Assembling Ultrafine SnO2 Nanoparticles on MIL-101(Cr) Octahedrons for Efficient Fuel Photocatalytic Denitrification

Abstract

Effectively reducing the concentration of nitrogen-containing compounds (NCCs) remains a significant but challenging task in environmental restoration. In this work, a novel step-scheme (S-scheme) SnO2@MCr heterojunction was successfully fabricated via a facile hydrothermal method. At this heterojunction, MIL-101(Cr) octahedrons are decorated with highly dispersed SnO2 quantum dots (QDs, approximate size 3 nm). The QDs are evenly wrapped around the MIL-101(Cr), forming an intriguing zero-dimensional/three-dimensional (0D/3D) S-scheme heterostructure. Under simulated sunlight irradiation (280 nm < λ < 980 nm), SnO2@MCr demonstrated superior photoactivity toward the denitrification of pyridine, a typical NCC. The adsorption capacity and adsorption site of SnO2@MCr were also investigated. Tests using 20%SnO2@MCr exhibited much higher activity than that of pure SnO2 and MIL-101(Cr); the reduction ratio of Cr(VI) is rapidly increased to 95% after sunlight irradiation for 4 h. The improvement in the photocatalytic activity is attributed to (i) the high dispersion of SnO2 QDs, (ii) the binding of the rich adsorption sites with pyridine molecules, and (iii) the formation of the S-scheme heterojunction between SnO2 and MIL-101(Cr). Finally, the photocatalytic mechanism of pyridine was elucidated, and the possible intermediate products and degradation pathways were discussed.

Amino-functionalized MIL-125(Ti) for photodenitrification of pyridine in fuels via coordination activation by unsaturated Ti4+ centers

“…CO 2 and NH 3 ). 45,46 On the basis of these results, a possible denitrification mechanism of pyridine is proposed and illustrated in Fig. 8(d).…”

“…CO 2 and NH 3 ). 45,46 On the basis of these results, a possible denitrification mechanism of pyridine is proposed and illustrated in Fig. 8 Based on the above experimental results and theoretical calculations, a probable mechanism was proposed.…”

One-Pot Synthesis of N-Doped NiO for Enhanced Photocatalytic CO2 Reduction with Efficient Charge Transfer

“…In addition, the binding energies of 860.6 and 870.7 eV corresponded to the satellite peaks of Ni 2p [ 39 ]. However, compared with the NiO, the Ni 2p characteristic peak of N-NiO-2 shifted 0.59 eV in the direction of increased binding energy, indicating a decrease in the electron-cloud density of the Ni element [ 40 ]. This may have been due to the fact that the electronegativity of N is larger than that of Ni, and electrons are more easily attracted by the N element.…”

Embedding of copper(i) oxide quantum dots in MOF-801 for the photocatalytic degradation of acid yellow 23 under visible light

“…The applications of QDs@MOFs nanocomposite include photocatalysis, catalysis, electrocatalysis sensing, bioimaging, optoelectronics, and batteries. 13 The QDs@MOFs nanocomposite such as GQDs@UiO-66-NH 2 , 30,31 CDs@ZIF-8, 32 CdSQDs@ZIF-8, 33 CdSQDs@MIL-125-NH 2 , 34 BiOQDs@In-MIL-68, 35 CsPbBr 3 QDs@PCN-333(Fe), 36 Cs 3 Bi 2 I 9 QDs@NH 2 -UiO-66, 37 S,NGQDs@UiO-66, 38 CDs@NH 2 -MIL-125(Ti), 39 SnO 2 @MIL-101(Cr), 40 and ZnOQDs@ZIF-8@MIL-68(In) 41 have been used in photocatalytic applications. 13 To prevent QD aggregation on MOF surfaces, the double solvents method (DSM) has been commonly used.…”