Study of the enhanced visible-light-sensitive photocatalytic activity of Cr2O3-loaded titanate nanosheets for Cr(<scp>vi</scp>) degradation and H2 generation

Ding, Jian; Ming, Julan; Lu, Dingze; Wu, Wenhui; Liu, Min; Zhao, Xiaona; Li, Chunhe; Yang, Minchen; Fang, Pengfei

doi:10.1039/c7cy00644f

Cited by 43 publications

(12 citation statements)

References 58 publications

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“…The photocatalytic reduction of Cr(VI) to Cr(III) is regarded as an efficient and promising approach for the removal of Cr(VI) in wastewater because of its economic cost and environmental friendliness. − Many researchers have invested much effort in developing photocatalysts for the reduction of Cr(VI). For example, the commonly used photocatalysts consist of titanium dioxide, zinc oxide (ZnO), metal sulfides (CdS and SnS 2 ), etc.…”

Section: Introductionmentioning

confidence: 99%

Reduced Phosphomolybdate Hybrids as Efficient Visible-Light Photocatalysts for Cr(VI) Reduction

Hua

Zhang

et al. 2019

Inorg. Chem.

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Photocatalytic reduction of hexavalent chromium [Cr(VI)] is a promising technology approach to highly efficiently and environmentally tackle the problem of Cr(VI) pollution, in which the key challenge is in the development of effective photocatalysts. In this work, highly reduced hourglass-type molybdophosphate hybrids with the formulas [Zn(mbpy)(H2O)2]2[Zn(mbpy)(H2O)]2{Zn[P4Mo6O31H7]2}·9H2O (1), [Na(H2O)2]2[Zn(mbpy)(H2O)]2[Zn(mbpy)(H2O)2]2{Zn[P4Mo6O31H6]2}·15H2O (2), and (H2mbpy){[Zn(mbpy)(H2O)]2[Zn(H2O)]2}{Zn[P4Mo6O31H6]2}·10H2O (3) (mbpy = 4,4′-dimethyl-2,2′-bipyridine) have been hydrothermally synthesized and used as photocatalysts for the reduction of Cr(VI) under mild conditions. Structural analysis showed that the inorganic moieties in crystals 1–3 are composed of a unique 0D single cluster form, a 1D chainlike structure, and a 2D-layered structure, respectively, in which polyanions were constructed by hourglass-type molybdophosphates with one Zn(II) ion as the central metal. These hybrids displayed good performance for the photocatalytic reduction of Cr(VI) by virtue of their wide visible-light adsorption, suitable energy band structures, and specific spatial arrangements of polyanionic species. Among them, hybrid 2 exhibits the best photocatalytic performance with a Cr(VI) reduction conversion rate of almost 94.7% within 180 min of reaction time. The photocatalysis mechanism investigation revealed that highly reduced hourglass-type molybdophosphate clusters can be illuminated by visible light. The photoinduced electrons induced by hourglass-type polyanions can directly reduce Cr(VI) to Cr(III), while the photogenerated holes are used to oxidize the sacrificial agent isopropyl alcohol to acetone. This work provides new guidance for the design and preparation of highly efficient photocatalysts for the reduction of Cr(VI).

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Section: Introductionmentioning

confidence: 99%

Reduced Phosphomolybdate Hybrids as Efficient Visible-Light Photocatalysts for Cr(VI) Reduction

Hua

Zhang

et al. 2019

Inorg. Chem.

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“…Furthermore, the same experiments were reproduced in the presence of different scavengers for charge carriers and radicals to investigate the role of radicals in the photocatalytic reactions. Potassium iodide (KI), isopropanol (IPA), and 1,4-benzoquinone (BQ) were selected as holes, hydroxyl radicals (OH), and superoxide radicals ( • O 2– ) scavengers, respectively. − The concentration of KI, IPA, and BQ was 4 × 10 –4 , 1 × 10 –3 , and 1 × 10 –3 M, respectively.…”

Section: Experimental Sectionmentioning

confidence: 99%

Nickel Oxide Selectively Deposited on the {101} Facet of Anatase TiO₂ Nanocrystal Bipyramids for Enhanced Photocatalysis

Kashiwaya

Olivier

Majimel

et al. 2019

ACS Appl. Nano Mater.

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Facet-engineered anatase TiO2 with NiO nanoparticles heterocontacts were successfully prepared by selective photodeposition of NiO nanoparticles onto the {101} facet of the top-truncated bipyramidal TiO2 anatase nanocrystals coexposed with {001} and {101} facets. The morphology and electronic properties of the resulting 0.1–10 wt % NiO-decorated TiO2 were investigated by X-ray diffraction, high-resolution electron microscopy, N2 sorption analysis, and UV–vis spectroscopy. Furthermore, a careful determination of the energy band alignment diagram was conducted by a model experiment using XPS and UPS to verify charge separation at the interface of the NiO−TiO2 heterostructure. The model experiment was performed by stepwise deposition of NiO onto oriented TiO2 substrates and in-situ photoelectron spectroscopy measurements without breaking vacuum. Core levels showed shifts of 0.58 eV toward lower binding energies, meaning an upward band bending in TiO2 at the NiO–TiO2 interface. Furthermore, 0.1 wt % NiO–TiO2 exhibited 50% higher activities than the pure TiO2 for methylene blue (MB) photodecomposition under UV irradiation. This enhanced photocatalytic activity of NiO–TiO2 nanocomposites was related to the internal electric field developed at the p–n NiO−TiO2 heterojunction, leading to vectorial charge separation. Finally, mechanistic studies conducted in the presence of carrier or radical scavengers revealed that holes dominantly contributed to the photocatalytic reactions in the case of NiO–TiO2 photocatalysts while electrons played the main role in photocatalysis for the pure TiO2 materials.

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“…Therefore, exploring an efficient approach to dispose Cr(VI) is especially urgent and crucial. Visible‐light driven photocatalytic Cr(VI) reduction reaction has been considered as a low‐cost, efficient and environmental friendly pathway for Cr(VI) treatment [7–10] . However, most of previous studies in photocatalysts are limited by their low activities under visible light, necessitating to develop more efficient visible‐light‐driven catalysts for Cr(VI) reduction [11–15] …”

Section: Introductionmentioning

confidence: 99%

Organic Moiety‐Regulated Photocatalytic Performance of Phosphomolybdate Hybrids for Hexavalent Chromium Reduction

Zhang

Hua

et al. 2021

Chemistry An Asian Journal

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Visible‐light‐driven photocatalytic Cr(VI) reduction is a promising pathway to moderate environmental pollution, in which the development of photocatalysts is pivotal. Herein, three hourglass‐type phosphomolybdate‐based hybrids with the formula of: (H2bpe)3[Zn(H2PO4)][Zn(bpe)(H2O)2]H{Zn[P4Mo6O31H6]2} ⋅ 6H2O (1) Na6[H2bz]2[ZnNa4(H2O)5]{Zn [P4Mo6O31H3]2} ⋅ 2H2O (2) and (H2mbpy) {[Zn(mbpy)(H2O)]2[Zn(H2O)]2}{Zn[P4Mo6O31H6]2} ⋅ 10H2O (3) (bpe=trans‐1,2‐bi(4‐pyridyl)‐ethylene; bz=4,4′‐diaminobiphenyl; mbpy=4,4’‐dimethyl‐2,2’bipyridine) were synthesized under the guidance of the functional organic moiety modification strategy. Structural analysis showed that hybrids 1–3 have similar 2D layer‐like spatial arrangements constructed by {Zn[P4Mo6]2} clusters and organic components with different conjugated degree. With excellent redox properties and wide visible‐light absorption capacities, hybrids 1–3 display favourable photocatalytic activity for Cr(VI) reduction with 79%, 70% and 64% reduction rates, which are superior to that of only inorganic {Zn[P4Mo6]2} itself (21%). The investigation of organic components on photocatalytic performance of hybrids 1–3 suggested that the organic counter cations (bpe, bz and mbpy) can effectively affect the visible‐light absorption, as well as the recombination of photogenerated carriers stemmed from {Zn[P4Mo6]2} clusters, further promoting their photocatalytic performances towards Cr(VI) reduction. This work provides an experimental basis for the design of functionalized photocatalysts via the modification of organic species.

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Study of the enhanced visible-light-sensitive photocatalytic activity of Cr₂O₃-loaded titanate nanosheets for Cr(vi) degradation and H₂ generation

Abstract: Cr2O3-loaded titanate nanosheets with large surface area show excellent visible-light catalytic activity for Cr(vi) degradation and H2 generation.

Cited by 43 publications

References 58 publications

Reduced Phosphomolybdate Hybrids as Efficient Visible-Light Photocatalysts for Cr(VI) Reduction

Reduced Phosphomolybdate Hybrids as Efficient Visible-Light Photocatalysts for Cr(VI) Reduction

Nickel Oxide Selectively Deposited on the {101} Facet of Anatase TiO₂ Nanocrystal Bipyramids for Enhanced Photocatalysis

Organic Moiety‐Regulated Photocatalytic Performance of Phosphomolybdate Hybrids for Hexavalent Chromium Reduction

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Study of the enhanced visible-light-sensitive photocatalytic activity of Cr2O3-loaded titanate nanosheets for Cr(vi) degradation and H2 generation

Abstract: Cr2O3-loaded titanate nanosheets with large surface area show excellent visible-light catalytic activity for Cr(vi) degradation and H2 generation.

Cited by 43 publications

References 58 publications

Reduced Phosphomolybdate Hybrids as Efficient Visible-Light Photocatalysts for Cr(VI) Reduction

Reduced Phosphomolybdate Hybrids as Efficient Visible-Light Photocatalysts for Cr(VI) Reduction

Nickel Oxide Selectively Deposited on the {101} Facet of Anatase TiO2 Nanocrystal Bipyramids for Enhanced Photocatalysis

Organic Moiety‐Regulated Photocatalytic Performance of Phosphomolybdate Hybrids for Hexavalent Chromium Reduction

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Study of the enhanced visible-light-sensitive photocatalytic activity of Cr₂O₃-loaded titanate nanosheets for Cr(vi) degradation and H₂ generation

Nickel Oxide Selectively Deposited on the {101} Facet of Anatase TiO₂ Nanocrystal Bipyramids for Enhanced Photocatalysis