Volume 4, Issue 4, Pages 845-856 (April 2018) Quasi-MOF: Exposing Inorganic Nodes to Guest Metal Nanoparticles for Drastically Enhanced Catalytic Activity  Nobuko Tsumori, Liyu Chen, Qiuju Wang, Qi-Long Zhu, Mitsunori Kitta, Qiang Xu  Chem  Volume 4, Issue 4, Pages 845-856 (April 2018) DOI: 10.1016/j.chempr.2018.03.009 Copyright © 2018 Elsevier Inc. Terms and Conditions

Chem 2018 4, 845-856DOI: (10.1016/j.chempr.2018.03.009) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 1 Schematic Illustration, TGA, PXRD, and IR Characterizations (A) Schematic illustration showing the synthesis of Au/quasi-MIL-101 through controlled deligandation of Au/MIL-101. (B) TGA plots of Au/MIL-101 isothermally maintained at the respective temperatures (i.e., 373, 473, 573, 673, and 1,073 K) each for 1 hr. (C) PXRD patterns of MIL-101, Au/MIL-101, and Au/MIL-101(x). (D) FTIR spectra of MIL-101, Au/MIL-101, Au/MIL-101(x), and Cr2O3. Chem 2018 4, 845-856DOI: (10.1016/j.chempr.2018.03.009) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 2 HAADF-STEM and XPS Characterizations (A) HAADF-STEM image of Au/MIL-101. See also Figure S1. (B) HAADF-STEM image of Au/MIL-101(573). See also Figure S4. (C and D) XPS spectra of MIL-101, Au/MIL-101, and Au/MIL-101(573) referenced to the hydrocarbon C 1s at Cr 2p (C) and Au 4f (D). See also Figure S15. Chem 2018 4, 845-856DOI: (10.1016/j.chempr.2018.03.009) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 3 Catalytic Activity in CO Oxidation (A) Catalytic performance of Au/MIL-101, 11.6 wt % Au/MIL-101(x) prepared by calcination for 1 hr, MIL-101(573), and Au/Cr2O3(573) in CO oxidation at 298 K. (B) Catalytic performance of 11.6 wt % Au/MIL-101(573) prepared at various calcination durations (i.e., 5, 15, 30, 60, and 180 min) in CO oxidation at 298 K. (C) Conversion of CO to CO2 as a function of reaction temperature over Au/MIL-101(573) calcined for 30 min with different amounts of catalyst (i.e., 0.025, 0.05, and 0.1 g) at a reaction gas flow rate of 33 mL min−1. (D) CO oxidation at various temperatures catalyzed by Au/MIL-101(573) calcined for 30 min. Chem 2018 4, 845-856DOI: (10.1016/j.chempr.2018.03.009) Copyright © 2018 Elsevier Inc. Terms and Conditions

Scheme 1 Schematic Illustration of the Calcination-Induced Structure Changes of the Metal/MOF Composites At 373 K, the guest H2O molecules are released from MIL-101. At 473 K, accessible Cr–O sites are created upon removal of the coordinated H2O molecules and OH/F groups. More accessible Cr–O sites on “quasi-MIL-101” can be fabricated at 573 K as a result of the release of CO2 on the terephthalate ligand. However, a harsh temperature above 673 K results in the collapse of the framework. The deligandation-induced accessible Cr–O sites can uptake and activate O2 molecules and then release active oxygen species to the CO molecules adsorbed on the Au NPs near the Cr–O sites for the oxidation of CO. Chem 2018 4, 845-856DOI: (10.1016/j.chempr.2018.03.009) Copyright © 2018 Elsevier Inc. Terms and Conditions