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Abstract Graphene oxide (GO) membranes have shown great potential in ionic sieving from aqueous solutions. However, it remains challenging for GO membranes to exclude small ions with a large water flux. Herein, organic ions are confined onto the GO interlaminations to form a precisely restricted 2D channel size of 0.71 nm, which presents >99.9% NaCl rejections and high freshwater fluxes via the pervaporation method, both being orders of magnitude higher than that of common GO membranes. Theoretical calculations reveal that, apart from controlling the 2D channel size of GO by strong cation–/anion–π and π–π interactions, the organic ions act as vapor traps to remarkably shorten vapor diffusion distance and then as water pumps to significantly enlarge water permeability. It not only theoretically explains the low permeability over the common GO membranes with large 2D channels, but also experimentally demonstrates fast and complete desalination on the organic ions-GO membrane.

Abstract The electrochemical carbon dioxide reduction reaction (CO2RR) for high‐value‐added products is a promising strategy to tackle excessive CO2 emissions. However, the activity of and selectivity for catalysts for CO2RR still need to be improved because of the competing reaction (hydrogen evolution reaction). In this study, for the first time, we have demonstrated dual atomic catalytic sites for CO2RR from a core–shell hybrid of the covalent–organic framework and the metal–organic framework. Due to abundant dual atomic sites (with CoN4O and ZnN4 of 2.47 and 11.05 wt.%, respectively) on hollow carbon, the catalyst promoted catalysis of CO2RR, with the highest Faradic efficiency for CO of 92.6% at –0.8 V and a turnover frequency value of 1370.24 h–1 at –1.0 V. More importantly, the activity and selectivity of the catalyst were well retained for 30 h. The theoretical calculation further revealed that CoN4O was the main site for CO2RR, and the activity of and selectivity for Zn sites were also improved because of the synergetic roles.

Platinum (Pt)‐based catalysts are considered as the most active catalysts for the oxygen reduction reaction (ORR). However, their applications have remained limited because of the high cost of Pt, and developing catalysts with low Pt contents is a challenge. Herein, a highly active catalyst (Pt–COF800) is constructed for the ORR by immobilizing hierarchical Pt subnano‐ and nanoparticles on covalent organic framework (COF)‐derived carbon. The catalyst shows excellent activity in alkaline conditions. The physical characterization demonstrates low nuclear Pt atoms and nanoparticles and confirms the role of heterogeneous active sites. This work paves the way for the construction of functional porous carbon materials with dual‐scale Pt clusters and may be applied to industrial catalytic reactions.

Abstract Metal–organic frameworks and covalent organic frameworks have been widely employed in electrochemical catalysis owing to their designable skeletons, controllable porosities, and well‐defined catalytic centers. However, the poor chemical stability and low electron conductivity limited their activity, and single‐functional sites in these frameworks hindered them to show multifunctional roles in catalytic systems. Herein, we have constructed novel metal organic polymers (Co‐HAT‐CN and Ni‐HAT‐CN) with dual catalytic centers (metal–N4 and metal–N2) to catalyze oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). By using different metal centers, the catalytic activity and selectivity were well‐tuned. Among them, Co‐HAT‐CN catalyzed the ORR in a 4e− pathway, with a half‐wave potential of 0.8 V versus RHE, while the Ni‐HAT‐CN catalyze ORR in a 2e− pathway with H2O2 selectivity over 90%. Moreover, the Co‐HAT‐CN delivered an overpotential of 350 mV at 10 mA cm−2 with a corresponding Tafel slope of 24 mV dec−1 for OER in a 1.0 M KOH aqueous solution. The experimental results revealed that the activities toward ORR were due to the M–N4 sites in the frameworks, and both M–N4 and M–N2 sites contributed to the OER. This work gives us a new platform to construct bifunctional catalysts.