WO3 nanostrutures for Photoelectrocatalytic Applications (Dataset)

An electrochemical and photoelectrochemical characterization of WO3 nanostructures has been performed by means of Electrochemical Impedance Spectroscopy and Mott–Schottky measurements, as well as using cyclic voltammetry and Photocurrent density curves. Description of methods used for collection/generation of data: - Synthesis of Nanostructures The anodization technique was used for the formation of nanostructureson the metal surface. Tungsten (99.95%, 0.125 mm thick)sheets were cut in a circular shape of 1.3 cm2 and then ultrasonicallywashed with acetone, ethanol, and deionized water for2 min. An electrolyte of 1.5 M methanesulfonic, 95% (v/v) water,and 5% (v/v) [EMIM][BF4] was used. During anodization, 20 V wereapplied between tungsten (anode) and platinum (cathode), submergingboth in the electrolyte for 4 h at 50 °C. The hydrodynamicconditions were modified between 0, 200, 400, and 600 rpm. After anodization, the samples were washed in deionizedwater and then calcined at 600 °C for 4 h in air in order to obtainordered crystalline structures. - Electrochemical Characterization Electrochemical characterization was conducted in a three-electrodecell with the anodized tungsten film as the anode, platinum as thecathode, and Ag/AgCl (3 M KCl) as the reference electrode, and anelectrolyte of 0.1 M H2SO4 solution was employed for all the essays.To analyze the electrochemical properties of samples, electrochemicalimpedance spectroscopy (EIS) tests were performed at 1VAg/AgCl scanning frequencies from 100 kHz to 0.01 Hz. The procedure involved performingcyclic voltammetry within a potential range that excludesfaradaic processes, ensuring that only capacitive charging was measured.The potential was cycled from OCP ± 0.1 V (based on testscarried out in a wide range of potentials from the OCP as shownin Figure S3) for three cycles at scan rates of 0.01, 0.02, 0.05, 0.10,and 0.20 V s−1. Moreover, to determine the semiconductor characterof the samples and to calculate the number of charge carriers,Mott–Schottky (MS) plots were obtained at a frequency of 5000 Hz,scanning the potential from 0.0 to 1.0 VAg/AgCl (WO3). - Photoelectrochemical H2 Production The photoelectrochemical analysis was carried out using a solarsimulator equipped with a 300 W Xe lamp and an AM 1.5G filter.The evaluation of the hydrogen production from the water splittingusing the WO3 nanostructures was carried out with the sameconfiguration three-electrode cell and an electrolyte of 0.1 M H2SO4solution. Thus, the samples were subjected to light/dark conditions(16 s light, 4 s dark), applying a potential from 0 to 1.0 VAg/AgCl at 100mW cm−2.