Fast and facile sonochemical synthesis of Mg- and Zn-doped PbS nanospheres: optical properties and photocatalytic activi
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Fast and facile sonochemical synthesis of Mg‑ and Zn‑doped PbS nanospheres: optical properties and photocatalytic activity N. F. Andrade Neto1 · O. B. M. Ramalho1 · H. Fantucci2 · R. M. Santos2 · M. R. D. Bomio1 · F. V. Motta1 Received: 6 April 2020 / Accepted: 8 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract In this work, Mg2+- and Zn2+-doped PbS nanopowders were synthesized simply and quickly by a sonochemical method. The nanopowders were characterized by X-ray diffraction, wavelength dispersive X-ray fluorescence, scanning electron microscopy, and ultraviolet–visible spectroscopy. The photocatalytic activity was estimated by methylene blue dye degradation. The sonochemical method produces crystalline PbS particles with cubic structure and free of secondary phases. The use of polyvinylpyrrolidone as a surfactant, and reaction medium at pH 13, results in the formation of nanospheres with diameter ranging from 31.4 to 114.5 nm. Doping favors the absorption of radiation in the visible region, and consequently, reduces the optical bandgap of the PbS. Photocatalytic assays show that magnesium and zinc codoping results in 80% reduction of methylene blue concentration after 180 min, while undoped PbS achieves only 42%. Tests with charge scavengers indicate that holes (h+) act as the main mechanism in the photocatalytic process.
1 Introduction Continued industrial development has led to increasing concern with wastewater treatment availability and effectiveness, wherein the removal or degradation of organic dyes has gained attention [1, 2]. Approximately 20% of the world’s pigment production is lost during dyeing, being released as part of textile wastewater, and thus requiring treatment to protect the environment and water supply [3]. Advanced oxidative processes (AOPs), especially those applying heterogeneous photocatalysis, are widely studied as green chemistry approaches, as they generate water, carbon dioxide gas and inorganic salts from the mineralization of organic compounds [4, 5]. Such technique consists of exposing a semiconductor material to appropriate radiation in order to Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10854-020-03975-7) contains supplementary material, which is available to authorized users. * N. F. Andrade Neto [email protected] 1
LSQM, Laboratory of Chemical Synthesis of Materials, Department of Materials Engineering, Federal University of Rio Grande do Norte, UFRN, P.O. Box 1524, Natal, RN, Brazil
School of Engineering, University of Guelph, Guelph, ON N1G 2W1, Canada
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excite the valence band (VB) electrons to the conduction band (CB), forming electron/hole pairs ( ecb/h+vb), which when in contact with an aqueous solution containing organic dye compounds generates reactive oxygen species (ROS) that have high oxidative capacity [6, 7]. Semiconductors have been studied for use in AOP due to their adaptable optical and electronic properties, whereby these properties can be r
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