#00579Visible Light Photodegradation of Azo Dyes Using Free Standing and spin coated Cu-Based Nanoparticles: Application in Solar Batteries

D. Advanced Catalytic Materials for (photo)electrochemical energy conversion V
P. Paredes 1,*, P. Rauwel 1, E. Rauwel 1, D. Wragg 2, L. Rapenne 3, I. GĂ©lard 3.
1Estonian University of Life Sciences - Tartu (Estonia), 2University of Oslo - Oslo (Norway), 3University Grenoble Alpes - Grenoble (France)

*Corresponding author(s).
Email: patricio.paredes@emu.ee (P.Paredes)
Abstract

In this work, Cu2O, Cu-Cu2O, Cu-Cu3N, Cu-Cu2O-Cu3N nanoparticle mixtures and pure Cu metal nanoparticles were synthesized via non-aqueous sol-gel method for visible-light photocatalytic degradation of azo dyes. The as-prepared nanoparticles were analysed through X-ray diffraction, transmission electron microscope, scanning electron microscopy, X-ray photoemission spectroscopy, cyclic voltammetry and UV-Vis spectroscopy. Furthermore, the nanoparticles were also deposited on a glass substrate by spin-coating method, to facilitate the recovery process after their use. The photocatalytic behaviour of the nanoparticles was evaluated on the photodegradation of neutral red, malachite green and methylene blue dyes under a solar simulator and direct sunlight exposure. The maximum photodegradation efficiencies under natural sunlight are 70% for neutral red (150 min), 84% for malachite green (300 min) and 89% for methylene blue (300 min) using Cu2O-Cu3N-Cu nanoparticle mixture. We demonstrate that the higher removal efficiency that is observed for malachite green and methylene blue is attributed to their cationic form. However, for neutral red, after photocatalysis the dye undergoes in a photoconversion from its cationic to neutral form, which inhibite the complete degradation of the dye. In addition, similar dye degradation efficiencies were obtained by using free-standing and spin-coated films photocatalyst. Nevertheless, the interest in using spin-coated nanoparticle films lies in their easy recovery, which solves a key problem for practical applications related to photocatalysts. On the other hand, the exploration of the photoelectrocatalytic properties of Cu metal nanoparticles and their hybrids Cu@CNTs nanocomposites were studied in a three-electrode device configuration containing methylene blue as an electrolyte for solar battery applications. It is proposed that redox properties of methylene blue may contribute to the increase in the anodic/cathodic current generation. From an environmental and energy aspect, the recycling of industrial wastewater to produce energy could be a viable solution.

Keywords: Cu-based nanoparticles, photocatalysis, electrophotocatalysis, azo dyes degradation.

References:

1.         Paredes et al., Nanomaterials 2022, 12, (13), 2218.

2.         Paredes et al. Nanomaterials 2023, 13, (8), 1311.