Insight into Potassium Vanadates as Visible-Light-Driven Photocatalysts: Synthesis of V(IV)-Rich Nano/Microstructures for the Photodegradation of Methylene Blue

Małgorzata Nadolska; Mariusz Szkoda; Konrad Trzciński; Paweł Niedziałkowski; Jacek Ryl; Aleksandra Mielewczyk-Gryń; Karolina Górnicka; Marta Prześniak-Welenc

doi:10.1021/acs.inorgchem.2c00136

Insight into Potassium Vanadates as Visible-Light-Driven Photocatalysts: Synthesis of V(IV)-Rich Nano/Microstructures for the Photodegradation of Methylene Blue

Inorg Chem. 2022 Jun 27;61(25):9433-9444. doi: 10.1021/acs.inorgchem.2c00136. Epub 2022 Jun 10.

Authors

Małgorzata Nadolska¹, Mariusz Szkoda², Konrad Trzciński², Paweł Niedziałkowski³, Jacek Ryl¹, Aleksandra Mielewczyk-Gryń¹, Karolina Górnicka¹, Marta Prześniak-Welenc¹

Affiliations

¹ Faculty of Applied Physics and Mathematics, Institute of Nanotechnology and Materials Engineering, Gdansk University of Technology, Narutowicza 11/12, Gdansk 80-233, Poland.
² Faculty of Chemistry, Gdansk University of Technology, Narutowicza11/12, Gdansk 80-233, Poland.
³ Faculty of Chemistry, University of Gdansk, Wita Stwosza 63, Gdansk 80-308, Poland.

Abstract

Photocatalysis is regarded as a promising tool for wastewater remediation. In recent years, many studies have focused on investigating novel photocatalysts driven by visible light. In this study, K₂V₆O₁₆·nH₂O nanobelts and KV₃O₈ microplatelets were synthesized and investigated as photocatalysts. Samples were obtained via the facile method based on liquid-phase exfoliation with ion exchange. By changing the synthesis temperature (20-80 °C), different compositions, morphologies, and V⁴⁺/V⁵⁺ ratios were obtained and investigated as photocatalysts for organic dye degradation. Potassium vanadates' structural, morphological, and optical properties were characterized using X-ray diffraction(XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Physical Property Measurement System (PPMS), thermogravimetric analysis (TGA) with mass spectrometry (MS), N₂ adsorption, scanning electron microscopy (SEM), photoluminescence (PL), and UV-vis diffuse reflectance spectroscopy (DRS). Synthesized K₂V₆O₁₆·nH₂O and KV₃O₈ showed an efficient absorption in the visible wavelength region with a narrow band gap energy of 1.80 and 1.91 eV, respectively. Their photocatalytic activity was evaluated by the degradation of methylene blue (MB) under simulated solar light illumination. The KV₃O₈ microplatelets exhibited the greatest photocatalytic activity, resulting in more than 90% degradation of the dye within the first 30 min. It is suggested that the observed excellent photocatalytic performance is attributed to the high content of V⁴⁺ species. Furthermore, the influence of active species was investigated, and the mechanism responsible for the photodegradation of the MB dye was discussed for the first time for potassium vanadates.