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High-capacity adsorption and removal of complex volatile organic compounds (VOCs) from real-world environments is a tough challenge for researchers. Herein, a swellable array adsorption strategy was proposed to realize the synergistic adsorption of toluene and formaldehyde on the flexible double hypercross-linked polymers (FD-HCPs). FD-HCPs exhibited multiple adsorption sites awarded by a hydrophobic benzene ring/pyrrole ring and a hydrophilic hydroxyl structural unit. The array benzene ring, hydroxyl, and pyrrole N sites in FD-HCPs effectively captured toluene and formaldehyde molecules through π-π conjugation and electrostatic interaction and weakened their mutual competitive adsorption. Interestingly, the strong binding force of toluene molecules to the skeleton deformed the pore structure of FD-HCPs and generated new adsorption microenvironments for the other adsorbate. This behavior significantly improved the adsorption capacity of FD-HCPs for toluene and formaldehyde by 20% under multiple VOCs. Moreover, the pyrrole group in FD-HCPs greatly hindered H 2 O molecule diffusion in the pore, thus efficiently weakening the competitive adsorption of H 2 O toward VOCs. These fascinating properties enabled FD-HCPs to achieve synergistic adsorption for multicomponent VOC vapor under a highly humid environment and overcame single-species VOC adsorption properties on state-of-the-art porous adsorbents. This work provides the practical feasibility of synergistic adsorption to remove complex VOCs in real-world environments.

[Display omitted] • HKUST-1 was grown on Cu-nanofiber to construct thermal-conductive HKUST-1@Cu-NF. • Self-transformation formed abundant thermal conductive adsorption sites in HKUST-1@Cu-NF. • Unsaturated Cu and microporous interface improved toluene adsorption compared to HKUST-1. • Thermal conductivity promoted heat transfer of HK@Cu-NF about >3 times than HKUST-1. • Adsorption and desorption rates of HK@Cu-NF were synchronously boosted ∼5–7 times. A major challenge in utilizing metal–organic frameworks (MOFs) for volatile organic compound (VOC) capture was their inclination for strong adsorption, which consequently impeded desorption and elevated energy demand. To overcome this challenge, the construction of HKUST-1@Cu nanofibers (HK@Cu-NF) with thermal conductive adsorption sites was proposed to synchronous enhance toluene adsorption and desorption efficiency for VOCs capture. In this work, Cu-based HKUST-1 was designed to grow on Cu nanofibers, and formed uniform coverage MOF layer with tight connection via homologous Cu self-transformation growth strategy. The synthesized composite was proved to maintain high surface area (1473 m2/g) and generate abundant unsaturated Cu sites on its nanointerface based from the thermally conductive Cu nanofibers. This unique connection structure endowed these adsorption sites with high affinity towards toluene and high thermal conductivity as well, and finally formed thermal conductive adsorption sites. As a result, HK@Cu-NF composite (80 % loading of HKUST-1) exhibited 1.9 times higher of toluene adsorption capacity at P / P 0 = 0.002 and >3 times higher of thermal diffusivity than pure HKUST-1. Furthermore, it achieved enhancement in both adsorption and desorption efficiency for toluene, which reached 4.8 and 6.9 times of pure HKUST-1. Therefore, construction of thermal conductive adsorption sites successfully improved the adsorption efficiency and regeneration efficiency for VOCs capture, and realized the low energy VOCs desorption process. [ABSTRACT FROM AUTHOR]

[Display omitted] • DABA with di-amino was introduced into MOF to construct duel-positive charge centers. • Dual-positive charge centers in MOF enhanced electrostatic interaction with toluene. • Amino in DABA formed weak affinity to H 2 O and then shielded H 2 O entry into Cr clusters in MIL. • D-MIL-101 showed high toluene uptake up to 4.69 mmol/g (3.1 times of MIL-101) at 500 ppm. • D-MIL-101 exhibited 3.3 times higher toluene work capacity than MIL-101 under 80% RH. Highly efficient capture of volatile organic compounds (VOCs) under humid conditions is a significant yet formidable task for metal–organic frameworks (MOFs). Based on the material simulation technique, we proposed implanting a significantly positive-density ligand (DABA) to modify MIL-101 and constructing dual positive-charging centers to improve MIL-101 competitive adsorption of benzene VOCs over H 2 O vapors both thermodynamically and kinetically. The introduction of DABA containing two –NH 2 groups with electrostatically positive charges into MIL-101 resulted in the formation of an open tetrahedral cage with a dual positive charging center. This facilitated strong N-H...π interactions with toluene molecules, leading them to accumulate firmly in MOF pores, and thus dramatically enhanced its adsorption capacity from 17 to 31 toluene molecules per unit cell compared to pristine MIL-101. Moreover, the open tetrahedral cage in D-MIL-101 preferentially captured toluene and occupied the strongest adsorption sites first, thus effectively preventing H 2 O entry into MOF pores to contact with hydrophilic metal sites. This realized high water resistance and toluene adsorption uptake under high humidity conditions. Results showed that D-MIL-101 had a high specific surface area of 2558 m2/g and a new microporous structure of 9.5 Å size. It presented higher toluene uptake of 4.69 mmol/g at lower vapor pressure of P / P 0 = 0.013 and 298 K temperature, as well as 3.3 folds higher working capacity of toluene compared to pristine MIL-101 under 80 % RH. This study presents a novel approach for constructing hydrophobic MOFs using new positive charging ligands and delves deeper into the competitive adsorption of VOCs/H 2 O in MOF composites for large-scale applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Carboxymethyl cellulose sodium (CMC) was used to in-situ synthesize foam HKUST-1. • CMC modulated HKUST-1 crystal into huge cubic shape (5.0 μm) with high surface area. • CMC embedded into foam HKUST-1 with Cu O clusters and formed a unique interface. • At P/Po ∼ 0.0026, foam HKUST-1 bared 5.2 times higher toluene uptake than MIL-101(Cr). • Chitosan modified foam HKUST-1 exhibited highest selectivity for acidic dipeptide. Abstract A green and in-situ metal-organic framework (MOF) shaping strategy was proposed to fabricate cellulose foam HKUST-1 and modify with polysaccharides for convenient adsorption applications. The obtained unique foam HKUST-1 not only maintains HKUST-1 intrinsic thermal stability and high surface area, but also exhibits unique crystal structure and interface for HKUST-1. Moreover, the surface and crystal size of foam HKUST-1s can be easily modulated with natural polysaccharides, and the crystal and novel interfaces awarded them 5.2 times higher adsorption uptake (4.52 mmol/g) for vapor-toluene than MIL-101 (Cr) under low pressure P/Po ≈ 0.0026 and high selectivity (1 0 7) for acidic/basic dipeptides EE/RR. Based on the above results, the novel foamed MOFs can be applied for volatile organic compounds (VOCs) adsorption under ambient condition and improve acidic dipeptides enrichment in liquid phase. It will play a significant role as adsorbent in practical adsorption applications. [ABSTRACT FROM AUTHOR]

Construction of highly-active photothermal catalysts featuring merits of high quantum efficiency and superior heat resistance is a great challenge during volatile organic compounds (VOCs) degradation under high humidity. Herein, a facile solvent-induced dimensionality reduction strategy was proposed to engineer a nanosheeted and polycrystalline Cu/Mn-based catalyst (M-Cu/MnO x) having interfacial oxygen vacancies for enhanced photo-thermal catalytic degradation of toluene under highly humid conditions. Unique Cu-mediated δ-MnO 2 /Mn 3 O 4 nanosheets with high surface area exhibited excellent light absorptivity and photogenerated carrier separation efficiency, as well as superior light-driven thermogenesis. It realized ultra-high (92.8%) toluene conversion and deep mineralization (84.4%) under RH = 80% and continuous catalytic reaction (200 h). Its toluene degradation rate exhibited 3.5–71.9 times higher than reported state-of-the-art photothermal catalysts. The newly designed M-Cu/MnO x catalyst provides a promising, low-cost and alternative for the efficient degradation of toluene and other similar VOCs under humid conditions on large-scale operations. [Display omitted] • Cu/MnO x nanosheets with abundant O V are engineered by facile solvent-induced strategy. • Cu/MnO x nanosheets have superior light absorption and photothermal conversion ability. • Photothermal synergism activates O V to achieve low-temperature toluene degradation. • Cu/MnO x displayed 3.5–71.9 times higher toluene degradation rate than reported catalysts. • Cu/MnO x showed excellent long-lasting (∼ 200 h) photothermal catalysis for toluene. [ABSTRACT FROM AUTHOR]

[Display omitted] • Heat-conductive HKUST-1@BNNS was fabricated for toluene efficient ad-/de-sorption. • Tight interface maintained high surface area of MOF and embedded BN weak-polar surface. • HKUST-1@BNNS showed very high C 7 H 8 adsorbed uptake (4.3 mmol/g) at ultra-low pressure. • BNNS improved heat diffusion for HKUST-1@BNNS and speeded up its C 7 H 8 desorption rate. • HKUST-1@BNNS showed 2 and 4 folds of heat transfer and C 7 H 8 desorption rate of HKUST-1. Improving the adsorption capacity of the volatile organic compounds (VOCs) will inevitably decrease the desorption efficiency and hence increase more energy-consumption, which has become a crucial challenging problem for MOFs modification and composition toward VOCs adsorption. Herein, a thermal-conductive composition strategy was proposed to anchor BN nanosheets (BNNS) into HKUST-1 crystals via "N/O-Cu-O" interface. The formed HKUST-1@BNNS composite maintained high surface area (1633.7 m2/g having more microporous) and enhanced heat diffusivity (1.8 times of HKUST-1), simultaneously. This enabled significant increase of toluene adsorption capacity on HKUST-1@BNNS up to 4.3 mmol/g (2.8 times of HKUST-1) at ultra-low pressure (P / P 0 ≈ 0.001) and higher desorption rate of toluene (k ds = 29.3 × 10−2, 4.0 times of HKUST-1) with lower desorption activation energy (E d = 33.5 kJ/mol). Compared with many other state-of-the-art adsorbents (e.g., MOFs, zeolites and activated carbons), it has a much higher adsorption capacity and regeneration rate. Thus, thermal-conductive MOFs construction can be deemed as smart strategy to enhance adsorption efficiency and save desorption energy for VOCs capture. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel MOF composite film with heat-conducting network is constructed with HKUST-1 and BNNS. • Hierarchical porous and heat-conductive nanofibers network promote toluene ad-/desorption efficiency. • Unique BNNS-CA-O|Cu|O-ligand interface enhances MOF film adsorption affinity and capacity for toluene. • Thermal diffusion performance of HK-mB/P film is 2.6 times higher than that of powder HKUST-1. • HK-mB/P film exhibits ∼5–6 times higher ad-/desorption rate for toluene than powder MOF. Metal-organic frameworks (MOFs) modification and composite to chase high adsorption capacity and desorption efficiency for volatile organic compounds (VOCs) capture are a great challenge work. Seeking a suitable strategy to simultaneously promote the adsorption capacity and regeneration efficiency of MOFs is a significant practical challenge in this context. Herein, novel heat-conducting MOFs (HKUST-1) composite films were prepared for efficient and synchronous improvement of adsorption affinity and desorption efficiency. In our case, bulk Boron nitride (BN) was exfoliated into BN nano-sheets (BNNS), which were then spread as flakes on PVDF nanofibers to form a conductive network (BNNS/PVDF film, which was abbreviated as B/P film). With the aid of citric acid (CA) modification, HKUST-1 crystals were dispersed-grown on modified B/P (mB/P) film, resulting in the formation of a hierarchical pore structure in HK-mB/P film with a relatively high MOFs loading amount (45.8 wt%) and surface area (448 m2/g). Performance evaluation experiments showed that the toluene adsorption and desorption rates of the HK-mB 0.4 /P 0.6 film were 5.5 and 5.3 times higher than those of the powder HKUST-1, respectively. The fast adsorption rate could be ascribed to the constructed heat-conducting network and porous stacked nanofibers. Furthermore, its adsorption capacity for toluene was significantly increased up to 4.69 mmol/g at low pressure (P / P 0 = 0.01), which was approximately-two times higher than that of pure HKUST-1. This merit was mainly attributed to the newly formed interface between HKUST-1 and mBNNS, which could strengthen the adsorption affinity for toluene by the generated unsaturated metal sites of (BNNS-CA-O|Cu|O-ligand) and π-π attraction of B-N bonds. Besides, the HK-mB 0.4 /P 0.6 film also displayed good cycling performance, with only a 3–4 % decrease in activity observed after five consecutive cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cr-N anchors were pre-load on tubular carbonized N-doped polymer (TCNP). • MIL-101(Cr/Cu) on Cr-TCNP via N-Cr-O interface constructed hydrophobic interface. • Insertion of TCNP and Cu enhanced π-π conjugation and electrostatic interaction between toluene and [TCNP 5 /MIL(Cr/Cu)] N-Cr. • [TCNP 5 /MIL(Cr/Cu)] N-Cr showed 2.9 times higher toluene uptake than MIL-101 at P / P 0 = 0.02. • [TCNP 5 /MIL(Cr/Cu)] N-Cr exhibited 2.1 times higher toluene capacity than MIL-101 under 80% RH. High capacity adsorption of volatile organic compounds (VOCs) in high humidity environment is a crux but challenge for atmospheric VOCs governance. In this work, tubular carbonized N-doped polymers (TCNP) were implanted into MIL-101 via N-Cr-O interface self-assembly, enabling high adsorption for vapor toluene in high humidity. Through mechanical ball milling and carbonization, Cr ions were preloaded on TCNP to form highly dispersed 3–5 nm Cr-N crystallite as anchors for growing MIL-101(Cr/Cu). Newly constructed smaller micropores of 6.8 Å with aromatic rings/N sites at the interface and doped Cu ions in MOF framework synergistically enhanced π-π conjugation and electrostatic interaction for C 7 H 8 molecules. This endowed [TCNP 5 /MIL(Cr/Cu)] N-Cr 2.9 times higher toluene uptake (6.34 mmol/g) at low vapor pressure (P / P 0 = 0.02) and 1.9 times diffusivity under high humidity (60% RH) than that of MIL-101(Cr) at 298 K. The adsorption breakthrough curves for vaporous toluene showed that TCNP@MIL-101(Cr/Cu) exhibited outstandingly higher adsorption equilibrium capacity (2.7 mmol/g) under 80% RH, corresponding to approximately 2–10 times than those of reported state-of-the-art adsorbents under similar conditions. This study provided a novel interface construction strategy for hydrophobic MOF composites, which supplied deeper understanding for VOCs adsorption and promoted MOFs practical application in VOCs capture under humid environment. [ABSTRACT FROM AUTHOR]

[Display omitted] • NH 2 -MIL(Ti)-125 was confined grown into via 'ship-in-the-bottle' synthesis approach by Ti-clusters anchored OMC. • Hydrophobic shell (OMC) enhanced surface non-polar and humidity resistance on MIL(Ti)@OMC Ti. • MIL(Ti)@OMC Ti achieved interconnected micro-/mesoporous networks and accelerated mass transfer. • MIL(Ti)@OMC Ti showed high moisture-resistance and adsorption affinity for toluene at ultra-low pressure. • the mechanism of selective toluene adsorption and recycling performance were deeply investigated. Competitive adsorption of volatile organic compounds (VOCs) under high humidity is a critical but challenging issue in the applications of metal–organic frameworks (MOFs). In this work, hydrophobic-shell structured NH 2 -MIL(Ti)-125@mesoporous carbon composite was designed to enhance selective adsorption towards VOCs under humid conditions via confined growth strategy. Ti-clusters were first anchored into pores of ordered mesoporous carbon (OMC), and then confined grown into NH 2 -MIL(Ti)-125 via 'ship-in-the-bottle' approach. Hydrophobic shell of OMC concurrently protected the adsorption sites on NH 2 -MIL(Ti)-125 from H 2 O occupation and enhanced affinity towards non-polar toluene. Moreover, the resulting composited supplied abundant diffusion channels for toluene thereby accelerated the mass transfer though mesopores (OMC) and micropores (MOFs). As expected, the hydrophobic-shell NH 2 -MIL(Ti)-125@OMC composite efficiently enhanced hydrophobic property and toluene adsorption affinity. It obtained a dramatical increase in toluene adsorption capacity (3.86 mmol/g at 0.001 P / P 0) about 7.4 times of NH 2 -MIL(Ti)-125, and a 29% decrease in water vapor adsorption capacity (0.30 g/g at 1 mbar), which much superior than many reported expensive adsorbents. In addition, the composite induced more confined micropores to mesopores interconnected structure in MIL(Ti)@OMC Ti , and hence facilitated toluene diffusion. The toluene rate constant of pseudo-second-order adsorption (k a) on the MIL(Ti)@OMC Ti was up to 0.12 g/(mmol∙min), which was 1.2–2.0 times higher than those of the MIL(Ti) species. Moreover, breakthrough curve indicated that MIL(Ti)@OMC Ti showed 1.5 times of toluene working capacity with faster diffusivity at 80% RH compared to pure NH 2 -MIL(Ti)-125, while the latter exhibited much lower value of Q w / Q e than that of the former. This work provides a novel composite strategy for hydrophobic MOFs construction, and deeper understanding for VOCs/H 2 O competitive adsorption on MOFs composites in large scale applications. [ABSTRACT FROM AUTHOR]

• Short-chains PEG is implanted into MIL-101 cage via coordination of –OH with Cr3+. • PEG is proved to form a hydrophobic barrier and raise H 2 O diffusion resistance. • Formed novel pore (11.2 Å) enhances dispersion force to toluene showing high uptake. • PEG restricts H 2 O diffusion in their implanted area but has less effect on toluene. • PEG 5 @MIL-101 shows 3.3 times of toluene working capacity than MIL-101 at 80% RH. Adsorption of volatile organic compounds (VOCs) under high humidity is crucial for metal–organic frameworks (MOFs) in practical applications. To enhance competitive adsorption of VOCs under humidity, polyethylene glycol (PEG) with hydrophobic short-chains was implanted as hydrophobic barrier into MIL-101(Cr). Characterization and simulation results showed that the terminal –OH groups of PEG chains were coordinated with the Cr sites in MIL-101(Cr) and formed a hydrophobic pore (11.2 Å) of "cage-in-cage" geometry. PEG chains significantly hindered the diffusion of water into the MOFs while allowed toluene molecules. The new hydrophobic pores of PEG 5 @MIL-101 enhanced adsorption capacity and diffusivity for toluene by 30.8% (4.68 mmol/g at 1 mbar) and 31.5% (1.88 × 10−2), while decreased adsorption capacity and diffusivity for water by 53.7% and 26.8% compared to primary MOF. Breakthrough curve showed 3.3 times of toluene working capacity on PEG 5 @MIL-101 at 80% RH compared to pristine MIL-101(Cr). [ABSTRACT FROM AUTHOR]