Sol-gel processing of a covalent organic framework for the generation of hierarchically porous monolithic adsorbents

•COFs are shown to be frequently unstable in-plane mechanical shear•A method of COF monolith formation that enables hierarchical porosity is presented•Hierarchical mesopores enable improved gas uptake and selectivity•Hierarchical can accurately modeled via lattice-gas methods Porous materials used industrially as macroscopic pellets exhibiting interstitial space porosity. Although conventional pelletization suitable for mechanically robust materials, similar processing result in sharp losses capacity state-of-the-art adsorbent a their inherently lower degrees stability. Here, we show COFs synthesized date shear further present simple, rapid, general process the preparation centimeter-scale, hierarchically porous, monolithic COFs. monoliths thus prepared exhibit system intercrystallite mesopores, which push final gas-uptake capacities levels above those powder or single-crystal analogs same material. These characteristics, without any chemical modification, both mixed-gas selectivity target gases within relevant gaseous compositions. Covalent organic frameworks (COFs) have emerged versatile material platform such applications separations, reaction engineering, energy storage. Their low stability, however, renders existing ineffective, contributing pore collapse, blockage, insufficient densification crystallites. shaping densifying into centimeter-scale porous need templates, additives, binders. This minimizes damage from shear-induced plastic deformation provides network interparticle exploit accessing analyte achievable intrinsic structure. Using model, capture structure across mesoporous range tie architecture performance gas-storage -separation applications. Collectively, these results represent substantial step practical applicability other weak materials. capable reducing cost intensity industrial processes critically needed transitioning carbon-neutral cycle.1Sholl D.S. 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Non-negative matrix factorization PDF-XRD data three independent components attribute non-crystalline-layer content, residual starting-material multilayer crystalline) content: A, B, C, respectively 3G). methanol-activated fraction 0.75, respective C increased, indicating gradually improves damage. Above sharply declines, resulting increased content TPB-DMTP-COF, seen increasing weighting component activation, recovered—an observation findings studies providing clear evidence correlation between observable noted powdered systems.8Sick understand mechanism crystallite non-crystalline layers monoliths, high-resolution transmission (HR-TEM) NanoBlitz indentation sufficiently disrupted 4). few indicated series small domains bridged less-ordered regions. Fourier transforms image 4C, inset) features diffuse band corresponding real-space 0.36 nm—consistent spacing values analysis (0.37 nm) (0.35 data. crystalline-to-turbostratic-disordering mechanism, milled graphite, might responsible monoliths. At level, mapping heterogeneities modulus hardness 200 × ?m region triggered action, differences local give rise regions lesser disruption, slightly differing pellet. non-porous After establishing conditions explicitly damage, mercury porosimetry small-angle scattering (SAXS) free-volume mesoscale. Pore-size distributions intrusion curves scCO2-activated mesoporosity 18.7 attributable narrow 3A, inset). Broader macroporosity centered width around observed. By contrast, non-monolithic Xu al. 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