DOI: 10.5281/zenodo.18659832
title: Characterization of Nanostructures containing WO3, MoO3, TiO2 and ZnO for Photoelectrocatalytic Degradation of the Pesticide Imazalil (DATASET)

description: The dataset contains the data that have been used to synthesize and characterize different types of nanostructures (WO3, WO3-Mo, TiO2, and TiO2-ZnO) for a comparison of hybrid and purenanostructures to use them as a photoanodes for photoelectrocatalytic degradation of emerging contaminants. 

Description of methods used for collection/generation of data: 

- Raman and XRD tests

The crystallinity of the nanostructure was analyzed by a Raman confocal laser spectroscopy (Witec alpha 300R,Ulm, Germany) with a neon laser of 488 nm at 420 microW and also by X-ray diffraction (XRD)using a D8AVANCE diffractometer (Bruker, MA, USA) equipped with a monochromatic Cu Kalfa1 source.

- Photoelectrochemical Properties: PEIS, Mott-Schottky, and Water Splitting tests

A potentiostat (Autolab PGSTAT302N, Metrohm, Herisau, Switzerland) and a solarsimulator (500 W xenon lamp) were used to study the photoelectrochemical properties ofthe samples. Photoelectrochemical impedance spectroscopy (PEIS) tests were performed to analyze theelectrochemical and photoelectrochemical behavior of each synthesized sample. For theWO3 samples, the tests were carried out applying simulated sunlight with the simulatormentioned before and a potential of 1 VAg/AgCl in a frequency range of 100 kHz to 10 mHzwith a signal amplitude of 10 mV. The electrolyte used was 0.1 M H2SO4. On the other hand,for the TiO2 nanostructures, the applied potential was 0.6 VAg/AgCl and the electrolytewas 0.1 M NaOH, the rest of the conditions being the same. Mott–Schottky measurements were also applied.For the WO3 nanostructures, from 1 to 0.2 VAg/AgCl at a frequency of 5 kHz, and for the TiO2 nanostructuresfrom 0.8 to -0.9 VAg/AgCl at a frequency of 10 kHz, for both cases at a scan rate of 50 mV·s−1 and a frequency of 5 kHz with an amplitude signal of 10 mV. For Water Splitting tests, a potential sweep with a scan speed of 2 mV·s-1 was carried out, applying dark (30 s) and light (10 s) cycles. 

- Photoelectrocatalytic Degradation

The PEC degradation was carried out starting from a 10 ppm solution of Imazalil underlighting conditions (AM 1.5) at a potential of 0.6 VAg/AgCl for 24 h. The electrodes usedwere TiO2/ZnO hybrid nanostructures as photoanodes, an Ag/AgCl (3 M KCl) referenceelectrode, and a platinum wire as a counter electrode. The electrolyte of the Imazalil wasoptimized. The electrolyte of the first degradation was 0.1 M NaOH (pH = 13), and theoptimized electrolyte was 0.1 M Na2SO4 (pH = 6.2).

The degradation course was monitored by ultra high performance liquid chromatographyand mass spectrometry (UHPLC-MS-QTOF). The equipment used was an Agilent1290 Infinity equipped with a C-18 analytical column (Agilent ZORBAX Eclipse Plus, SantaClara, CA, USA) of 50 mm x 2.1 mm with a particle size of 1.8 microm. The mobile phases werewater (A) and acetonitrile (B), both acidified with 0.1% (v/v) acetic acid. The experimentalconditions of the equipment were the following: injection volume of 0.2 microL, flow rate of1 mL·min-1, and column temperature of 45 ºC. Furthermore, the conditions for the massspectrometer were: positive ionization, capillary voltage 4000 V, nebulizer pressure 40 psi,gas temperature 325 ºC, skimmer voltage 65 V, octopolar rf 250 V, and voltage fragmentor190 V.