____________________Dataset for Cobalt and nickel doped WSe2 as efficient electrocatalysts for water splitting and as cathodes in hydrogen evolution reaction PEM water electrolysis____________________ Last updated: 2024-01-10 ______Contact______ * Antonia Kagkoura * ORCID: 0000-0002-6294-7887 * Dept. of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Prague * Technicka 5, 166 28, Prague 6, Czech Republic ______Principal Investigator______ * Karel Bouzek * ORCID: 0000-0002-1391-4448 * Dept. of Inorganic Technology, Faculty of Chemical Technology, University of Chemistry and Technology, Prague * Technicka 5, 166 28, Prague 6, Czech Republic ______Data manager or custodian______ * Michal Carda * ORCID: 0000-0002-3061-3751 * Dept. of Inorganic Technology. Faculty of Chemical Technology, University of chemistry and Technology, Prague * Technicka 5, 166 28, Prague 6, Czech Republic ______License______ *Dataset for Cobalt and nickel doped WSe2 as efficient electrocatalysts for water splitting and as cathodes in hydrogen evolution reaction PEM water electrolysis © 2024 by Antonia Kagkoura is licensed under CC BY *license information: https://creativecommons.org/licenses/by/4.0/ ------------------------------------------------------------------------------------------------ ______About the dataset______ Efficient electrocatalysts are crucial for water splitting and fuel cells. Using cheap alternatives that can improve reaction kinetics is essntial for advancing fuel cell technology. Although, tungsten diselinide (WSe2) is promising for electrocatalysis is not fully explored, especially in oxygen evolution and in applications such as polymer electrolyte membrane water electrolyzer. In this work, we used a simple approach to dope WSe2 with cobalt and/or nickel atoms. The doped material was subsequently tested for hydrogen evolution reaction and oxygen evolution reaction. Accordingly, the two electrocatalysts are highly active and stable, affording low overpotentials comparable to those of noble metals. The effective introduction of heteroatoms causes the retention of coordination vacancies, furnishing active catalytic sites that enhanced electrocatalytic performance both in activity and charge transfer. Moreover, both doped materials show excellent performance and stability as cathode electrocatalysts in the polymer electrolyte membrane water electrolyzer with great promise for real-world applications. ______Methods of data collection______ * General Chemicals, reagents, and solvents were purchased from Sigma-Aldrich and used without further purification. SEM. The morphology of analyzed materials was investigated using scanning electron microscopy (SEM) with a Tescan MAIA-3 Field Emission Gun Scanning Electron Microscope (FEG-SEM). To conduct the measurements, the samples were placed on a carbon conductive tape. SEM and measurements were carried out, respectively, at 5 acceleration voltage. * TEM A JEOL monochromated ARM200F transmission electron microscope (TEM) operated at 200 kV was used for scanning transmission electron microscopy (STEM) and STEM-EDS analysis. The TEM is equipped with a CEOS probe abberation corrector, a CEOS image abberation corrector and a double silicon drift detector (SDD) for EDS. High angle annular dark field (HAADF) STEM imaging was used to directly visualize atomic structure of the crystals. The beam convergence half-angle and collectioin inner half-angle are ~ 27 mrad and 55 mrad, respectively. The resolution for STEM imaging is ~ 0.8 Å. *STEM-EDS STEM-EDS was used to map spatial distribution of elements at the nanometer and atomic scales. TEM specimens were prepared by manually grinding bulk crystals in IPA for 15 min in a mortar. The resultant solution with nanocrystals was drop-casted on holey carbon coated Cu grid and dried in air. *XPS High resolution X-ray photoelectron spectroscopy (XPS) was performed using an ESCAProbeP spectrometer (Omicron Nanotechnology Ltd, Germany) with a monochromatic aluminium X-ray radiation source (1486.7 eV). Wide-scan surveys of all elements were performed, with subsequent high-resolution scans of the C 1s and O 1s. Relative sensitivity factors were used to evaluate the carbon-to-oxygen (C/O) ratios from the survey spectra. The samples were placed on a conductive carrier made from a high purity silver bar. An electron gun was used to eliminate sample charging during measurement (1–5 V). Raman spectroscopy. inVia Raman microscope (Renishaw, England) in backscattering geometry with CCD detector was used for Raman spectroscopy. DPSS laser (532 nm, 50 mW) with applied power of 5 mW and 50x magnification objective was used for the measurement. Instrument calibration was achieved with a silicon reference which gives a peak position at 520 cm−1 and a resolution of less than 1 cm-1. The samples were suspended in deionized water (1 mg/ml) and ultrasonicated for 10 min. The suspension was deposited on a small piece of silicon wafer and dried. *Electrochemical measurements The electrochemical characterization by means of cyclic linear sweep voltammetry was performed using an Autolab PGSTAT 204 (Metroohm, Switzerland). A standard three-compartment electrochemical cell was used equipped with an RDE with a glassy carbon disk (geometric surface area: 0. 196 cm2) as a working electrode, graphite rod as a counter-electrode, and Hg/HgSO4 (0.5 M K2SO4) as reference electrode. HER LSV measurements were performed in N2-saturated aqueous 0.5 M H2SO4 solution at room temperature. For preparing the catalyst ink, catalytic powder (4.0 mg) was dissolved in a mixture (1 mL) of deionized water, isopropanol, and 5% Nafion (v/v/v = 4:1:0.02) followed by sonication for 30 min before use. The working electrode was polished with alumina suspension, washed with deionized water, and finally sonicated in double-distilled water before casting 8.5 μL aliquots of the electrocatalytic ink on the electrode’s surface. Finally, electrochemical impedance spectroscopy (EIS) measurements were acquired from 105 to 10−1 Hz with an AC amplitude of 0.01 V. *Membrane-electrode assembly (MEA) preparation and electrochemical characterization in a two-electrode PEM cell MEA devices were prepared by pressing the anode and cathode with a commercial Nafion N-115 polymer electrolyte membrane three times at 130 °C for 2 minutes using a Stahls Hotronix 6″ × 6″ heat press. Before the assembly of the device, the membranes were activated by heating them at 80 °C for 1 h in H2O2 – 3% V/V, deionized water (18.2 MΩ●cm), 0.5 M H2SO4, one more time in water and stored in the same solvent until usage. Both, anode and cathode electrodes, were deposited by the air gun-spraying technique using N2 as carrier gas, and a high porosity platinized-Ti fiber felt (at 100 °C) or carbon paper (CP-39BB, at 70 °C) as gas diffusion layers, respectively. For the anode, the ink used consisted in a IrO2 particles dispersion with a concentration of 10.6 mg mL-1 in a solvent mixture of 2-propanol, water and a Nafion solution (5 % wt in ethanol, Nafion D520) in a 84.9:9.7:5.4 % V/V ratio; while for the cathode, the catalyst ink consisted in 5.5 mg mL-1 of WSe2, Ni- WSe2, Co-WSe2 or Pt-C (20%, as reference) dispersed in a 2-propanol/water/Nafion D520 (88.1:10.04:1.86 % V/V) mixture. Finally, the electrode´s catalyst loading was set to ≈2.5 mg cm-2 for the anode, ≈0.8 mg cm-2 for the WSe2-based cathode catalyst and ≈0.4 mg cm-2 of pure Pt for the reference MEA. The electrochemical performance of freshly prepared MEA devices was evaluated using a Scribner-Electrolyzer test system 600, working at 80 °C and atmospheric pressure conditions, with a feed flow of water at the positive side of 100 mL min-1 and no N2 flow at the negative side. All the MEAs were activated, before any electrochemical characterization, by applying a constant current of 100 mA cm-2 during 30 min to open channels in the electrocatalytic films for the diffusion of the reaction precursors and increase the release of gases towards the flow fields in the PEM cell. After the activation step, I-V curves were obtained through galvanostatic step sweep polarization from 0.04 mA to 10 A, at a scan rate of 3 mA per step, a duration of 5 s step, an acquisition time of 5 s per point and, in the potential window of 0.3 to 2.1 V. Electrochemical impedance spectroscopy experiments were performed right after the polarization curves at 0.5 A and an alternant perturbation of the 10% in the frequency range of 50 kHz to 0.1 Hz; where the Ohmic resistance (Rs) and the charge transfer resistance (Rct) were calculated by fitting the resulting electrochemical spectra with an equivalent electrical circuit. Finally, Information about the stability of the WSe2 based materials was obtained after keep the devices at a constant voltage of 1.9 V for 24 h and tracking the changes on the devices performance with the polarization curves and EIS characterization at the same conditions as stated above. *Preparation of WSe2 Tungsten hexacarbonyl (1 mmol) and selenium powder (2 mmol) were dissolved in 30 mL DMF and the resulting suspension was transferred into a 50 mL Teflon-lined stainless-steel autoclave reactor and heated at 200 °C for 13 h. After the autoclave was cooled to room temperature, the resulting suspension was centrifuged at 10000 rpm with DMF (2 times), water (3 times) and methanol (3 times). *Preparation of Co-WSe2 Preparation of Co-WSe2: Initially, a mixture comprising 50.6 mg of cobalt acetate tetrahydrate and 36 mg of thiourea was prepared in 1 ml of water and allowed to stand overnight, resulting in the formation of the Co ion complex, Co(thiourea)42+. Subsequently, this solution of the Co thiourea complex was introduced into 50 ml of a stabilized WSe colloid solution (with a concentration of 1 mg ml−1 and containing 30 v/v% isopropanol/water with 50 mg of polyvinylpyrrolidone). The resulting dispersion was then transferred to a 100 ml vessel autoclave and subjected to hydrothermal treatment at 160°C for 24 hours. *Preparation of Ni-WSe2: A mixture comprising 50 mg of cobalt acetate tetrahydrate and 36 mg of thiourea was prepared in 1 ml of water and allowed to stand overnight, resulting in the formation of the Ni ion complex, Ni(thiourea)42+. Subsequently, this solution of the Co thiourea complex was introduced into 50 ml of a stabilized WSe colloid solution (with a concentration of 1 mg ml−1 and containing 30 v/v% isopropanol/water with 50 mg of polyvinylpyrrolidone). The resulting dispersion was then transferred to a 100 ml vessel autoclave and subjected to hydrothermal treatment at 160°C for 24 hours. ______Methods of data processing______ The dataset contains mostly raw exported data. All data processing is described in the respective data collection section. ------------------------------------------------------------------------------------------------ ______File formats______ * Cyclic voltammetry - exported CSV * X-ray photoelectron spectroscopy - exported CSV * Raman spectroscopy - exported CSV * Linear Sweep Voltammetry - exported CSV * Impedance spectroscopy - exported CSV * Tafel slope - exported CSV * Galvanostatic polarization curves for MEAs - exported CSV * High frequency response as function of the current - exported CSV * Specific capacity vs cycle number - exported CSV ______Date formats______ * YYYY-MM-DD * HH-MM-SS 24hr formate ______Units and abbreviations______ * EDS -> Energy dispersive spectroscopy * XPS -> X-ray photoelectron spectroscopy * CV -> Cyclic voltammetry * Linear Sweep Voltammetry -> LSV * All EDS spectra are in energy (KeV) vs counts per second (-) * All Chronoamperometric curves are in time (h) vs current density (mA cm-2) * All XPS data are in Binding Energy (eV) vs counts (-) * All raman spectra are in Raman shift (cm-1) vs counts (-) * All CV measurements are in Voltage (V vs reversible hydrogen electrode) vs current density (mA cm-2) * All Galvanostatic polarization curves for MEAs are in current density (A cm-2) vs potential (V) * Impedance measurements are in Z' (Ω) vs -Z'' (Ω) * Impedance measurements for MEAs are in Zrel (Ohm) vs Zim (Ohm) * Tafel slope are in log (current density (mA cm-2) vs overpotential Voltage (V vs reversible hydrogen electrode) * High frequency response as function of the current measurements in the potential window of 1.2-2.1 V are in current density (A cm-2) vs HFR (mOhm) ------------------------------------------------------------------------------------------------ ______List of files______ * Cycling voltametry VZ2_019_021_VSCHT_S_0001_v1.csv -> CV for Co-WSe2_100mV.csv VZ2_019_021_VSCHT_S_0002_v1.csv -> CV for Co-WSe2_200mV.csv VZ2_019_021_VSCHT_S_0003_v1.csv -> CV for Co-WSe2_300mV.csv VZ2_019_021_VSCHT_S_0004_v1.csv -> CV for Co-WSe2_400mV.csv VZ2_019_021_VSCHT_S_0005_v1.csv -> CV for Co-WSe2_500mV.csv VZ2_019_021_VSCHT_S_0006_v1.csv -> CV for Co-WSe2_50mV.csv VZ2_019_021_VSCHT_S_0007_v1.csv -> CV for Ni-WSe2_100mV.csv VZ2_019_021_VSCHT_S_0008_v1.csv -> CV for Ni-WSe2_200mV.csv VZ2_019_021_VSCHT_S_0009_v1.csv -> CV for Ni-WSe2_300mV.csv VZ2_019_021_VSCHT_S_0010_v1.csv -> CV for Ni-WSe2_400mV.csv VZ2_019_021_VSCHT_S_0011_v1.csv -> CV for Ni-WSe2_500mV.csv VZ2_019_021_VSCHT_S_0012_v1.csv -> CV for Ni-WSe2_50mV.csv VZ2_019_021_VSCHT_S_0013_v1.csv -> CV for WSe2_100mV.csv VZ2_019_021_VSCHT_S_0014_v1.csv -> CV for WSe2_200mV.csv VZ2_019_021_VSCHT_S_0015_v1.csv -> CV for WSe2_300mV.csv VZ2_019_021_VSCHT_S_0016_v1.csv -> CV for WSe2_400mV.csv VZ2_019_021_VSCHT_S_0017_v1.csv -> CV for WSe2_500mV.csv VZ2_019_021_VSCHT_S_0018_v1.csv -> CV for WSe2_50mV.csv VZ2_019_021_VSCHT_S_0019_v1.csv -> Scan rate dependence of the current densities for Co-WSe2csv.csv VZ2_019_021_VSCHT_S_0020_v1.csv -> Scan rate dependence of the current densities for Ni-WSe2csv.csv VZ2_019_021_VSCHT_S_0021_v1.csv -> Scan rate dependence of the current densities for WSe2csv.csv * Galvanostatic polarization curves for MEAs VZ2_019_021_VSCHT_D_0022_v1.csv -> Polarization curves for MEAs for Co-WSe2 after the stability test.csv VZ2_019_021_VSCHT_D_0023_v1.csv -> Polarization curves for MEAs for Co-WSe2 before the stability test.csv VZ2_019_021_VSCHT_D_0024_v1.csv -> Polarization curves for MEAs for IrO2-PtC before the stability test.csv VZ2_019_021_VSCHT_D_0025_v1.csv -> Polarization curves for MEAs for Ni-WSe2 after the stability test.csv VZ2_019_021_VSCHT_D_0026_v1.csv -> Polarization curves for MEAs for Ni-WSe2 before the stability test.csv VZ2_019_021_VSCHT_D_0027_v1.csv -> Polarization curves for MEAs for WSe2 after the stability test.csv VZ2_019_021_VSCHT_D_0028_v1.csv -> Polarization curves for MEAs for WSe2 before the stability test.csv * High frequency response as function of the current VZ2_019_021_VSCHT_D_0029_v1.csv -> High frequency response for Co-WSe2 after the stability test .csv VZ2_019_021_VSCHT_D_0030_v1.csv -> High frequency response for Co-WSe2 before the stability test .csv VZ2_019_021_VSCHT_D_0031_v1.csv -> High frequency response for Ni-WSe2 after the stability test .csv VZ2_019_021_VSCHT_D_0032_v1.csv -> High frequency response for Ni-WSe2 before the stability test .csv VZ2_019_021_VSCHT_D_0033_v1.csv -> High frequency response for WSe2 after the stability test .csv VZ2_019_021_VSCHT_D_0034_v1.csv -> High frequency response for WSe2 before the stability test .csv * Impedance VZ2_019_021_VSCHT_D_0035_v1.csv -> Nyquist plot for Co-WSe2.csv VZ2_019_021_VSCHT_D_0036_v1.csv -> Nyquist plot for Ni-WSe2.csv VZ2_019_021_VSCHT_D_0037_v1.csv -> Nyquist plot for PtC.csv VZ2_019_021_VSCHT_D_0038_v1.csv -> Nyquist plot for WSe2.csv VZ2_019_021_VSCHT_D_0039_v1.csv -> Nyquist plot for Co-WSe2.csv VZ2_019_021_VSCHT_D_0040_v1.csv -> Nyquist plot for Ni-WSe2.csv VZ2_019_021_VSCHT_D_0041_v1.csv -> Nyquist plot for RuO2.csv VZ2_019_021_VSCHT_D_0042_v1.csv -> Nyquist plot for WSe2.csv * Impedance measurements for MEAs VZ2_019_021_VSCHT_D_0043_v1.csv -> Nyquist plot for Co-WSe2 after the stability test.csv VZ2_019_021_VSCHT_D_0044_v1.csv -> Nyquist plot for Co-WSe2 before the stability test.csv VZ2_019_021_VSCHT_D_0045_v1.csv -> Nyquist plot for Ni-WSe2 after the stability test.csv VZ2_019_021_VSCHT_D_0046_v1.csv -> Nyquist plot for Ni-WSe2 before the stability test.csv VZ2_019_021_VSCHT_D_0047_v1.csv -> Nyquist plot for WSe2 after the stability test.csv VZ2_019_021_VSCHT_D_0048_v1.csv -> Nyquist plot for WSe2 before the stability test.csv * LSV VZ2_019_021_VSCHT_D_0049_v1.csv -> LSV for Co-WSe2 after 10000 cycles .csv VZ2_019_021_VSCHT_D_0050_v1.csv -> LSV for Co-WSe2.csv VZ2_019_021_VSCHT_D_0051_v1.csv -> LSV for Ni-WSe2 after 10000 cycles .csv VZ2_019_021_VSCHT_D_0052_v1.csv -> LSV for Ni-WSe2.csv VZ2_019_021_VSCHT_D_0053_v1.csv -> LSV for PtC.csv VZ2_019_021_VSCHT_D_0054_v1.csv -> LSV for WSe2.csv VZ2_019_021_VSCHT_D_0055_v1.csv -> LSV for Co-WSe2 after 10000 cycles.csv VZ2_019_021_VSCHT_D_0056_v1.csv -> LSV for Co-WSe2.csv VZ2_019_021_VSCHT_D_0057_v1.csv -> LSV for Ni-WSe2 after 10000 cycles.csv VZ2_019_021_VSCHT_D_0058_v1.csv -> LSV for Ni-WSe2.csv VZ2_019_021_VSCHT_D_0059_v1.csv -> LSV for RuO2.csv VZ2_019_021_VSCHT_D_0060_v1.csv -> LSV for WSe2.csv * Ohmic drop corrected polarization curves for the MEAs VZ2_019_021_VSCHT_S_0061_v1.csv -> Ir-corrected curves for WSe2 after the stability test .csv VZ2_019_021_VSCHT_S_0062_v1.csv -> Ir-Corrected curves for Co-WSe2 after the stability test .csv VZ2_019_021_VSCHT_S_0063_v1.csv -> Ir-corrected curves for Co-WSe2 before the stability test .csv VZ2_019_021_VSCHT_S_0064_v1.csv -> Ir-corrected curves for Ni-WSe2 after the stability test .csv VZ2_019_021_VSCHT_S_0065_v1.csv -> Ir-corrected curves for WSe2 before the stability test .csv VZ2_019_021_VSCHT_S_0066_v1.csv -> Ir-orrected curves for Ni-WSe2 before the stability test .csv * Raman VZ2_019_021_VSCHT_D_0067_v1.csv -> Raman spectrum for Co-WSe2.csv VZ2_019_021_VSCHT_D_0068_v1.csv -> Raman spectrum for Ni-WSe2.csv VZ2_019_021_VSCHT_D_0069_v1.csv -> Raman spectrum for WSe2.csv * Tafel slope VZ2_019_021_VSCHT_D_0070_v1.csv -> Tafel slope for Co-WSe2.csv VZ2_019_021_VSCHT_D_0071_v1.csv -> Tafel slope for Ni-WSe2.csv VZ2_019_021_VSCHT_D_0072_v1.csv -> Tafel slope for PtC.csv VZ2_019_021_VSCHT_D_0073_v1.csv -> Tafel slope for WSe2.csv VZ2_019_021_VSCHT_D_0074_v1.csv -> Tafel slope for Co-WSe2.csv VZ2_019_021_VSCHT_D_0075_v1.csv -> Tafel slope for Ni-WSe2.csv VZ2_019_021_VSCHT_D_0076_v1.csv -> Tafel slope for RuO2.csv VZ2_019_021_VSCHT_D_0077_v1.csv -> Tafel slope for WSe2.csv * XPS VZ2_019_021_VSCHT_S_0078_v1.csv -> Co 2p for Co-WSe2.csv VZ2_019_021_VSCHT_S_0079_v1.csv -> Ni 2p for Ni-WSe2.csv VZ2_019_021_VSCHT_D_0080_v1.csv -> Se 3d for Co-WSe2.csv VZ2_019_021_VSCHT_D_0081_v1.csv -> Se 3d for Ni-WSe2.csv VZ2_019_021_VSCHT_D_0082_v1.csv -> Se 3d for WSe2.csv VZ2_019_021_VSCHT_D_0083_v1.csv -> W 4f for Co-WSe2.csv VZ2_019_021_VSCHT_D_0084_v1.csv -> W 4f for Ni-WSe2.csv VZ2_019_021_VSCHT_D_0085_v1.csv -> W4f for WSe2.csv