Yangyang Guo

The simultaneous capture of carbon dioxide (CO2) and carbon monoxide (CO) from complex industrial gases represents a critical challenge. Designing framework sorbents that combine selective molecular recognition with stability is essential. Herein, a series of anthracene-based metal–organic frameworks (MOFs), M-ABHBs (M = Co, Mg, Mn, and Ni), were successfully synthesized. By regulating metal centers, which leads to different interactions between gases (CO2/CO/N2) and metal–ligand pairs in the framework, excellent CO adsorption selectivity has been discovered. Notably, Mg/Mn-ABHBs allow efficient binary CO2/N2 separation, and Co/Ni-ABHBs enable benchmark ternary CO2/CO/N2 separation by increasing the adsorption affinity toward CO. This unique phenomenon is rare among adsorbents. Such behaviors enable a stepwise separation strategy to selectively capture CO2 and CO from ternary mixtures. Co-ABHB exhibits high selectivity of CO/N2 (13.1), while Mg-ABHB shows high selectivity of CO2/N2 (66.6) and CO2/CO (5.8). In situ DRIFTS and theoretical calculations indicate that the former is the result of the strong interactions of Co-CO in the cavities of Co-ABHB, while Mg sites strongly capture only CO2, not CO. Breakthrough tests show that from a CO2/CO/N2 mixture, M-ABHBs demonstrated excellent separation performance. This work offers a design strategy for efficient carbon capture under complex industrial gas conditions.

Adsorption of CO2 from blast furnace gas (BFG) faces competitive adsorption of H2O and poisoning by H2S. Suppression of H2O and a small amount of H2S adsorption preserving CO2 adsorption, was required for zeolite-based pressure swing adsorption (PSA) technology. The zeolite-based composite was explored for CO2 adsorption, which was fabricated by Y zeolite functionalized with short-chain (MTCS) and long-chain (BTS) silanes. Under static CO2 adsorption conditions, CO2 absorption capacity of Y, MTCS-Y, and BTS-Y were 100.39, 100.81, and 104.23 cm3·g–1, respectively, and H2O adsorption of silanized zeolite was reduced. Multicomponent competitive adsorption (CO2/H2O/H2S) showed that the H2O and H2S breakthrough times of zeolite-modified long-chain silane were greatly shortened, suggesting better hydrophobicity and inhibiting H2S adsorption. After H2S exposure, in comparison to Y zeolite, the total sulfur deposition on MTCS-Y and BTS-Y declined by 48.75% and 71.25%, respectively. MTCS-Y showed excellent hydrophobic stability and sulfur resistance, as evidenced by the preservation of its surface contact angle and the retention of 96.5% of its original CO2 adsorption capacity. Electrostatic potential calculation (ESP), in situ FTIR, and breakthrough experiments revealed that H2O and H2S adsorption of silanized zeolite was inhibited by the Y hydrophobic layer physical blocking and interface polarity adjustment. Silanized Y zeolites significantly inhibited the adsorption of H2O and H2S for CO2 adsorption in BFG conditions.

This review summarized recent advances in direct air capture (DAC), including the chemistry foundation, materials and processes, offering insights into the development of the next generation DAC systems to achieve Net Zero targets.

Global warming and the utilization of greenhouse gases have become a matter of worldwide concern. Porous adsorbents have emerged as core materials for effectively capturing CO ₂ and its isotopes. Flexible metal–organic frameworks (MOFs) stand out from traditional rigid adsorbents due to their unique structural flexibility and dynamic behavior. Owing to these characteristics, flexible MOFs have emerged as highly promising materials for CO ₂ adsorption and separation. Moreover, the high working capacity and excellent selectivity of flexible MOFs confer significant advantages for CO ₂ capture applications. They are expected to reduce energy consumption during adsorption–desorption cycles, positioning them as a promising new adsorbent. This review offers an overview of the dynamic behaviors of CO ₂ adsorption by flexible MOFs. Furthermore, we summarized the cutting-edge achievements in adjusting gating pressure, adsorption hysteresis loops, and CO ₂ affinity through ligand engineering, regulating the metal node, and functionalizing the pore environment. The challenges encountered with the material during actual carbon capture were discussed. Finally, an in-depth prospect is provided to promote the application of these materials in low-carbon energy and the high-value utilization of CO ₂ and its isotopes.

Nitrogen trifluoride (NF3) and carbon tetrafluoride (CF4) are critical gases in the semiconductor industry. However, their current lack of effective recycling and separation results in significant waste emissions, which are not only costly but also pose significant environmental challenges. Their separation remains a critical challenge due to their nearly identical physicochemical properties (Δbp <1°C, similar polarizability). Here, we demonstrate that a zinc-based metal-organic framework (CALF-20) with precisely tuned 4.8 Å pores achieves exceptional NF3/CF4 separation through molecular sieving. At 298 K, this material exhibits a record-high NF3/CF4 absorption ratio of 41.1, and a CF4 purity of 99.5% can be achieved through breakthrough experiments. Structural characterization and computational studies reveal that the unique pore channel properties preferentially adsorb NF3 (kinetic diameter: 4.5 Å) while effectively excluding CF4 (4.8 Å). This advance enables cost-effective gas purification at $12.3 per kilogram, providing a practical solution for sustainable semiconductor manufacturing.