Comprehensive Impedance Spectroscopy Analysis on the Electrocatalytic Reduction of 5-Hydroxymethylfurfural

# Dataset of "Comprehensive Impedance Spectroscopy Analysis on the Electrocatalytic Reduction of 5-Hydroxymethylfurfural"

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## GENERAL INFORMATION----------------------

1. Dataset title: "Comprehensive Impedance Spectroscopy Analysis on the Electrocatalytic Reduction of 5-Hydroxymethylfurfural"

2. Authorship:      Name: Jose Solera-Rojas      Institution: Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castelló, Spain    ORCID: 0000-0003-3513-7069

    Name: David Carvajal    Institution: Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castelló, Spain    ORCID: 0000-0002-8450-2563

    Name: Antonio Guerrero    Institution: Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castelló, Spain    ORCID: 0000-0001-8602-1248

    Name: Carmen Mejuto    Institution: Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castelló, Spain    ORCID: 0000-0002-4432-5697

    Name: Elena Más-Marzá    Institution: Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castelló, Spain    Email:         ORCID: 0000-0002-2308-0635

    Name: Francisco Fabregat-Santiago    Institution: Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castelló, Spain    Email:      ORCID: 0000-0002-7503-1245

## FILE DESCRIPTION--------------### Figure 2- Fig2b.txt : Cyclic voltammetry (CV) for the reduction of HMF, BHMF, 5-MF and MFA. A 20 mM of each organic molecule in a solution of 0.5 M NaH2PO4 (pH = 4.1) was used.- Fig2c.txt : Conversion of HMF and yields of BHMF, MFA, DMF and 5-MF. - Fig2d.txt : Faradaic Efficiency (FE) for the electroreduction of 20 mM HMF at pH = 4.1.

### Figure 3- Fig3a.txt : Uncorrected J-V curve taken at the end of IS measurements without and with all the organic molecules in this study- Fig3b.txt : Corrected J-V curve taken at the end of IS measurements without and with all the organic molecules in this study- Fig3c.txt : Faradaic Efficiencies for Glycerol oxidation electrolysis at 5 mA cm^-2.- Fig3d.txt : Nyquist plots in the absence and presence of each organic molecule at -0.65 V vs. RHE.

### Figure 4- Fig4a.txt : Results obtained from fitting the IS data Cdl- Fig4b.txt : Results obtained from fitting the IS data Rct- Fig4c.txt : Results obtained from fitting the IS data Css- Fig4d.txt : Results obtained from fitting the IS data Rss- Fig4e.txt : Results obtained from fitting the IS data L- Fig4f.txt : Results obtained from fitting the IS data tau

### Figure S3- FigS3a.txt : Cyclic voltammetry of 5-MF at different concentrations (20, 40 and 80 mM) in a solution of 0.5 M NaH2PO4 (pH = 4.1) at a 5 mV/s scan rate.- FigS3a.txt : Cyclic voltammetry of HMF at different concentrations (20, 40 and 80 mM) in a solution of 0.5 M NaH2PO4 (pH = 4.1) at a 5 mV/s scan rate.- FigS3a.txt : Cyclic voltammetry of BHMF at different concentrations (20, 40 and 80 mM) in a solution of 0.5 M NaH2PO4 (pH = 4.1) at a 5 mV/s scan rate.- FigS3a.txt : Cyclic voltammetry of MFA at different concentrations (20, 40 and 80 mM) in a solution of 0.5 M NaH2PO4 (pH = 4.1) at a 5 mV/s scan rate.

### Figure S4- FigS4a.txt : HPLC chromatograms for HMF, BHMF, 5-MF, MFA and DMF from commercially available products at (a) 294 nm, (b) 285 nm and (c)-(d) 222 nm. The solution from DMF was prepared in cyclohexane and diluted in CH3CN.- FigS4b.txt : HPLC chromatograms for HMF, BHMF, 5-MF, MFA and DMF from commercially available products at (a) 294 nm, (b) 285 nm and (c)-(d) 222 nm. The solution from DMF was prepared in cyclohexane and diluted in CH3CN.- FigS4c.txt : HPLC chromatograms for HMF, BHMF, 5-MF, MFA and DMF from commercially available products at (a) 294 nm, (b) 285 nm and (c)-(d) 222 nm. The solution from DMF was prepared in cyclohexane and diluted in CH3CN.- FigS4d.txt : HPLC chromatograms for HMF, BHMF, 5-MF, MFA and DMF from commercially available products at (a) 294 nm, (b) 285 nm and (c)-(d) 222 nm. The solution from DMF was prepared in cyclohexane and diluted in CH3CN.

### Figure S5- FigS5a.txt : Calibration curves for (a) HMF (285 nm), (b) BHMF (222 nm), (c) MFA (222 nm), (d) 5-MF (294 nm) and (e) DMF (222 nm).- FigS5b.txt : Calibration curves for (a) HMF (285 nm), (b) BHMF (222 nm), (c) MFA (222 nm), (d) 5-MF (294 nm) and (e) DMF (222 nm).- FigS5c.txt : Calibration curves for (a) HMF (285 nm), (b) BHMF (222 nm), (c) MFA (222 nm), (d) 5-MF (294 nm) and (e) DMF (222 nm).- FigS5d.txt : Calibration curves for (a) HMF (285 nm), (b) BHMF (222 nm), (c) MFA (222 nm), (d) 5-MF (294 nm) and (e) DMF (222 nm).- FigS5e.txt : Calibration curves for (a) HMF (285 nm), (b) BHMF (222 nm), (c) MFA (222 nm), (d) 5-MF (294 nm) and (e) DMF (222 nm).

### Figure S6- FigS6.txt : HPLC chromatogram for the chronoamperometry experiment at -0.55 V vs. RHE and 294 nm for the detection of 5-MF.

### Figure S8- FigS8.txt : HPLC chromatogram from the top organic phase from an experiment of 20 mM 5-MF at -0.65 V vs. RHE with a charge limit of 38.6 C. DMF shows a retention time of 21.57 min, while the signal at 12.80 min corresponds to 5-MF partially solubilize in the cyclohexane layer

### Figure S9- FigS9.txt : HPLC chromatogram at 222 nm from a chronocoulometric reaction of 20 mM HMF at -0.85 V vs. RHE 

### Figure S10- FigS10.txt : Stability test of 20 mM standard solution of HMF, BHMF, MFA and 5-MF in a 0.5 M NaH2PO4 (pH = 4) solution for 12 h, quantified by HPLC

### Figure S12- FigS10a.txt : Bode plots of impedance spectra in Figure 3c for w/o organic molecule- FigS10b.txt : Bode plots of impedance spectra in Figure 3c for 5-MF- FigS10c.txt : Bode plots of impedance spectra in Figure 3c for HMF- FigS10d.txt : Bode plots of impedance spectra in Figure 3c for BHMF- FigS10e.txt : Bode plots of impedance spectra in Figure 3c for MFA

### Figure S13- FigS13.txt : Impedance spectra for HMF change with voltage and so it does the equivalent circuit used to fit the experimental data.

### Figure S14- FigS14a,b,c,d.txt : Chronoamperometries of Cu electrodes with the different electrolytes. Peaks observed in the transition between potentials (blue arrows) are associated to the charging of a large capacitor, in our case the surface state capacitor. In the case of MFA this peak is may not be clearly observed as the Css attains large values at voltages in which high current is crossing the electrochemical cell.