Selective Palladium‐Loaded MIL‐101 Catalysts

Abstract

Palladium nanoparticles (NPs) of different mean particle size have been synthesized in the host structure of the porous coordination polymer (or metal-organic framework: MOF) MIL-101. The metal-organic chemical vapor deposition method was used to load MIL-101 with the Pd precursor complex [(η(5)-C(5)H(5))Pd(η(3)-C(3)H(5))]. Loadings higher than 50 wt.% could be accomplished. Reduction of the Pd precursor complex with H(2) gave rise to Pd NPs inside the MIL-101 (Pd@MIL-101). The reduction conditions, especially the temperature, allows us to make size-conform (size of the Pd NPs correlates with the size of the cavities of the host structure of MIL-101) and undersized Pd NPs. The Pd@MIL-101 samples were characterized by X-ray diffraction, IR spectroscopy, Brauner-Emmett-Teller (BET) analysis, elemental analysis, and transmission electron microscopy (TEM). Catalytic studies, hydrogenation of ketones, were performed with selected Pd@MIL-101 catalysts. Activity, selectivity, and recyclability of the catalyst family are discussed.

Facile synthesis of palladium nanoparticles encapsulated in amine-functionalized mesoporous metal–organic frameworks and catalytic for dehalogenation of aryl chlorides

“…3) indicate that Pd 0 and Cr III coexist in the Pd/MIL-101(Cr)-NH 2 materials. In the XPS traces, the 3d 5/2 and 3d 3/2 peaks of Pd 0 appear at 336.7 and 341.7 eV and no obvious peak of Pd 2+ is observed, which indicates that most of the palladium is in the reduced form [38][39][40][41][42][43][44][45][46][47][48].…”

“…The results indicate that the cavities of MIL-101(Cr)-NH 2 may be occupied by palladium NPs and/or blocked by palladium NPs that are located at the surface [38][39][40][41][42][43][44][45][46][47][48]. X-ray photoelectron spectroscopy (XPS) (Fig.…”

“…Inclusion of metallic nanoparticles in MOFs still remains a challenge [38][39][40][41][42][43][44][45][46][47][48]. So far, there are only a handful of MOF materials as host matrices to support metal NPs as catalysts for heterogeneous catalysis [37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] 3 ÁnH 2 O (n % 25) for the success of encapsulation of noble metal nanoparticles [39]. We also synthesized well-dispersed Pd nanoparticles (Pd NPs) supported on the amino-functionalized MOF MIL-53(Al)-NH 2 (Al(OH)[H 2 N-BDC], H 2 N-BDC = 2-aminoterephthalic acid, MIL = Materials of Institut Lavoisier) using a direct anionic exchange approach [52,53].…”

Application of metal and metal oxide nanoparticles@MOFs

“…As can be seen in Table 1, the most active metal nanoparticles for these reactions are Pt and Pd, and the most promising MOF support is MIL-101 most probably due to its stability and large pore channels. Using this combination, excellent conversion rates (~ 100%) for the hydrogenation of ketones, aromatic molecules, alkenes, alkynes and nitro compounds have been observed [83,[86][87][88][89][90][91][92][93].…”

Chemistry of Metal-organic Frameworks Monitored by Advanced X-ray Diffraction and Scattering Techniques

“…These nanoparticles were usually identified by the conventional X-ray powder diffraction. [137][138][139][140][141][142][143] Recently, the method of high-energy Xray total scattering (XTS) was employed for the investigation of low-concentration of nanoparticles within the matrix. The different amounts of Pd nanoparticles were immobilized within the MIL-101(Cr)-NH 2 material for Suzuki-Miyaura catalytic reactions.…”