Pd(/Fe3O4)-on-ZIFs: nanoparticle deposition on (nano-)MOFs from ionic liquids. Issue 22 (28th March 2022)

• Record Type: Journal Article
• Authors: Koikolainen, Olga; Sondermann, Linda; Roitsch, Stefan; Simon, Ilka; Dietrich, Dennis; Gvilava, Vasily; Barthel, Juri; Thomas, Jörg; Janiak, Christoph; Boldog, Ishtvan
• Is Part Of: Journal of materials chemistry. Volume 10:Issue 22(2022)
• Page Start: 11955
• Page End: 11970
• Publication Date: 2022-03-28
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d2ta00883a
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Selected ionic liquids are efficient media for deposition of Pd nanoparticles on nano- or micro- (100–2500 nm) crystals of different zeolitic imidazolate frameworks at 180-230 °C (MW, 1–10 min). Abstract : Well-defined spherical Pd-NPs (∼6–12 nm size, 4–17% wt content) were efficiently deposited on nano- or micro- (∼100–2500 nm) crystals of zeolite imidazolate frameworks (ZIFs) from different ionic liquids (ILs, typically 1-butyl-3-methylimidazolium bistriflimidate, [BMIm]NTf2 ) at 180–230 °C under microwave (MW) heating for 1–10 min. The firm, nearly exclusive on-surface deposition, proven by systematic analysis of TEM micrographs, is achieved via size-exclusion of the IL-solvated PdCl2 precursor. The one-pot high-quality NP deposition from partially stabilizing IL media leads to particularly well-defined metal nanoparticles-on-metal–organic frameworks, MNP-on-MOF(NP)s . They are contraposed to MNP@MOFs or non-specified MNP/MOFs, and are viewed as an extension of MNPs from ionic liquids, securing MNP-agglomeration protection after removal of the IL and reversible redispersion, and offering the functionality of the porous support. Pd-on-ZIF-8-NP (R = Me substituent of the azole ligand) demonstrated the highest stability and morphological quality, while the ZIF-90 analogues with the same sod topology (R = COOH, CHO, CH2 CH2 NH2 ) or the triazolate MAF-66 (R = NH2 ) with dia topology showed lesser stability (particularly for R = COOH and CHO). Ferromagnetic Pd/Fe3 O4 - and Fe3 O4 /Pd-on-ZIF-8-NP, ZIF-90-NH2 (-NP), and MAF-66 composites with nanoparticulated Fe3 O4 (5–13 nm size, 5–22%wt content) demonstrate the feasibility of sequential NP deposition of varied nature. The Pd-on-ZIF composites demonstrated high catalytic activity in the reduction of 4-nitrophenol to 4-aminophenol by NaBH4 in water (TOF 0.38–4.10 vs. 0.088 s −1 for 10%wt Pd/C; amino-functionalization and the presence of Fe3 O4 are a major and a minor factor, respectively). The reduction of the same substrate with H2 in apolar media was much slower for the composite catalysts compared to Pd/C (10%wt ) due to possible poisoning by the residual IL.