Finely Controlled Stepwise Engineering of Pore Environments and Mechanistic Elucidation of Water-Stable, Flexible 2D Porous Coordination Polymers.

Two porous coordination polymers (PCPs) with different topologies (NTU-19: sql and NTU-20: dia) underwent finely controlled, stepwise crystal conversions to yield a common water-stable, flexible 2D framework (NTU-22: kgm). The crystal conversions occurred directly at higher temperature via the 3D intermediate (NTU-21: nbo), which could be observed at lower temperature. The successful isolation of the intermediate product of NTU-21, characterization with in situ PXRD and UV/Vis spectra were combined with DFT calculations to allow an understanding of the dynamic processes at the atomic level. Remarkably, breakthrough experiments demonstrate NTU-22 with integral structural properties allowed significant CO2 /CH4 mixture separation.

Chemically Robust, Cu-based Porous Coordination Polymer Nanosheets for Efficient Hydrogen Evolution: Experimental and Theoretical Studies.

Due to the extremely high number of accessible active sites and short diffusion path, porous coordination polymer (PCP) nanosheets have demonstrated a variety of promising applications, especially for energy conversion and mass transfer. However, the development of chemically stable PCP nanosheets with dense active sites and large lateral size is a great challenge in terms of feasible considerations. Herein, we first designed and prepared a kind of chemically stable PCP nanosheets via a bottom-up and a top-down integral strategy. Featuring densely exposed and periodic Cu2+ active sites (2.1 × 106 per µm2), as well as ultrathin nature (5 nm) and significant pores (18 Å), this nanosheet demonstrated remarkable performance of electrocatalytic hydrogen evolution. Furthermore, one plausible process and the effect of Cu2+ active sites were proposed and validated by density functional theory calculations.

Mechanical Synthesis of COF Nanosheet Cluster and Its Mixed Matrix Membrane for Efficient CO2 Removal.

Covalent organic framework (COF) membranes used for selective removal of CO2 were believed as an efficient and low-cost solution to energy and environmental sustainability. In this study, the amide modified COF nanosheet cluster with a 2D structure was facilely prepared through solid reaction, exhibiting good adsorption-based CO2 selectivity (223 at 273 K and 90 at 298 K) toward N2. Remarkably, the mixed matrix membrane (MMM) that consists of a lesser amount of COF filler (1 wt %) shows promising CO2/N2 gas selectivity (∼64). In addition, the competitive adsorption prompts the selectivity to ∼72 under an equimolar CO2/N2 mixture, which surpasses the values of all reported COF membranes. It is worth to note that the binary gas separation is stable during 120 h.