Keggin based self-assembled mesoporous materials for the capture of selective guest molecules

Tandekar, Kesar; Tripathi, Anjali; Muvva, Durga Prasad; Supriya, Sabbani

doi:10.1039/d1ma01092a

Cited by 8 publications

(4 citation statements)

References 110 publications

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“…The characteristic diffraction peaks due to the Keggin clusters of hybrids 1 – 4 appeared in the range 2θ = 7–9°. In addition, broad peaks also appeared in the range 2θ = 15–40°, which are characteristic of Keggin cluster-based hybrids . The differences in the PXRD patterns of hybrids 1 – 4 could be mainly due to the difference in their Keggin cluster type.…”

Section: Resultsmentioning

confidence: 94%

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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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Section: Resultsmentioning

confidence: 94%

“…In addition, broad peaks also appeared in the range 2θ = 15−40°, which are characteristic of Keggin cluster-based hybrids. 36 The differences in the PXRD patterns of hybrids 1−4 could be mainly due to the difference in their Keggin cluster type.…”

Section: ■ Introductionmentioning

confidence: 99%

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

2022

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“…For example, the recently, catalytic properties of different [PW 12-x V x ] n- anions proved to be interesting, especially for the oxidation of organic compounds [ 45 , 46 , 47 ]. Additionally, Keggin compounds with different compositions are recommended to be used in rechargeable batteries [ 46 ] or to fabricate mesoporous materials [ 48 , 49 ].…”

Section: Discussionmentioning

confidence: 99%

Synthesis and Characterisation of Monolacunary Keggin Monovanado-deca-tungstophosphate and Its Complexes with Transition Metal Cations

et al. 2023

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Five new complexes with metal cations (Mn2+, Fe3+, Co2+, Ni2+, and Cu2+) of monolacunary Keggin monovanado-deca-tungstophosphate, K8[PVW10O39]·15H2O, have been synthesised. The molar ratio of the combination between metal cations and K8[PVW10O39]·15H2O has been established to be 1:1, and its general molecular formulas were found to be: Kn[MPVW10O39(H2O)]·xH2O (n = 5 for M = Fe3+ and n = 6 for M = Mn2+, Co2+, Ni2+, and Cu2+). Optimal conditions for complexes’ synthesis (pH, temperature, and reaction time) have been determined. The characterisation of K8[PVW10O39]·15H2O and of its compounds Kn[MPVW10O39(H2O)]·xH2O have been performed using AAS, TG-DTA-DTG, UV-VIS, IR, Raman, and powder XRD methods. In UV spectra, two maximums of absorption were obtained, at 200 and 250 nm, characteristic of Keggin polycondensate compounds. The coordination of cations Ni2+, Co2+, and Cu2+ through oxygen atoms from K8[PVW10O39]·15H2O in an octahedron system has been reflected with VIS spectroscopy. All these methods have proved the compositions and structures of K8[PVW10O39]·15H2O and Kn[MPVW10O39(H2O)]·xH2O, their similarity with other vanadotungstophosphates, and their achievements in the Keggin class. Additionally, all analysis methods have shown an increase in the degree of structural symmetry and the thermal stability of a polyoxoanion complex after attaching metal cations compared to the monolacunary, K8[PVW10O39]·15H2O.

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“…1,2 Their enormous diversity in composition and structure allows them to exhibit good oxidation/reduction and photo-activity and excellent stability, which can be used in many fields such as electrochemistry, magnetism, materials science, catalysis, medicine and photochemistry. [3][4][5][6][7][8][9][10][11][12][13] The negative charge on the surface of a polyoxometalate is stable and its solubility is good. The ability of POMs to reversibly accept and release electrons through valence bond changes in the metal center is one of their most important properties and POMs can be widely used in photochromic materials.…”

Section: Introductionmentioning

confidence: 99%

Three photochromic materials based on POMs and viologens for UV probing, visual detection of metal ions and amine detection

Yang

et al. 2022

CrystEngComm

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Keggin based self-assembled mesoporous materials for the capture of selective guest molecules

Abstract: A series of self-assembled mesoporous materials, compounds 1-9, of the type [RPPh3]n[XM12O40] (R = Ph, Me, Et; n = 3 or 4; X = P, Si; M = Mo, W)...

Cited by 8 publications

References 110 publications

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

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

Synthesis and Characterisation of Monolacunary Keggin Monovanado-deca-tungstophosphate and Its Complexes with Transition Metal Cations

Three photochromic materials based on POMs and viologens for UV probing, visual detection of metal ions and amine detection

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