Bifunctional metal–organic frameworks for the hydrogenation of nitrophenol using methanol as the hydrogen source

Abstract

This work reports the reduction of 4-nitrophenol to 4-aminophenol using UiO-66(Zr) as a bifunctional photocatalyst and hydrogenation catalyst using methanol as the hydrogen source.

MOF-on-MOF Composites with UiO-66-Based Materials as Photocatalysts for the Overall Water Splitting under Sunlight Irradiation

“…The as-prepared MOFs and MOF-on-MOF composites based on UiO-66 topologies (see the Supporting Information) were characterized to ascertain their structural characteristic properties. Powder X-ray diffraction (PXRD) measurements of UiO-66­(Zr)-NH 2 and UiO-66­(Ce) solids confirm the expected UiO-66 topology (Figure ) as previously reported. ,− Furthermore, the diffractions appearing at 2θ values around 4 and 6° are due to the 100 and 110 reflections of the reo topology of UiO-66, , thus indicating the formation of the UiO-66 framework with an ordered structure containing missing cluster defects . These reflections evidence that the reo nanoregions are homogeneously distributed with a long-range order and that the formed UiO-66 structure is close to the reo topology.…”

“…From these UV−vis spectra, the optical band gaps of the UiO-66 materials were determined by means of the Tauc plots (Figure S24). The estimated band gaps for UiO-66(Zr)-NH 2 and UiO-66(Ce) were 2.81 and 2.99 eV, 36,45 respectively, while slightly lower band gap values were obtained for the UiO-66 composites. In addition, the energy level of the valence band maximum of these UiO-66 solids was estimated by XPS from the intersection of a linear fit to the linear portion of the electron emission edge and the background (Figure S25).…”

“…These data are in good agreement with previous studies. 30,36 Further, UiO-66(Zr)-NH 2 -200@UiO-66(Ce) and UiO-66(Zr)-NH 2 -25@UiO-66(Ce) samples exhibited BET surface area values of 841 and 783 m 2 /g, respectively (Figures S3 and S4). Attempts to prepare a UiO-66(Ce)@UiO-66(Zr)-NH 2 composite using 200 mg of preformed UiO-66(Ce) resulted in a crystalline solid (Figure 1d) with a BET surface area of only 600 m 2 /g (Figure S5).…”

Photocatalytic Hydrogen Production from Glycerol Aqueous Solutions as Sustainable Feedstocks Using Zr-Based UiO-66 Materials under Simulated Sunlight Irradiation

“…The photocatalytic activity of the most active UiO-66 solid under study was compared with that of MIL-125(Ti)-NH 2 as reference Ti-MOF [ 52 ]. These four MOFs were prepared by solvothermal method as previously reported and described in the SI [ 49 , 50 ]. Figure 2 shows the characteristic diffraction patterns of the four MOFs under study that are in good agreement with their respective simulated patterns and the thermogravimetric analyses of the MOFs that confirmed the thermal stability up to about 350 °C.…”

“…The MOFs under study, namely, UiO-66(Zr), UiO-66(Zr)-NH 2 , UiO-66(Zr)-NO 2 and MIL-125(Ti)-NH 2 , were prepared according to previously reported procedures [ 49 , 50 ]. Pt NPs (1 wt%) were supported on UiO-66(Zr)-NH 2 by using the photodeposition method.…”