Covalent organic frameworks (COFs) are an emerging class of porous crystalline polymers with broad potential applications. So far, the availability of three-dimensional (3D) COFs is limited and more importantly only one type of covalent bond has been successful used for 3D COF materials. Here, we report a new synthetic strategy based on dual linkages that leads to 3D COFs. The obtained 3D COFs show high specific surface areas and large gas uptake capacities, which makes them the top COF material for gas uptake. Furthermore, we demonstrate that the new 3D COFs comprise both acidic and basic sites, and act as excellent bifunctional catalysts for one-pot cascade reactions. The new synthetic strategy provides not only a general and versatile approach to synthesize 3D COFs with sophisticated structures but also expands the potential applications of this promising class of porous materials.

Rhenium(I)-carbonyl-diimine complexes have emerged as promising photocatalysts for carbon dioxide reduction with covalent organic frameworks recognized as perfect sensitizers and scaffold support. Such Re complexes/covalent organic frameworks hybrid catalysts have demonstrated high carbon dioxide reduction activities but with strong excitation energy-dependence. In this paper, we rationalize this behavior by the excitation energy-dependent pathways of internal photo-induced charge transfer studied via transient optical spectroscopies and time-dependent density-functional theory calculation. Under band-edge excitation, the excited electrons are quickly injected from covalent organic frameworks moiety into catalytic RheniumI center within picosecond but followed by fast backward geminate recombination. While under excitation with high-energy photon, the injected electrons are located at high-energy levels in RheniumI centers with longer lifetime. Besides those injected electrons to RheniumI center, there still remain some long-lived electrons in covalent organic frameworks moiety which is transferred back from RheniumI. This facilitates the two-electron reaction of carbon dioxide conversion to carbon monoxide.

The unique sandwiched structure and favorable crystallization kinetics have endowed two-dimensional (2D) halide perovskites with excellent ambient stability and facile film formation compared to their three-dimensional counterparts. However, the heterogeneous...

Metal–organic frameworks (MOFs) as a class of crystalline porous solids have attracted considerable attention due to their promising potential performance.