Herein, the advances in low-dimensional core-shell EM wave absorption materials are outlined and a selection of the most remarkable examples is discussed. The derived key information regarding dimensional design, structural engineering, performance, and structure-function relationship are comprehensively summarized. Moreover, the investigation of the cuttingedge mechanisms is given particular attention. Additional applications, such as oxidation resistance and self-cleaning functions, are also introduced. Finally, insight into what may be expected from this rapidly expanding field and future challenges are presented.

Recovery and purification of ionic liquids from solutions.

Carbon dots (CDs) with red-emitting room-temperature phosphorescence (RTP) are rarely reported because of the increasing nonradiative decay of the excited states and the decreasing energy gap between the excited states and ground states. Herein, we demonstrate a facile strategy for modulating the RTP properties of CDs in terms of donor–acceptor energy transfer (EnT) in the CDs-in-zeolite system. Upon tuning of the heteroatoms (Zn 2+ , Mn 2+ ) doped in the aluminophosphate zeolite frameworks, CDs@zeolite composites with green and red phosphorescence have been prepared via in situ hydrothermal synthesis. In such composites, the zeolite matrix provides an efficient confinement role in stabilizing the triplet states of CDs. Significantly, the Mn-doped zeolite could act as an energy acceptor allowing EnT from excitons of CDs to the dopant in the host matrix, generating the intriguing red RTP behavior. This work provides an effective strategy for developing CD-based composite materials with special RTP emissions as well as new fields for applications.

Covalent organic frameworks (COFs) are one family of crystalline porous polymers constructed from organic building blocks through covalent linkages. [11] They exist as 2D or 3D structures with high order and periodicity. 2D COFs, in particular, possess remarkable potential as membrane materials due to the intrinsic in-plane porosity, short transport channels, tunable functionality, as well as excellent hydrothermal stability. [12] The presence of ordered in-plane pores in 2D COFs is highly distinct from other 2D materials such as graphene oxide (GO), which rely instead on interlamellar transport or deliberate introduction of in-plane defects to generate transport pathways. [13] The inplane pores of 2D COFs provide short gas transport pathways and thus avoid the long zigzag transport pathways in nonporous 2D material membranes, affording high gas permeability in COF membranes. We have investigated COF membranes for gas separations among other research groups, revealing their highly competitive performance. [14] However, the relatively large pore size (>6 Å) of most COFs remains a major stumbling block when fabricating COF membranes for separating small gas molecules (<4 Å). [14a] One approach to overcome this limitation is to narrow the pore size by introducing functional groups onto the COF walls through an in situ synthesis or post-modification. [15] Another way is to construct multilayer MOF/COF or COF/COF membranes by forming narrowed apertures or synergistic effects at the interface between different layers. Those membranes have shown significantly enhanced separation performance compared with their corresponding single-phase membranes. [14b,16] From our developmental experience, we have made several observations: 1) the relatively large membrane thickness (greater than 1 µm) limits the separation performance, especially the gas permeance, 2) the stacking mode needs to be better optimized to maximize the separation capability, and 3) the complex, long preparation processes limit the wide application and scaling-up preparation of the membranes. Should ultrathin nature, appropriate aperture size, facile membrane preparation process, and excellent stability be realized simultaneously, the resultant membranes will be expected to show benchmark molecular sieving performance.Herein, we propose a multi-interfacial engineering strategy to prepare high-performance COF-based membranes for small-molecule gas separations. Specifically, we combined two COFs (TpPa-SO 3 H and TpTG Cl ) with different pore sizes Covalent organic frameworks (COFs) are promising membrane materials due to their high porosity, ordered arrangements, and high stability. However, the relatively large pore size and complicated membrane preparation processes of COFs limit their applications in sieving small gas molecules, even at a lab scale. Herein, a multi-interfacial engineering strategy is proposed, that is, direct layer-by-layer interfacial reaction of two COFs (TpPa-SO 3 H and TpTG Cl ) with different pore sizes to form narrowed apertures at ...