Electrospun, flexible and reusable nanofiber mat of graphitic carbon nitride: Photocatalytic reduction of hexavalent chromium

Saha, Dipendu; Hoinkis, Tyler J.; Bramer, Scott E. Van

doi:10.1016/j.jcis.2020.04.090

Cited by 27 publications

(10 citation statements)

References 51 publications

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“…The FTIR spectra of pristine PVDF powder and activated PVDF powder are illustrated in Figure d. The wavenumbers of pristine PVDF powder were assigned as follows: 1401.39 (scissoring of CH 2 groups), 1278.10 (CH 2 rocking), 1183.26 (CH 2 /CH 3 deformation), 1069.46 (CF 2 symmetric stretching), and 841.84 cm –1 (rocking and asymmetric stretching of CH 2 /CF 2 ). , In comparison to pristine PVDF powder, the enhanced peak at 1676.42 cm –1 is attributed to the CC stretching vibration of the activated PVDF powder, which proved that the active double bonds were formed during the activation process with carbonate buffer.…”

Section: Results and Discussionmentioning

confidence: 99%

Multicomponent Composite Membrane with Three-Phase Interface Heterostructure as Photocatalyst for Organic Dye Removal

et al. 2022

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A multicomponent composite membrane (P-S-T/C) with three-phase interface heterostructure is ingeniously designed. A polydopamine (PDA)-modified conductive carbon fiber cloth (C FC ) is used as the substrate. Activated poly(vinylidene fluoride) (PVDF) with titanium dioxide (TiO 2 ) and a silicon dioxide (SiO 2 ) aerogel are electrospun as the top layer. The three-phase interface heterostructure was formed by TiO 2 , conductive C FC , and the SiO 2 aerogel. Its photocatalytic performance is validated by photodegradation of organic dyes in a low-oxygen (O 2 ) water environment. On combining with the capillary condensation of a bilayer structure, P-S-T/C exhibits excellent removal capability for anionic and cationic dyes. Moreover, P-S-T/C exhibits excellent stability and recyclability under simulated sunlight. The mechanism study indicates that the separated photogenerated carriers diffuse to the composite membrane surface rapidly on the three-phase interface of P-S-T/C. The abundant O 2 adsorbed on the porous SiO 2 aerogel surface acts as an electron (e – )-trapping agent, which can also decrease the work function of the composite materials. Superoxide radicals ( • O 2 – ) play a dominant role in the reaction of photodegradation supported by a free radical-trapping experiment. This work paves a way to design a membrane with photocatalytic performance by constructing the interface heterostructure.

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Section: Results and Discussionmentioning

confidence: 99%

Multicomponent Composite Membrane with Three-Phase Interface Heterostructure as Photocatalyst for Organic Dye Removal

et al. 2022

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“…In this reaction, the role of FA is to separate the (e − −h + ) pair through its wellknown h + scavenging properties. 8 To confirm the role of FA, we also conducted control experiments with or without FA using hybrid 1 as the catalyst. The absence of FA in the reaction media caused a significant reduction in the rateconstant value from 0.048 to 0.022 min −1 , which confirms the role of FA in the observed photocatalysis.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Photocatalytic reduction of Cr(VI) to Cr(III) is a preferred approach for the removal of Cr(VI) based on several economic and environmental considerations. Recent studies have shown that several semiconducting materials including graphitic carbon nitride (g-C 3 N 4 ), , bismuth oxyhalide (BiOX), chalcogenides, and metal oxides can function as efficient photocatalysts for the reduction of Cr(VI) into Cr(III).…”

Section: Introductionmentioning

confidence: 99%

Keggin Cluster Modulated Photocatalytic Activity of Aryl Sulfonium Polyoxometalate Hybrids toward Dichromate Reduction

2022

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Dichromate (Cr2O7 2–) ion having chromium in its +6 oxidation state is a carcinogen and a potential threat to humans and aquatic life. The photocatalytic reduction of toxic Cr(VI) species into less toxic Cr(III) is an important target in heterogeneous catalysis. In this work, the catalytic activities of a series of Keggin cluster-based aryl sulfonium polyoxometalate hybrids, (FPDS)3[PMo12O40] (1), (FPDS)3[PW12O40] (2), (FPDS)4[SiMo12O40] (3), and (FPDS)4[SiW12O40] (4), toward the photocatalytic reduction of Cr(VI) have been analyzed and compared. Here, we used the aryl sulfonium counterions to modulate the POM cluster’s solubility in water and stabilize the photogenerated e––h+ pair on the cluster. All of the hybrids 1–4 catalyzed the reduction of Cr(VI) to Cr(III) under ultraviolet (UV) irradiation, and their photocatalytic efficiencies followed the order hybrid 1 > hybrid 3 > hybrid 2 > hybrid 4, with the rate-constant values of 0.048, 0.0056, 0.0035, and 0.0028 min–1, respectively. Hybrid 1 with [PMo12O40]3– Keggin cluster exhibited the best photocatalytic activity in the series yielding a 99% reduction in 120 min. The reasons behind the best photocatalytic activity of hybrid 1 are identified as its low band gap, less charge recombination, and fast photoresponse. The electron-trapping analyses performed using AgNO3 revealed electrons as the main reactive species responsible for the photocatalytic reduction of Cr(VI). A plausible photocatalytic mechanism has also been proposed based on electron-trapping experiments. The present study shows that aryl sulfonium Keggin hybrids can function as efficient photocatalysts for Cr(VI) reduction, and their catalytic efficiency varies with the nature of the Keggin cluster.

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“…Hydrogel nanofibers have unique properties that make them promising candidates to support the production of nanoalloys. Firstly, nanofibers have appropriate structures for metal ion loading such as a small aperture with diameters ranging from several micrometers to less than 100 nm, a characteristic three-dimensional structure, and a high surface area–volume ratio. , The flexibility of the nanofiber substrate allows for folding and rolling with no loss in the structural integrity and for ease of fitting into containers of varying dimensions and shapes . In addition, the high surface area–volume ratio of hydrogel nanofibers corresponds to high water content, high gel strength, and swelling. ,, Thus, hydrogel nanofibers have been used as potential nanoreactors to contain aqueous reactions .…”

Section: Introductionmentioning

confidence: 99%

“…44,45 The flexibility of the nanofiber substrate allows for folding and rolling with no loss in the structural integrity and for ease of fitting into containers of varying dimensions and shapes. 46 In addition, the high surface area−volume ratio of hydrogel nanofibers corresponds to high water content, high gel strength, and swelling. 37,38,47 Thus, hydrogel nanofibers have been used as potential nanoreactors to contain aqueous reactions.…”

Section: ■ Introductionmentioning

confidence: 99%

Cu–Ag Alloy Nanoparticles in Hydrogel Nanofibers for the Catalytic Reduction of Organic Compounds

Sip

Fox

Shultz

et al. 2021

ACS Appl. Nano Mater.

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Nanoalloys or alloy nanoparticles containing multiple metals are of great interest because the combination of multiple metals in close proximity can grant enhanced properties including stability, activity, and selectivity arising from synergism that cannot be accessed by the combination of individual metals. In this study, we have produced nanoalloys in stable flexible electrospun hydrogel nanofibers composed of poly(acrylic acid) and poly(allylamine hydrochloride). The hydrogel fibers were loaded with metal ions such as copper and silver through an immersion in metal salt solutions followed by a chemical reduction to form the metal nanoparticles. The hydrogel matrix allowed for the absorption of metal ions into the fibers and provided a viscous environment to promote the formation of alloy particles in the small diameter range (<25 nm). The proposed fabrication process is advantageous in terms of simplicity, controllability, and versatility. The reductions of 4-nitrophenol and methylene blue were performed to test and compare the catalytic activity of monometallic nanoparticles and copper−silver bimetallic nanoparticles. The copper−silver bimetallic nanoparticles demonstrated preferred selectivity for the reduction of 4-nitrophenol and higher catalytic activity for the reduction of methylene blue. Overall, we have developed promising stable flexible nanocomposites for catalytic reduction of organic redox compounds, and other catalytic nanoalloy systems could be further studied by modification of the procedure.

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Electrospun, flexible and reusable nanofiber mat of graphitic carbon nitride: Photocatalytic reduction of hexavalent chromium

Cited by 27 publications

References 51 publications

Multicomponent Composite Membrane with Three-Phase Interface Heterostructure as Photocatalyst for Organic Dye Removal

Multicomponent Composite Membrane with Three-Phase Interface Heterostructure as Photocatalyst for Organic Dye Removal

Keggin Cluster Modulated Photocatalytic Activity of Aryl Sulfonium Polyoxometalate Hybrids toward Dichromate Reduction

Cu–Ag Alloy Nanoparticles in Hydrogel Nanofibers for the Catalytic Reduction of Organic Compounds

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