UiO-66-NH₂ Octahedral Nanocrystals Decorated with ZnFe₂O₄ Nanoparticles for Photocatalytic Alcohol Oxidation

Abstract

Photocatalytic selective oxidation of alcohols to aldehydes under mild conditions (atmospheric pressure and room temperature) remains a huge challenge, especially for nanoscale catalysts without precious metals. Herein, ZnFe2O4/UiO-66-NH2 (ZFO/U6N) composites are fabricated via an electrostatic self-assembly process, which follows the Z-scheme interfacial charge transfer pattern. Ultrasmall ZFO nanoparticles are anchored to the surface of U6N uniformly due to the large potential difference, forming a tight heterogenous interface for efficient charge transfer and separation. The optimized ZFO/U6N composite possesses excellent conversion (68%) and selectivity (99%) for photocatalytic oxidation of benzyl alcohol to benzaldehyde in an air atmosphere with AM 1.5G as a light source at room temperature. The fantabulous photocatalytic activity can be ascribed to the Z-scheme charge transfer stratagem, improving the charge transfer and separation efficiency, which can maintain the oxidizing ability of holes in the highest occupied molecular orbital energy level of U6N and the reducibility of electrons in the conduction band of ZFO nanoparticles. In addition, after five recycles, the photocatalytic performance of ZFO/U6N nearly remains constant, indicating the high stability. This work provides a strategy for the optimizing nanoscale photocatalysts for photocatalytic selective oxidation reactions under mild conditions.

Porphyrin Supramolecular Nanoassembly/C3N4 Nanosheet S-Scheme Heterojunctions for Selective Photocatalytic CO2 Reduction toward CO

“…To further disclose the conduction band (CB) positions of the CN and ZnTP, Mott− Schottky measurements were carried out at different frequencies (Figure 4b,c). The positive slopes of the plots demonstrated typical characteristics of n-type semiconductors; 48,49 thus, the CB potentials of CN and ZnTP are estimated to be −0.83 and −1.06 V versus Ag/AgCl, respectively. By combining the optical band gaps and obtained CB potentials, the valence band (VB) positions of CN and ZnTP are 1.72 and 0.55 eV, respectively.…”

Hierarchical S-Scheme Heterostructure of CdIn2S4@UiO-66-NH2 toward Synchronously Boosting Photocatalytic Removal of Cr(VI) and Tetracycline

“…In the pristine U66N, the peaks at 1570 and 1385 cm –1 originate from the asymmetric stretching vibration and symmetric stretching vibration of the O–C–O bond on the ligand of 2-aminoterephthalic acid . The absorption bands at 1492 and 1438 cm –1 correspond to the typical CC vibration in the benzene ring and the C–C vibration in the organic ligand in U66N, respectively. , The peak at 1256 cm –1 can be attributed to C–N stretching absorption, and the two peaks at 767 and 660 cm –1 can be assigned to the Zr–O vibration in U66N. , From the FT-IR spectra of CIS@U66N, we can discern the typical peaks of CIS at 1623 cm –1 and the characteristic peaks of U66N corresponding with those of pure U66N, which further affirms the coexistence of CIS and U66N in these hybrids.…”

“…39,40 The peak at 1256 cm −1 can be attributed to C−N stretching absorption, and the two peaks at 767 and 660 cm −1 can be assigned to the Zr−O vibration in U66N. 41,42 From the FT-IR spectra of CIS@U66N, we can discern the typical peaks of CIS at 1623 cm −1 and the characteristic peaks of U66N corresponding with those of pure U66N, which further affirms the coexistence of CIS and U66N in these hybrids.…”

Hierarchical UiO-66(−NH2)/CuInS2 S-Scheme Photocatalyst with Controlled Topology for Enhanced Photocatalytic N2 Fixation and H2O2 Production

“…To explore the influence of CIS on the optical features of the UN66, UV–vis DRS spectral analysis is performed. The pure UN66 displays three absorption bands at 262, 320, and 443 nm, that are attributed to Zr–O nodes, n−π* electronic transition of the amino group present in the organic linker, and ATA to Zr charge transfer, respectively, , while the pristine CIS material displays strong absorption in the entire UV–vis region which extends up to the near-infrared region. In contrast, the UN66/CIS­(X) hybrid materials exhibit a successive shifting of the absorption band toward a higher wavelength as compared to pure UN66 (Figure a).…”