Broad spectrum photocatalytic system based on BiVO4 and NaYbF4:Tm3+ upconversion particles for environmental remediation under UV-vis-NIR illumination

• Autor(a) principal: Ullah, S. [UNESP]
• Data de Publicação: 2019
• Outros Autores: Ferreira-Neto, E. P. [UNESP], Hazra, C. [UNESP], Parveen, R., Rojas-Mantilla, H. D. [UNESP], Calegaro, M. L., Serge-Correales, Y. E. [UNESP], Rodrigues-Filho, U. P., Ribeiro, S. J.L. [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1016/j.apcatb.2018.09.091; http://hdl.handle.net/11449/186986
• topic: Bismuth vanadate; Heterojunction; Microwave-method; Upconversion; UV–vis-NIR photocatalysis

The development of photocatalysts responsive towards a broader region of the solar (UV-to-NIR) light is important for efficient harvesting of sunlight for photochemical and photoelectrical applications. In this study, two photocatalytic systems (BV/LEDs and BV/UCPs where UCPs stands for NaYbF4:Tm3+ upconversion particles) based on bismuth vanadate (BV) are introduced for photocatalytic degradation of both organic dyes (crystal violet, CV) and pharmaceuticals (sulfathiazole, STZ) under a variety of photoactivation modes including low-power (1.26 W) LEDs and near infrared (NIR) irradiation as well as natural sunlight. The BV/LEDs system makes use of the perfect match between the emission profile of commercial blue LEDs (460 ± 10 nm) and absorption profile of BV (Eg = 2.6 eV) to effectively photodegrade pollutants. The BV/UCPs system, on the other hand, exploits the NIR-to-UV/visible upconverted light from UCPs to allow photodegradation of pollutants under NIR illumination. Moreover, we present a detailed study of the experimental parameters to obtain BV particles with tailored morphology (spherical, rod-like, hyperbranched), crystalline phase (monoclinic, tetragonal or heterojunction biphasic BV) and band gap energy (2.4–2.9 eV). Depending on the phase composition, a synergetic effect in photoactivity is observed in samples containing around 68% monoclinic and 30% tetragonal BV which is ascribed to the formation of monoclinic/tetragonal heterojunction.