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A new porous liquid system based on the coalition of MOPs and bulky IL was designed. The liquid materials exhibit permanent cavities, long-term durability, and good ability to separate CO2 from N2 and CH4 not only as an entity but also as a membrane.

After UV illumination at 254 nm for 10 min, the incorporated LiYGeO4:Bi3+ in the PCN-PLM can continuously provide light irradiation at 365 nm to regulate the CO2 adsorption capacity of PCN-250.

Reproducing the highly efficient catalytic cascade system to mimic life behaviors in vitro has been intensively investigated over the past few decades. However, except for biocatalysis with enzymes, most chemocatalytic cascades in essence combine several reactions that occur over mutually independent catalytic sites in a container. Herein, with a series of control experiments and stepwise theoretical derivation based on the calculations of density functional theory and a semi-empirical method, a generalized cascade catalysis is discovered for the chemocatalytic conversion of CO2 to higher alcohols over a porphyrinic zirconium metal–organic framework, PCN-224-Cu. Two types of catalytic sites in PCN-224-Cu, i.e., the Zr6 cluster and TCPP-Cu unit, act like organelles, which can complete a class of reactions instead of particular one. The Zr6 cluster is in charge of molecular dissociation, while the TCPP-Cu unit is responsible for molecular assembly. Therefore, semi-finished intermediates repeatedly transfer between the two types of catalytic sites until the ultimate formation of ethanol with high efficiency (ethanol yield, 4.53 mmol h−1 gcat.−1 at 403 K) and selectivity (∼100%).

The empiricism that extrinsic or doped materials universally perform much better than their intrinsic counterparts has been verified to be feasible in the adsorptive CO2 capture. Thus, a variety of N-doped solid adsorbents are well-engineered to adsorb CO2. However, the true nature of the N-doped sites in the aggregation state and the underlying mechanism of CO2 adsorption therein are difficult to determine. In the present study, four well-defined azacyclo copolymers with peculiar textural characteristics, uniformly arrays and tunably effective N-doped sites were fabricated to experimentally determine the precise relation between adsorbed CO2 molecules and the N-doped sites incorporated into an adsorbent. With multifaceted quantum chemical computations, induction forces were proven to account for the improved CO2 adsorption on the N-doped sites instead of the conventionally assumed generalized acid–base interaction. The negative electrostatic potentials were demonstrated to be the real cause for improving the CO2 adsorption and a robust indicator for the effectiveness of the N-doped sites. Besides, a precise linear function is proposed to quantitatively describe this subject–object relationship for the first time.

Nanoporous adsorbents are highly efficient in selectively capturing aromatic sulfur compounds such as thiophene, benzothiophene, dibenzothiophene, and 4,6-dimethyldibenzothiophene that are refractory to remove by traditional techniques from liquid hydrocarbon fuels. In the past decades, great progress has been made in design and fabrication of nanoporous adsorbents as well as the judicious strategies of promoting their performance for deep desulfurization. However to the best of our knowledge, a comprehensive review from this perspective has never been reported until now. Therefore, a review summarizing these nanoporous adsorbents and advanced strategies is highly anticipated. In this review, we provide an overview of the synthesis methods, improvement strategies, and prospective of the nanoporous adsorbents for applications with adsorptive desulfurization. The concerned materials cover most of the traditional and recently emerged nanoporous materials, and are introduced and basically grouped by material type. Each category is illustrated with some typical examples, and the fundamental principles on how to design and fabricate nanoporous adsorbents are highlighted. The adsorption mechanism is discussed in detail as well.

Cu(I)-containing materials have great potential in various applications such as in CO adsorption; however, development of an efficient and controllable method to produce Cu(I) sites remains a significant challenge; herein, a two-step double-solvent (DS) strategy is reported for the first time to fabricate Cu(I) sites in a representative metal–organic framework, MIL-101(Cr); this strategy ensures that both introduction of the Cu(II) precursor and its reduction to Cu(I) occur inside the pores and significantly minimizes the aggregation of Cu species. This is difficult to realize through conventional methods used for Cu(II) introduction (wet impregnation) or reduction (liquid-phase reduction). The two-step DS strategy involves selective reduction of Cu(II) to form Cu(I) without the formation of any Cu(0). The obtained Cu(I)-containing materials exhibit an excellent CO adsorption capacity (up to 2.42 mmol g−1) at 298 K and 1 bar, much better than that of the benchmark adsorbents including CuCl/γ-Al2O3 (1.0 mmol g−1), CuCl/MCM-41 (0.57 mmol g−1), and CuZSM-5 (0.11 mmol g−1).

Poor dispersity and low stability are two predominant shortcomings hindering the applications of metal–organic polyhedra (MOPs). The confinement of MOPs in nanoscale cavities of mesoporous matrices is efficient in overcoming both shortcomings, while the improvement of the current double-solvent method is highly expected. Here we develop a facile, controllable strategy to fabricate three MOPs (coordinated from dicopper and carboxylates) in confined cavities via in situ site-induced assembly (SIA), for the first time. The cavities of mesoporous matrix SBA-16 were pre-functionalized with amine sites, which induce in situ assembly of precursors that diffused into cavities. Hence, both the amount and location of MOPs in the mesoporous matrix can be easily controlled. Upon confinement, the dispersity, stability, and catalytic performance (on ring-opening reactions) of MOPs are greatly improved. Moreover, the enhancement of stability makes it possible to observe MOPs using high-resolution transmission electron microscopy (HRTEM) directly.

Owing to their high physicochemical stability, low skeletal density, tailorable surface properties, and high porosity, microporous crosslink polymers are highly promising for selective CO2 capture, separation, and storage. The crosslinking (CL) and crosslinker length (CLL) in a polymer play a quite significant role in enhancing selective CO2 capture. To investigate the role of CL and CLL, polymers with no crosslinking (non-crosslinking, NCL), and small-(SCL), and long-crosslinker lengths (LCL) were successfully fabricated. It is noteworthy that the polymer containing SCL has remarkable CO2 adsorption capacity and selectivity over the polymer with LCL and NCL. High selectivity for CO2 over CH4/N2 was observed in the sequence SCL > LCL > NCL. This indicates that not only CL but CLL is also significantly important in generating highly efficient adsorbents. The adsorption capacity reaches 208.3 mg g−1, which is higher than that of the benchmarks including activated carbon (122.8 mg g−1), and 13X zeolite (180.3 mg g−1), as well as most reported carbon-based adsorbents. The CO2/N2 and CO2/CH4 selectivity reaches 541.4 and 64, respectively. Moreover, excellent recyclability was observed without loss in CO2 adsorption for 10 cycles. Thus, high CO2 capture, excellent selectivity, and high recyclability under energy-saving mild regeneration conditions make microporous polymers a unique adsorbent for selective CO2 capture from flue gas and natural gas.

Due to their synthetic diversification, low skeletal density, and high physicochemical stability, porous polymer networks (PPNs) are highly promising in a variety of applications such as carbon capture. Nevertheless, complicated monomers and/or expensive catalysts are normally utilized for their synthesis, which makes the process tedious, costly, and hard to scale up. In this study, a facile nucleophilic substitution reaction was designed to fabricate PPNs from low-cost monomers, namely chloromethyl benzene and ethylene diamine. A surfactant template was also used to direct the assembly, leading to the formation of PPN with enhanced porosity. It is fascinating that the polymerization reactions can occur at the low temperature of 63 °C in the absence of any catalyst. The obtained PPNs contain abundant secondary amines, which offer appropriate adsorbate–adsorbent interactions from the viewpoints of selective CO2 capture and energy-efficient regeneration of the adsorbents. Hence, these PPNs are highly active in selective adsorption of CO2, and unusually high CO2/N2 and CO2/CH4 selectivity was obtained. Moreover, the PPN adsorbents can be completely regenerated under mild conditions.

Due to their versatility, nontoxicity, and low cost, Cu(I) ion exchanged zeolites are of great interest for various applications. Despite many attempts, the development of an efficient, controllable, and energy-saving approach to fabricate Cu(I) sites in zeolites remains an open question. In this study, a strategy was developed to convert Cu(II) in zeolites to Cu(I) selectively using vapor-induced reduction (VIR) with methanol. The methanol vapors generated at elevated temperatures diffuse into the pores of zeolites and interact with Cu(II) ions, leading to the formation of Cu(I). This strategy allows the construction of Cu(I) sites at low temperatures and avoids the formation of Cu(0). Moreover, the obtained material exhibits excellent performance in the adsorptive separation of propylene/propane with regard to both capacity and selectivity, which is obviously superior to the material prepared by the conventional autoreduction method as well as using various typical adsorbents.

Metal–organic frameworks (MOFs) have attracted extensive attention due to their large surface area, diverse structures, and tuneable functionality. However, the poor hydrostability of most reported MOFs hinders their practical applications severely. In this paper, we report a strategy to modulate the properties of a typical MOF, namely MOF-5 [Zn4O(BDC)3; BDC = 1,4-benzenedicarboxylate] by hybridizing it with a natural clay (i.e. attapulgite), for the first time. A new kind of hybrid material resulting from the hybridization of the MOF and attapulgite was thus constructed. Our results showed that the hydrostability of the MOF was apparently improved due to the hybridization with attapulgite. The frameworks of MOF-5 were degraded seriously under the humid atmosphere, while the structure of the hybrid materials could be well preserved. We also demonstrated that the hybrid materials were highly active in the heterogeneous Friedel–Crafts alkylation reaction of benzyl bromide with toluene. The conversion of benzyl bromide reached ∼100% under the reaction conditions investigated. More importantly, the catalytic stability of the hybrid materials was significantly enhanced owing to the introduction of attapulgite. The activity could be well recovered with no detectable loss, and the conversion remained at ∼100% at the sixth run, which was apparently higher than that of MOF-5 (27.7% at the sixth run). The excellent hydrostability, catalytic activity, and reusability make the present materials highly promising for utilization as heterogeneous catalysts in practical applications.

Deep desulfurization of transportation fuels via π-complexation adsorption is an effective method for the selective capture of aromatic sulfur compounds. Taking into consideration that the desulfurization of transportation fuels proceeds in the liquid phase, separation and recycling of adsorbents should be greatly facilitated if the adsorbents were endowed with magnetism. In this paper, magnetically responsive core–shell π-complexation adsorbent microspheres, AgNO3/Fe3O4@mSiO2 (mSiO2 denotes mesoporous silica), which comprises a core of magnetite particles and a shell of mesoporous silica dispersed with AgNO3, was developed for the first time. The silica shell exhibits highly open mesopores with perpendicularly aligned pore channels, large surface area (694 m2 g−1) and uniform pore size (2.3 nm), which is quite beneficial to the accommodation of Ag(I) active species. As a result, AgNO3 can be well dispersed in the pores of silica shells and are highly accessible to adsorbate molecules. Our results show that the adsorbent is active in the adsorptive removal of a typical aromatic sulfur compound, thiophene, via π-complexation under ambient conditions. More importantly, the superparamagnetism allows the adsorbent to be separated conveniently from the adsorption system in several seconds by the use of an external field. After desulfurization, the adsorbents were regenerated by washing with isooctane and subsequent thermal dispersion in Ar. The regenerated adsorbent after six cycles still shows a good adsorption capacity (0.145 mmol g−1 or 4.64 mg g−1), which is comparable to the fresh adsorbent (0.147 mmol g−1 or 4.70 mg g−1). The magnetically responsive π-complexation adsorbent may be a promising candidate for the deep purification of transportation fuels.