Beyond charge separation: The effect of coupling between titanium dioxide and CNTs on the adsorption and photocatalytic reduction of Cr(VI)

Shaham-Waldmann, Nurit; Paz, Yaron

doi:10.1016/j.cej.2013.07.021

Cited by 28 publications

(11 citation statements)

References 57 publications

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“…W 2,(K2Cr2O7) /W 1,(catalyst) , is used for comparison. Under the UV light, TiO 2 -CNT with a W 2 /W 1 value of 0.013 reduced 100% Cr(VI) in 40 min37. Under the visible light, Fe 2 O 3 /g-C 3 N 4 with a W 2 /W 1 value of 0.014 reduced 100% Cr(VI) in 15 min38.…”

Section: Resultsmentioning

confidence: 99%

CuMnOS Nanoflowers with Different Cu+/Cu2+ Ratios for the CO2-to-CH3OH and the CH3OH-to-H2 Redox Reactions

Chen

Abdullah

Kuo

2017

Sci Rep

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A conservative CO2-Methanol (CH3OH) regeneration cycle, to capture and reutilize the greenhouse gas of CO2 by aqueous hydrogenation for industry-useful CH3OH and to convert aqueous CH3OH solution by dehydrogenation for the clean energy of hydrogen (H2), is demonstrated at normal temperature and pressure (NTP) with two kinds of CuMnOS nanoflower catalysts. The [Cu+]-high CuMnOS led to a CH3OH yield of 21.1 mmol·g−1catal.·h−1 in the CuMnOS-CO2-H2O system and the other [Cu+]-low one had a H2 yield of 7.65 mmol·g−1catal.·h−1 in the CuMnOS-CH3OH-H2O system. The successful redox reactions at NTP rely on active lattice oxygen of CuMnOS catalysts and its charge (hole or electron) transfer ability between Cu+ and Cu2+. The CO2-hydrogenated CH3OH in aqueous solution is not only a fuel but also an ideal liquid hydrogen storage system for transportation application.

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Section: Resultsmentioning

confidence: 99%

CuMnOS Nanoflowers with Different Cu+/Cu2+ Ratios for the CO2-to-CH3OH and the CH3OH-to-H2 Redox Reactions

Chen

Abdullah

Kuo

2017

Sci Rep

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“…Waldmann et al studied photocatalytic reduction of Cr(VI) over TiO 2 -coupled CNTs. The reduction rate of Cr(VI) increased due to transfer of photogenerated electrons through CNT surfaces in the absence of sacrificial agents [139]. Huang et al reported that a simultaneous photocatalytic degradation of Cr(VI) and phenol occurs over CNT-modified TiO 2 .The high photoactivity of CNT–TiO 2 may be attributed to the synergistic effect of adsorption and electron trap properties of the CNTs [140].…”

Section: Reviewmentioning

confidence: 99%

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

Acharya

Naik

Parida

2018

Beilstein J. Nanotechnol.

112

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Cr(VI) exhibits cytotoxic, mutagenic and carcinogenic properties; hence, effluents containing Cr(VI) from various industrial processes pose threat to aquatic life and downstream users. Various treatment techniques, such as chemical reduction, ion exchange, bacterial degradation, adsorption and photocatalysis, have been exploited for remediation of Cr(VI) from wastewater. Among these, photocatalysis has recently gained considerable attention. The applications of photocatalysis, such as water splitting, CO2 reduction, pollutant degradation, organic transformation reactions, N2 fixation, etc., towards solving the energy crisis and environmental issues are briefly discussed in the Introduction of this review. The advantages of TiO2 as a photocatalyst and the importance of its modification for photocatalytic reduction of Cr(VI) has also been addressed. In this review, the photocatalytic activity of TiO2 after modification with carbon-based advanced materials, metal oxides, metal sulfides and noble metals towards reduction of Cr(VI) was evaluated and compared with that of bare TiO2. The photoactivity of dye-sensitized TiO2 for reduction of Cr(VI) was also discussed. The mechanism for enhanced photocatalytic activity was highlighted and attributed to the resultant properties, namely, effective separation of photoinduced charge carriers, extension of the light absorption range and intensity, increase of the surface active sites, and higher photostability. Advantages and limitations for photoreduction of Cr(VI) over modified TiO2 are depicted in the Conclusion. The various challenges that restrict the technology from practical applications in remediation of Cr(VI) from wastewater were addressed in the Conclusion section as well. The future perspectives of the field presented in this review are focused on the development of whole-solar-spectrum responsive, TiO2-coupled photocatalysts which provide efficient photocatalytic reduction of Cr(VI) along with their good recoverability and recyclability.

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“…However, a few studies have involved the detection of chromium(VI) anion species (CrO 4 2– or Cr 2 O 7 2– ), which are well-known toxic anions and pose a serious threat to human health and the environment, having been listed as a U.S. Environmental Protection Agency prior pollutant . Nowadays, with the development of industry, more and more poisonous chromium(VI) species are discharged, and they were recognized or removed via conventional methods, such as ion exchange, membrance separation, photocatalytic degradation, etc . Nevertheless, these methods have the defects of poor regeneration and inferior chemical stability.…”

Section: Introductionmentioning

confidence: 99%

Metal–Organic Frameworks with Tb₄ Clusters as Nodes: Luminescent Detection of Chromium(VI) and Chemical Fixation of CO₂

et al. 2017

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Two multifunctional metal-organic frameworks based on cubane-like tetrahedron Tb clusters as nodes have been synthesized and characterized. Compound 1 exhibits a 2D lanthanide-organic framework with Tb clusters as nodes, and compound 2 possesses a 3D framework with Tb clusters and Mn as nodes. Interestingly, luminescent investigations on them reveal that the two compounds can act as recyclable luminescent probes for chromium(VI) anion species and the corresponding detection limit can reach 10 mol/L. Furthermore, 1 and 2 own efficient catalytic activity for the chemical fixation of CO with epoxides under mild conditions. Importantly, they both can be recycled at least three times without compromising the activity.

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Beyond charge separation: The effect of coupling between titanium dioxide and CNTs on the adsorption and photocatalytic reduction of Cr(VI)

Cited by 28 publications

References 57 publications

CuMnOS Nanoflowers with Different Cu+/Cu2+ Ratios for the CO2-to-CH3OH and the CH3OH-to-H2 Redox Reactions

CuMnOS Nanoflowers with Different Cu+/Cu2+ Ratios for the CO2-to-CH3OH and the CH3OH-to-H2 Redox Reactions

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

Metal–Organic Frameworks with Tb₄ Clusters as Nodes: Luminescent Detection of Chromium(VI) and Chemical Fixation of CO₂

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Beyond charge separation: The effect of coupling between titanium dioxide and CNTs on the adsorption and photocatalytic reduction of Cr(VI)

Cited by 28 publications

References 57 publications

CuMnOS Nanoflowers with Different Cu+/Cu2+ Ratios for the CO2-to-CH3OH and the CH3OH-to-H2 Redox Reactions

CuMnOS Nanoflowers with Different Cu+/Cu2+ Ratios for the CO2-to-CH3OH and the CH3OH-to-H2 Redox Reactions

Cr(VI) remediation from aqueous environment through modified-TiO2-mediated photocatalytic reduction

Metal–Organic Frameworks with Tb4 Clusters as Nodes: Luminescent Detection of Chromium(VI) and Chemical Fixation of CO2

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Product

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Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

Metal–Organic Frameworks with Tb₄ Clusters as Nodes: Luminescent Detection of Chromium(VI) and Chemical Fixation of CO₂