Construction of novel Pd/CeO2/g-C3N4 nanocomposites as efficient visible-light photocatalysts for hexavalent chromium detoxification

AbstractIn the present study, alkaline hydrothermally treated titania nanoparticles (TiO2-HT) are prepared and followed by calcination at different low temperatures to improve TiO2 activity under visible light. The prepared photocatalysts (PCs) are characterized by different tools. TiO2-HT is scrutinized for decontamination of para-nitrophenol (PNP) and hexavalent chromium ions (Cr6+ ions) under simulated sunlight. TiO2-HT-300 and TiO2-HT-400 PCs have nanosized particle with large surface area of 148 and 116.26 m2/g, respectively. Additionally, XRD and FTIR proved formation of nanocrystalline anatase TiO2. The different calcined TiO2-HT materials show lower adsorption capacity for PNP and Cr6+ ions. TiO2-HT-300 and HT-TiO2-400 PCs have higher reduction rate of PNP than that of uncalcined temperature titania (HT-TiO2-U) powder. Complete conversion of PNP is achieved at natural pH after 180 min over TiO2-HT-300. As well, TiO2-HT-300 exhibits a superior photocatalytic removal of Cr6+ ions. The enhanced photocatalytic efficacy is ascribed to the synergism between higher surface area and particle size (quantum effect) of TiO2-HT-300. As results, HO· radicals are the main key active species for the photocatalytic degradation of PNP over TiO2- HT-300 PC but contribution of O2– and h+ holes is minor. The used method for preparation of TiO2-HT-300 reduces the cost preparation as well as environmental impact reduction. Finally, low temperature-calcined TiO2 is promising visible light active and an efficient photocatalyst with lower environmental impact for detoxification of PNP and Cr6+ ions from water.

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Bi2S3-sensitized TiO2 nanostructures prepared by solution process for highly efficient photoreduction of hexavalent chromium ions in water under visible light

Optical Materials ◽

10.1016/j.optmat.2021.111964 ◽

2022 ◽

Vol 124 ◽

pp. 111964

Author(s):

Ahmed Shawky ◽

Nadiyah Alahmadi ◽

R.M. Mohamed ◽

Z.I. Zaki

Keyword(s):

Visible Light ◽

Hexavalent Chromium ◽

Solution Process ◽

Chromium Ions ◽

Highly Efficient ◽

Tio2 Nanostructures

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Photocatalytic reduction of hexavalent chromium with commercial Fe/Ti oxide catalyst under UV and visible light irradiation

International Journal of Environmental Science and Technology ◽

10.1007/s13762-017-1628-0 ◽

2017 ◽

Vol 15 (11) ◽

pp. 2459-2472 ◽

Cited By ~ 2

Author(s):

M. M. S. Sanad ◽

E. A. Abdel-Aal ◽

H. M. Osman ◽

A. T. Kandil

Keyword(s):

Visible Light ◽

Hexavalent Chromium ◽

Visible Light Irradiation ◽

Oxide Catalyst ◽

Photocatalytic Reduction ◽

Light Irradiation

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Titania-based heterogeneous photocatalysis. Materials, mechanistic issues, and implications for environmental remediation

Pure and Applied Chemistry ◽

10.1351/pac200173121849 ◽

2001 ◽

Vol 73 (12) ◽

pp. 1849-1860 ◽

Cited By ~ 72

Author(s):

Krishnan Rajeshwar ◽

C. R. Chenthamarakshan ◽

Scott Goeringer ◽

Miljana Djukic

Keyword(s):

Methylene Blue ◽

Visible Light ◽

Hexavalent Chromium ◽

Environmental Remediation ◽

Catalytic Properties ◽

Heterogeneous Photocatalysis ◽

The Other ◽

Tio2 Surface ◽

Tio2 Sample

Using hexavalent chromium [Cr(VI)] and methylene blue (MB) as model substrates, we discuss three aspects of TiO2-based heterogeneous photocatalysis. We show first that a given TiO2 sample may not be simultaneously optimal for photocatalytically driving the reduction of Cr(VI) and the oxidation of MB. We further show that a TiO2 sample that strongly adsorbs either of these substrates in the dark is not optimal as a photocatalyst. The other two aspects concern circumventing the rather poor surface catalytic properties and visible light photoresponse of TiO2, respectively. Strategies revolving around the visible light photoexcitation of the substrate itself and metal-modification of the TiO2 surface, are described as possible solutions.

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