).