Details

Autor(en) / Beteiligte

• Razafintsalama, A. Rija
• Mishra, Rajashree P.
• Sahoo, Manas K.
• Mrinalini, Madoori
• Sahoo, Bismaya
• Ravelonandro, Pierre
• Chaudhary, Yatendra S.

Titel

Efficient Photocatalytic Reduction of Hexavalent Chromium by BiVO4‑Decorated MXene Photocatalysts and Their Charge Carrier Dynamics

Ist Teil von

• Langmuir, 2023-09, Vol.39 (36), p.12725-12739

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The synergistically MXene (Ti 3 C 2 T x ) co-catalyst-decorated BiVO 4 -based heterostructured photocatalysts have been synthesized by a hydrothermal approach with varied loading concentrations of MXene (Ti 3 C 2 T x ) to drive the hexavalent chromium reduction efficiently. The formation of the heterostructured photocatalyst was confirmed by the appearance of X-ray diffraction (XRD) peaks corresponding to the monoclinic BiVO 4 phase and MXene (Ti 3 C 2 T x ) and also the antisymmetric (834 cm–1) and symmetric stretching (715 cm–1) of tetrahedral VO4 and D (1330 cm–1) and G (1570 cm–1) bands corresponding to MXene (Ti 3 C 2 T x ) in the Raman spectrum. The worm-like structures of BiVO 4 nanocrystals grew onto the lamellar sheets of MXene (Ti 3 C 2 T x ), as shown by field emission scanning electron microscopy (FESEM), and has an increased surface area of 15.62 m2g-1 in the case of BVO-20-TC. X-ray photoelectron spectroscopy (XPS) analysis confirms the presence of V5+ and Ti3+states, and the uniform distribution of BiVO 4 nanocrystals over lamellar sheets of MXene (Ti 3 C 2 T x ) is evident from energy-dispersive X-ray (EDX) analysis. The ultraviolet-diffuse reflectance spectroscopy (UV-DRS) spectra suggest a decrease in the band gap energy of BVO-20-TC to 2.335 eV, promoting a higher degree of visible light harvesting. Upon optimization, by varying the pH, the amount of the photocatalyst, and the concentration of Cr­(IV), BVO-20-TC exhibits the highest photocatalytic efficiency (96.39%) while using a Cr­(VI) concentration of 10 ppm at pH 2 and 15 mg of the photocatalyst, and the photoreduction of Cr­(VI) to Cr­(III) follows the pseudo-first-order reaction. The decrease in the PL intensity in BVO-20-TC reveals a faster transfer of electrons from MXene (Ti 3 C 2 T x ) to BiVO 4 . Further, the higher degree of band bending at the BiVO 4 /MXene (Ti 3 C 2 T x ) heterojunction, revealed from the Mott–Schottky analysis, facilitates efficient charge transfer and eventually faster and efficient photoreduction of Cr­(VI) to Cr­(III). The reusability and stability test undertaken for BVO-20-TC reveals that even after five cycles, the Cr (VI) photoreduction efficacy is retained. This work provides insights into photoreduction of Cr (VI) by using such heterostructures.