Ultrathin Metal–Organic Framework Nanosheets Exhibiting Exceptional Catalytic Activity

Abstract

Two-dimensional (2D) metal–organic framework nanosheets (MONs) or membranes are classes of periodic, crystalline polymeric materials that may show unprecedented physicochemical properties due to their modular structures, high surface areas, and high aspect ratios. Yet preparing 2D MONs from multiple components and two different types of polymerization reaction remains challenging and less explored. Here, we report the synthesis of MOF films via interfacial polymerization, which involves three active monomers for simultaneous polycondensation and polycoordination taking place in a confined interface. The well-defined lamellar structure of the MOF films allowed feasible and scalable exfoliation to produce free-standing 2D MONs with high aspect ratio up to 2000:1 and ultrathin thickness (∼1.7 nm). The pore structure was revealed by high-resolution TEM images with near-atomic precision. The imide-linkage of MONs provided superior thermal (up to 530 °C) and good chemical stability in the pH range from 3 to 12. More importantly, the MONs exhibited exceptional catalytic activity and superior reusability for the hydroboration reactions of alkynes, in which the turnover frequency (TOF) reached 41734 h–1, which is 2–4 orders of magnitude greater than that reported for homogeneous and heterogeneous catalysts.

A copper nitride nanocube catalyst for highly efficient hydroboration of alkynes

“…Based on the co-existence of the Lewis acid and base sites on Cu 3 N NCs, a reaction mechanism is proposed in Scheme 5. 7,8 First, EtOH is adsorbed and activated on the surface of sites of Cu 3 N NCs (step 1). Then the activated EtOH reacts with B 2 Pin 2 to form a Cu–BPin species, along with the production of EtO–BPin (step 2).…”

“…7 To overcome these drawbacks, some efforts have been devoted to developing heterogeneous Cu catalysts, such as CuO/MgO, Cu metal–organic frameworks (Cu-MOF), and Cu nanospheres/graphene nanosheets (Cu-NPs/rGO) (Scheme 1B). 8 However, these catalytic systems require the use of additives to activate B 2 Pin 2 . Recently, Li's group carried out a remarkable research study using single-atom Cu catalysts for the hydroboration of alkynes under additive-free conditions.…”

A rational design of functional porous frameworks for electrocatalytic CO2reduction reaction

“…Specifically, the tandem electrolyzers achieved an n-propanol FE of 15.9% together with the corresponding halfcell power conversion efficiency (CPE) of 19.3%. Hence, tandem With the development of Cu-based functional porous frameworks, an increasing number of unique linking types and active site configurations has been designed and obtained, which are suitable equally for the ECO 2 RR, such as Cu-based MOFs formed by Cu 3 clusters and imide linkers (Li et al 143 and Lan et al 144 ), bicentric Cu-porphyrin structure (Peng et al 145 ), metal-porphyrin linked mercurated graphynes (Wong et al 146 ), and Cu-P 3 sites with novel coordinated heteroatom species and a high single-atom density of 11.3 wt% (Wang et al 147 ), which provide abundant Cu-based catalysts with reference significance on adjustable active sites for an improved ECO 2 RR performance.…”

Molecular Engineering of Metal–Organic Layers for Sustainable Tandem and Synergistic Photocatalysis

“…Despite their great potential for sustainable catalysis, the difficulty in MOL synthesis and characterization presents a significant bottleneck for the further development of MOL catalysts. To date, only Hf 6 and H 12 SBUs have been combined with a limited number of bridging ligands to construct MOLs. ,, Although several 2D MOFs based on Zn, Cu, and Al SBUs have been reported, − they lack stability or cannot be postsynthetically modified for catalytic applications. In recent work, a porphyrinic Hf 12 -MOL was successfully synthesized by screening a library of monocarboxylate modulators .…”