Degradation of Diazinon based on photoelectrocatalytic technique using WO3 nanostructures [Dataset]

In this work, a resistant and toxic pesticide called diazinon was degraded through the photoelectrocatalysis (PEC) technique using tungsten oxide (WO3) nanostructures, applying an external bias of 1VAg/AgCl and simulated solar illumination. For this, WO3 nanostructures have been synthesized using electrochemical anodization in 0.05 M hydrogen peroxide and 1.5 M of different acidic electrolytes: H2SO4, CH4O3S or HNO3. Morphology, composition and crystallinity of the samples were evaluated through Field Emission Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM) and Raman Spectroscopy. Then, the photoelectrochemical properties of the samples were analyzed by Photo-Electrochemical Impedance Spectroscopy (PEIS). The conclusion obtained with these studies was that the nanostructures obtained in the CH4O3S-H2O2 electrolyte presented better photoelectrochemical behavior than the others. The degradation process was checked by UV-Visible, and through Ultra High-Performanc liquid Chromatography and Mass Spectrometry (UHPLC-Q-TOF/MS) the courses of the experiments have been controlled and five possible degradation intermediates have been identified. Finally, after 24 h of experiment, 90% degradation efficiency has been achieved, since it has been possible to decrease from 20 ppm to 2 ppm. Description of methods used for collection/generation of data: -Synthesis of WO3 nanostructures WO3 nanostructures were synthetized by electrochemical anodization using three different electrolytes, with H2O2 0.05 M in all of them.The first one was sulfuric acid (H2SO4) 1.5 M. The second one was nitric acid (HNO3) 1.5 M, and finally, the third one was methanesulfonic acid(CH4O3S) 1.5 M.Anodization was executed at a constant potential of 20 V using an Elektro-Automatik power source for 4 h, with W rod as the anode and a platinum mesh as the cathode, and the electrolyte temperature was 50 ◦C. The velocity at which the working electrode (tungsten rod) was rotating was at 375 rpm by using a Rotating Disk Electrode (RDE). - Electrochemical charaterization: Photoelectrochemical properties were studied using a threeelectrode assembly with a platinum mesh as counter electrode and a Ag/AgCl 3 M KCl reference electrode. The samples were electrically connected with a potentiostat (Autolab PGSTAT302N) exposing 0.5 cm2of active surface. The samples were submerged in 0.1 M H2SO4 solution.Photoelectrochemical impedance spectroscopy (PEIS) and Mott–Schottky tests were executed under illuminated conditions. PEIS measurements were taken at a potencial of 1 V (10 mV of amplitude) and scanning frequency from 10 KHz down to 10 mHz. Mott–Schottky type measurements were carried out at a frequency of 5 kHz using an amplitude signal of 10 mV and scanning the potential from a value of 0.5 V in the negative direction at a rate of 50 mV/s. - Photoelectrocatalytic degradation: The problem solution was studied by registering variations of the absorption spectra in the UV–vis spectra of diazinon using an UV–vis spectrophotometer (Unicam UV/Vis spectrometer UV4) every 30 min and after the measuring the aliquots were returned inside the reactor.