This readme file was generated on [november 2023] by [José García Antón (Principal Investigator)] ___________________ GENERAL INFORMATION ___________________ Title of Dataset: Characterization of WO3 Nanostructures used in the degradation of Methylparaben The data were use to study the degradation of Methylparaben using WO3 Nanostructures and the influence of the annealing conditions and complexing agent Author/Principal Investigator Information Name: José García Antón ORCID: https://orcid.org/0000-0002-0289-1324 Institution: Universitat Politècnica de València Address: Camino de Vera s/n Email: jgarciaa@iqn.upv.es Author/Associate or Co-investigator Information Name: Mireia Cifre Herrando ORCID:https://orcid.org/0000-0002-8800-3585 Institution: Universitat Politècnica de València Address: Camino de Vera s/n Email: mcifher@upvnet.upv.es Author/Associate or Co-investigator Information Name: Gemma Roselló Márquez ORCID:https://orcid.org/0000-0002-3116-1312 Institution: Universitat Politècnica de València Address: Camino de Vera s/n Email: gemromar@etsii.upv.es Author/Associate or Co-investigator Information Name: Dionisio M. García García ORCID:https://orcid.org/0000-0001-8951-4558 Institution: Universitat Politècnica de València Address: Camino de Vera s/n Email: diogarg1@iqn.upv.es Date of data collection: 2022 Geographic location of data collection: Valencia, Spain Keywords: photoelectrocatalysis; WO3 nanostructures; endocrine disruptors Information about funding sources that supported the collection of the data: Ministerio de Ciencia e Innovación (Project code: PID2019- 105844RB-I00/AEI/10.13039/501100011033). Project co-funded by FEDER operational programme 2014-2020 of Comunitat Valenciana (IDIFEDER/18/044) for the financial funding __________________________ SHARING/ACCESS INFORMATION __________________________ Licenses/restrictions placed on the data: COPYRIGHT Links to publications that cite or use the data: https://doi.org/10.3390/nano12234286 Nanomaterials 12 (2022) 4286 (OPEN ACCESS) ______________________ DATA & FILE OVERVIEW ______________________ File List: - Raman, Stability and WS tests: The crystallinity of the samples was analyzed using a Raman laser microscope. Stability tests at 1 VAg/AgCl for 1 h were carried out to check their photostability to photocorrosion. Water-splitting (WS) tests were performed to study the photoelectrochemical properties of the nanostructures. - Mott–Schottky tests: Mott–Schottky tests at different conditions were performed to study the photoelectrochemical properties of the nanostructures. - PEIS tests_Bode: Bode diagrams obtained from Photoelectrochemical Impedance Spectroscopy test at different conditions were performed to study the photoelectrochemical properties of the nanostructures. - PEIS tests_Nyquist: Nyquist diagrams obtained from Photoelectrochemical Impedance Spectroscopy test at different conditions were performed to study the photoelectrochemical properties of the nanostructures. - XPS_tests: Samples were characterized by X-ray photoelectron spectroscopy (XPS) to obtain information about the electronic states of the nucleus and about the chemical status of WO3 nanostructures. - XRD tests: Samples were characterized by X-ray diffraction (XRD) to obtain more detail about the their crystalline structure. - HPLC degradation tests: The degradation process was followed by means of ultra high-performance liquid chromatography and mass spectrometry (UHPLC-MS-Q-TOF). METHODOLOGICAL INFORMATION Materials: Tungsten (W) bars of 99.5% purity with a diameter of 8 mm were used as working electrodes. Methanosulfonic acid (CH4O3S), hydrogen peroxide (H2O2), citric acid (C6H8O7) and sulphuric acid (H2SO4) were purchased from Sigma Aldrich. WO3 Nanostructures Fabrication: The procedure followed to obtain the WO3 nanostructures was carried out by W electrochemical anodization under hydrodynamic conditions. First, before anodization, the W rod was conditioned. The W bar was polished using silicon carbide (SiC) papers of different grades (220, 500 and 4000) in order to obtain a mirror-like surface. Thereafter, the surface was washed with distilled water, sonicated in ethanol for 2 min and dried with air. Lastly, the sample was Teflon-coated to expose only a circular area of 0.5 cm2 to the electrolyte. For anodization, the polished W was used as a working electrode and a platinum foil as the counter electrode. During anodization, 20 V were applied for 4 h. The electrolyte was composed of 1.5 M methanosulfonic acid plus the complexing agent at 50 ºC. The tungsten bar was assembled on a rotating disk electrode, and it was rotated continuously at a speed of 375 rpm. Two different complexing agents were used in order to find the optimal WO3 nanostructure: 0.05 M H2O2 and 0.1 M citric acid. The concentration chosen for each electrolyte was proved to be optimal in previous works. After anodization, WO3 nanostructures were annealed at different temperatures (400 ºC, 500 ºC and 600 ºC) in a flowing air atmosphere for 4 h to examine the effect of the annealing temperature on the nanostructure. Nanostructures Characterization: The crystallinity of the samples was analyzed using a confocal Raman laser microscope (Witec alpha300 R confocal Raman microscope, Ulm, Germany) with a neon laser of 488 nm with a power of 420 microW. To further study, the best obtained samples were also characterized by X-ray diffraction (XRD) using a Bruker D8AVANCE (Bruker, Billerica, MA, USA) diffractometer with a Cu radiation operating at 40 kV from 5 ºC to 80 ºC and X-ray photoelectron spectroscopy (XPS, K-ALPHA Thermo Scientific,Waltham, MA, USA). All XPS spectra were captured by Al-K monochromatized radiation (1486.6 eV) at 3 mA  12 kV. The whole energy band was measured with scan pass energies of 200 eV and the specific elements at 50 eV. The experimental backgrounds were approximated by a smart background function and surface elemental composition was calculated from background subtracted peak areas. XRD permitted to obtain more detail about the crystalline structure of the samples, and XPS provided information about the electronic states of the nucleus and about the chemical status of WO3 nanostructures. Photoelectrochemical measurements under illuminated conditions were carried out using an Autolab PGSTAT302N potentiostat (Metrohm, Herisau, Switzerland) and a solar simulator (AM 1.5 conditions at 100 mW·cm2). A three-electrode cell configuration was used, consisting of an Ag/AgCl (3 M KCl) reference electrode, a platinum tip as a counter electrode, and the WO3 nanostructures as a working electrode. The electrolyte used for all the photoelectrochemical measurements was 0.1 M H2SO4, to ensure the photostability of the electrode. First, stability tests at 1 VAg/AgCl for 1 h were carried out for all the samples to check their photostability to photocorrosion. After that, photoelectrochemical impedance spectroscopy (PEIS) and Mott–Schottky tests were performed. On one hand, PEIS measurements were carried out, applying 1 VAg/AgCl in the frequency range varied from 100 kHz to 10 mHz with a 10 mV of amplitude. On the other hand, Mott–Schottky measurements were performed from 1 to 0.2 VAg/AgCl at a scan rate of 50 mV·s-1 and a frequency of 5 kHz with an amplitude signal of 10 mV. For stability, PEIS and Mott–Schottky tests of the area of the WO3 nanostructure exposed to the electrolyte was 0.5 cm2. After that, water-splitting tests were performed with the best samples, and photocurrent densities against potential curves were obtained. A potential sweep was scanned from 0.2 VAg/AgCl to 1.0 VAg/AgC at a scan rate of 2 mV·s-1 by pulsed light irradiation, 60 s light off and 20 s light on. PEC Degradation: PEC degradation tests were performed in a photoelectrochemical quartz reactor of 14 mL in volume composed of a three-electrode electrochemical cell with the same configuration as the cell used for photoelectrohemical measurements (area of the anode = 0.5 cm2). A potentiostat provided 1V Ag/AgCl bias potential and a 1000WXenon lamp was used as a light source with an intensity of 100 mW/cm2. The distance from the lamp to the photoanode was 30 cm. The target solution to degrade was 10 ppm MP with 0.1M H2SO4 to assure acidic conditions and stability of the nanostructure. The PEC degradation was performed at room temperature, and the electrolyte was magnetically stirred. Samples were taken every hour during 24 h. The degradation process was followed by means of ultra high-performance liquid chromatography and mass spectrometry (UHPLC-MS-Q-TOF). The equipment used was an Agilent 1290 Infinity UHPLC equipment fitted with a C-18 analytical column (Agilent ZORBAX Eclipse Plus C18, 50 mm  2.1 mm, 1.8 m particle size). The temperature of the column was 30 ºC, the flow rate used was 0.8 mL/min, and the injection volume was 2 microL. Mobile phases consisted of (A) water + 0.01% Acetic Acid (v/v) and (B) methanol. The analysis started with 20% mobile phase B. Then, the solvent B increased linearly to 90% in 25 min, was kept at 90% for 1 min, and the initial condition was restored in 0.5 min. The re-equilibration time was 1.5 min. The total run time was less than thirty minutes. The UHPLC system was coupled to a time-of flight mass spectrometer (MS-Q-TOF) fitted with an electrospray interface operated in negative ionization mode. The MS spectra were registered from 70 to 1200 m/z. The parameters of the MS-Q-TOF were the following: capillary voltage 4000 V; nebulizer pressure 45 psi; drying gas flow rate 11 L/min; gas temperature 355 ºC; skimmer voltage 65 V; octopole rf 250 V; fragmentor voltage 90 V. Finally, data acquisition was performed by Agilent MassHunter Qualitative Analysis 10.0 Software.