Nanoparticles@metal–organic frameworks (MOFs) composites have attracted considerable attention in recent years due to the prominent selective catalytic activity. However, it is highly desirable to ...develop a simple and universal way to settle the trade‐off between the catalytic efficiency and selectivity. Herein, by employing the thermal instability of inherent defects, hierarchically porous Pt@UiO‐66‐NH2, Pt@UiO‐66, Pt@ZIF‐8, and Au@ZIF‐8 are successfully constructed after annealing at an appropriate temperature, respectively. The generated mesopores in the MOFs can be located around the external nanoparticle to retain the MOF shell for catalytic selectivity. Finally, when tested in olefin hydrogenation, Pt@UiO‐66‐NH2 shows significantly improved catalytic rate and enhanced dynamic selectivity.
A series of nanoparticles@metal–organic frameworks (MOFs) composites with hierarchical porosity is achieved by employing the thermal instability of inherent defects of the nanoparticles@MOFs. The generated mesopores can be located around the external nanoparticles to retain the MOF shell for catalytic selectivity. When tested in olefin hydrogenation, the resulting nanoparticles@MOFs composites exhibit improved catalytic rate and enhanced dynamic selectivity.
Herein, we report a stable catalyst with Ru single atoms anchored on a one-dimensional carbon fiber@graphitic carbon nitride hierarchy, by assembling wet wipes composed of fiber-derived carbon fiber ...(CF), melamine-derived graphitic carbon nitride (g-C3N4) and RuCl3 before NaBH4 reduction. The atomically dispersed Ru species (3.0 wt%) are tightly attached via N-coordination provided by exterior g-C3N4 nanosheets, and further stabilized by the interior mesoporous CF. The obtained CF@g-C3N4–Ru SAs catalyst can be cycled six times without notable leaching of Ru or loss of GVL yield in the acidic media. This catalyst is more stable than Ru nanoparticles supported on CF@g-C3N4, as well as Ru single atoms anchored on CF and g-C3N4, and proves to be one of the most efficient metal catalysts for aqueous LA hydrogenation to γ-valerolactone (GVL). The isolated Ru atoms by strong N-coordination, and their enhanced electron/mass transfer afforded by the one-dimensional hierarchy, can be responsible for the excellent durability of CF@g-C3N4–Ru SAs under harsh reaction conditions.
Supported metal oxide nanoparticles are important in heterogeneous catalysis; however, the ability to tailor their size, structure, and dispersion remains a challenge. A strategy to achieve ...well‐dispersed and size‐controlled supported metal oxides through the manageable growth of a metal organic framework (Cu–BTC) on TiO2 followed by pyrolysis is described.
Abstract
Hydrogen spillover is the migration of activated hydrogen atoms from a metal particle onto the surface of catalyst support, which has made significant progress in heterogeneous catalysis. ...The phenomenon has been well researched on oxide supports, yet its occurrence, detection method and mechanism on non-oxide supports such as metal–organic frameworks (MOFs) remain controversial. Herein, we develop a facile strategy for efficiency enhancement of hydrogen spillover on various MOFs with the aid of water molecules. By encapsulating platinum (Pt) nanoparticles in MOF-801 for activating hydrogen and hydrogenation of C=C in the MOF ligand as activated hydrogen detector, a research platform is built with Pt@MOF-801 to measure the hydrogenation region for quantifying the efficiency and spatial extent of hydrogen spillover. A water-assisted hydrogen spillover path is found with lower migration energy barrier than the traditional spillover path via ligand. The synergy of the two paths explains a significant boost of hydrogen spillover in MOF-801 from imperceptible existence to spanning at least 100-nm-diameter region. Moreover, such strategy shows universality in different MOF and covalent organic framework materials for efficiency promotion of hydrogen spillover and improvement of catalytic activity and antitoxicity, opening up new horizons for catalyst design in porous crystalline materials.
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To well address the problem of low stability for Ru-based catalysts against sintering and leaching during synthesis and aqueous levulinic acid (LA) hydrogenation to γ-valerolactone ...(GVL), herein we demonstrate an “inside-to-outside” synthetic strategy for robust yolk-structured nanospheres within a single Ru nanoparticle (NP, 4.2 nm) anchored inside the mesoporous shell (pore size, 4.0 nm), denoted as YS Ru@HMCS (yolk-structured Ru encapsulated into hollow mesoporous carbon sphere). Such a shell-supported-core configuration combines the merits of conventional yolk-structured and supported types, in which the active core is not only fully exposed, but also strongly anchored on the shell, based on the optimized interaction between oxidized Ru NP and N-doped mesoporous carbon shell. As a consequence, the resultant YS Ru@HMCS, delivers a high LA conversion (99.4%), a large selectivity to GVL (99.9%), and prolonged cycling life (up to 9 cycles) under water towards the LA hydrogenation, that exceeds conventional yolk-structured and supported analogues. Sintering-resistant, a single Ru NP is successfully encapsulated, and its leaching-resistant property is enhanced based on the improved metal-support contact, thus affording a highly stable Ru catalyst. Moreover, such a synthetic concept can be extended to the stabilization of other supported catalysts, providing a general approach to enhancing both the thermal and chemical stability of supported nanocatalysts.
Metal–organic framework (MOF)-based derivatives have attracted an increasing interest in various research fields. However, most of the reported papers mainly focus on pristine MOF-based derivatives, ...and research studies on functional MOF-based derivative composites are rare. Here, a simple strategy has been reported to design functional MOF-based derivative composites by the encapsulation of metal nanoparticle (MNP) in MOF matrixes (MNP@MOF) and the high-temperature calcination of MNP@MOF composites. The as-prepared MNP@metal oxide composites with a hierarchical pore structure exhibited excellent catalytic activity and high stability for the CO oxidation reaction.
Building bridges among different types of catalysts to construct cascades is a highly worthwhile pursuit, such as chemo-, bio-, and chemo–bio cascade reactions. Cascade reactions can improve the ...reaction efficiency and selectivity while reducing steps of separation and purification, thereby promoting the development of “green chemistry”. However, compatibility issues in cascade reactions pose significant constraints on the development of this field, particularly concerning the compatibility of diverse catalyst types, reaction conditions, and reaction rates. Metal–organic framework micro/nano reactors (MOF-MNRs) are porous crystalline materials formed by the self-assembly coordination of metal sites and organic ligands, possessing a periodic network structure. Due to the uniform pore size with the capability of controlling selective transfer of substances as well as protecting active substances and the organic–inorganic parts providing reactive microenvironment, MOF-MNRs have attracted significant attention in cascade reactions in recent years. In this Perspective, we first discuss how to address compatibility issues in cascade reactions using MOF-MNRs, including structural design and synthetic strategies. Then we summarize the research progress on MOF-MNRs in various cascade reactions. Finally, we analyze the challenges facing MOF-MNRs and potential breakthrough directions and opportunities for the future.
Metal-organic frameworks(MOFs) have been widely regarded as promising carriers for enzyme immobilization owing to their advantages in improving loading and regulating interaction with enzymes. ...However, they are still suffering from the problems of slow mass transfer and compromising activity. In this paper, the active two-dimensional(2D) MOF of Cu-TCPP(Fe)TCPP=tetrakis(4-carboxy-phenyl)porphyrin, which possesses the biomimetic architecture of peroxidase, was adopted to anchor cytochrome(Cyt c) for the enhancement of catalytic activity. The atomic/nanometer thickness and micrometer lateral dimension of 2D MOFs can ensure the full exposure of immobilized enzymes and a shorter diffusion distance for the reactant molecules. Besides, the active carrier can provide synergistic catalysis and activity compensation during the reaction. When tested in the decomposition reaction of H
2
O
2
, Cyt c/Cu-TCPP(Fe) exhibited nearly twice catalytic activity and an accelerated catalytic rate compared to free Cyt c.
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