Ceria/Gold Nanoparticles in Situ Synthesized on Polymeric Membranes with Enhanced Photocatalytic and Radical Scavenging Activity

Abstract

This study reports a novel two-step approach to fabricate poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/cerium oxide (CeO 2 ) nanocomposite fibrous membranes. The fabrication method is based on the combination of the electrospinning of a polymer/cerium salt solution and the subsequent in situ thermally activated conversion of the salt in CeO 2 nanoparticles, directly in the polymeric fibers. This procedure leads to a homogeneous filler dispersion not only in the bulk of the polymeric fibers but also on their surface, thus conferring to the system remarkable properties, such as radical scavenging and photocatalytic activity. These properties are further improved by the decoration of the CeO 2 with gold nanoparticles, formed upon the dipping of the solid PVDF-HFP/CeO 2 fibers in a gold precursor solution and their subsequent thermal treatment, thanks to the modification of the Ce 3+ /Ce 4+ ratio and the absorption spectrum shifted toward visible wavelengths. Specifically, the presence of Au on the surface of the PVDF-HFP/CeO 2 fibrous membranes dramatically enhances the radical scavenging activity, which reaches up to 90% of scavenged radicals in 24 h. In addition, the photocatalytic degradation activity is remarkably improved, making possible to photodegrade organic dyes under visible light. Such performances, in combination with the straightforward fabrication method, the high surface area, the light weight, and flexibility, offered by the polymeric fibers make the presented system a valuable alternative to the existing ceria-based systems, e.g., ceramic supported, opening up an innovative route to fabricate multifunctional membranes for water purification or bioapplications due to the CeO 2 antioxidant properties.

Self‐Assembled PMMA Porous Membranes Decorated with In Situ Synthesized ZnO Nanoparticles with UV‐Tunable Wettability

“…Recently, this technique in combination with electrospinning was employed to fabricate fibrous multifunctional membranes. [ 12,13 ] Such method is based on the incorporation, in the polymeric matrix, of suitable NPs precursor that can be then converted in the desired NPs by thermal [ 12,13 ] or photoactivation. [ 14 ]…”

Au/ZnO Hybrid Nanostructures on Electrospun Polymeric Mats for Improved Photocatalytic Degradation of Organic Pollutants

“…To avoid these post-treatment steps, the photo-catalyst powders can be immobilized on suitable solid supports [9,10]. To this aim, polymeric supports have been recently introduced due to their low weight, flexibility, and easy conversion in different morphologies [11][12][13][14][15][16]. Among them, fibrous polymeric mats have high surface area, which allows an enhanced interaction with the polluted water, and their preparation process is relatively simple and easily scaled up [9,17].…”

“…For the fabrication of the functional semiconductor based polymeric materials, an innovative approach has been recently proposed, dealing with the direct synthesis of NPs inside different polymeric matrices through a solid-state thermally, chemically, or photo-induced reaction [13,[17][18][19]. Compared to traditional mixing processes, this approach offers the advantageous formation of NPs homogeneously distributed not only in the whole volume of the polymer matrix, but also exposed on its surface.…”

“…Compared to traditional mixing processes, this approach offers the advantageous formation of NPs homogeneously distributed not only in the whole volume of the polymer matrix, but also exposed on its surface. Furthermore, limitations such as the complex rheology of polymer/NP solutions, which can limit their electrospin-ability and therefore the formation of fibrous nanocomposites, can be avoided [13,17]. Among the diverse types of nanocomposites developed so far following this approach [13,17,20], the ZnO-based mats is a promising system for the water remediation through the photocatalytic approach.…”

“…Furthermore, limitations such as the complex rheology of polymer/NP solutions, which can limit their electrospin-ability and therefore the formation of fibrous nanocomposites, can be avoided [13,17]. Among the diverse types of nanocomposites developed so far following this approach [13,17,20], the ZnO-based mats is a promising system for the water remediation through the photocatalytic approach. In fact, ZnO is of great interest not only because it is environmental friendly, non-toxic, of low-cost, and abundant, but also because of its optoelectronic properties [9,[21][22][23][24].…”