High Pore Volume Research Articles

Cu3(BTC)2 metal organic framework as a promising adsorbent for operative exclusion of toxic dyes and herbicide

Synthetic organic dyes and herbicide pollutants pose a significant threat to water quality due to their high solubility in water and widespread industrial discharge. In water conservation developments, the Metal-Organic Frameworks (MOFs) are considered confident and substantial for the exclusion of toxic organic dyes, due to their multi-potential assets of cost-effective, high pore volume, high thermal stability, easy adaptation to toxic dye molecules, and most of them are stable in water, etc. Hence, the green synthetic methodology was employed for the combination of Cu3(BTC)2 MOF, which is draped with carboxylate functionality ligands, as an adsorbent to remove the hazardous dyes of Methyl Orange (MO), Acid Yellow (AY), and toxic herbicide of Atrazine (ATZ) from contaminated wastewater. As-reported Cu3(BTC)2 was evidently characterized by XRD, FTIR, TGA, XPS, SEM, and EDAX analysis. The equilibrium adsorption capacity (Qe) value of as-reported Cu3(BTC)2 for AY, MO, and ATZ was better in comparison with the formerly reported adsorbent. The high adsorption capacity of Cu3(BTC)2 for AY (777 mg/g), MO (903 mg/g), and ATZ (484 mg/g) is principally explained by π-π and electrostatic interaction. As a result, Cu3(BTC)2 is reported and proposed as a suitable adsorbent for the abolition of toxic dyes and herbicides from contaminated water.

Highly porous biocarbon monoliths for methane storage

Pollution, resulting from the use of gasoline and diesel fuels, presents an evident concern to environmental health and safety, contributing to greenhouse gases, smog, and a plethora of other hazards to everyday life. A variety of alternative energy sources and technologies are being considered towards the reduction of pollution from the use of fossil fuels, one such being natural gas. The bottleneck of technology for natural gas implementation is the storage and distribution at ambient condition with low-cost media. Activated carbon materials, having been further popularized for their adsorbent properties, have become established as a popular choice for natural gas storage thanks to their high pore volume and surface area and the abundant availability of carbon precursors. Herein, the synthesis of activated carbon monoliths and their application for methane adsorption, as it relates to natural gas storage, is described.

Unveiling the Potential: Selecting Optimal Materials for Physical Pools in a Pavement-Runoff-Integrated Treatment System

Pavement runoff contains complex pollutants that can lead to environmental pollution and health risks. A pavement-runoff-integrated treatment system has been recognized as an effective way to deal with pavement runoff pollution. However, there is little support for selecting appropriate materials for physical pools due to a lack of understanding of the selective filtration and physical adsorption characteristics. In this study, gravel and activated carbon were chosen as the substrate materials for physical filtration and adsorption pools, and their corresponding purification characteristics were investigated using an indoor scaled down model. The results showed that the removal rate of all pollutants was related to the size of the gravel used. This was mainly due to the increased gravel particle size and voids, which resulted in a higher water velocity, shorter hydraulic retention time, and inadequate filtration. Compared with coconut shell granular activated carbon (GAC) and coal column activated carbon (EAC), analytically pure granular activated carbon (ARAC) showed a better removal rate for petroleum and heavy metals. This is mainly because ARAC has a larger specific surface area, higher pore volume, and wider pore size distribution, resulting in a remarkable adsorption capacity for pollutants. Overall, the combination of 0.3 mm gravel and ARAC was found to be the most suitable for use as filtration and adsorption materials for physical pools. These findings offer a gravel- and ARAC-based pavement-runoff-integrated treatment system, which has excellent potential to enhance the removal of pollutants from pavement runoff.

Synthesis of visible light-sensitive photocatalysts for hydrogen production

Photocatalysis is a promising way to produce green hydrogen from water under sunlight. However, it is still challenging to develop an efficient photocatalyst for hydrogen production that works under sunlight with high efficiency. In this study, sincere efforts have been made to develop a photocatalyst with enhanced light absorption within the visible spectrum and improved separation of photogenerated electron-hole (e-/h+) pairs. Phosphorus and Nickel codoped TiO2 (PNT) photocatalysts were synthesized through the sol–gel method by varying the amount of phosphoric acid, nickel nitrate, and calcination temperature. Photoluminescence and UV–Vis spectroscopy confirm that codoping enhances the separation of photogenerated e-/h+ pairs as well as improves visible light absorption. Codoped TiO2 had a higher specific surface area and higher pore volume than doped and pure TiO2. 1.5 wt% P and 3.0 wt% of Ni codoped TiO2 calcined at 400 °C (3.0 PNT 400 °C) shows the highest H2 production from water (266.471 μmolg-1h−1) and simulated seawater (148.536 μmolg-1h−1) under solar simulator bulbs in the presence of Ethylene Glycol (10 vol%). This photocatalyst exhibits good stability, with a slight reduction in hydrogen production of 9.15 % in water and 14.8 % in simulated seawater after four cycles.

Green synthesis of Kenaf-based activated carbons with excellent rate capability and cycle-life via hydrothermal-co-activation process for high-performance capacitive energy storage

The invention of high-performance electrode materials through a simple and green approach is always important for energy storage applications. Herein, we have prepared highly porous activated carbons (ACs) from biomass kenaf (KF) by hydrothermal and steam activation methods. A number of optimization experiments, such as hydrothermal pre-treatment (100, 150 and 200 °C), steam activation temperature (600, 700, 800, and 900 °C) and time of steam flow (15, 30, 60 and 90 min) were performed to control the specific surface area, micro- and/or meso-pores, total pore volume for an excellent electrochemical performance. The as-obtained porous ACs exhibited a high specific surface area (∼1733 m2/g) with high total pore volume (∼0.916 cm3/g) and high mesopore volume (∼28.4%), which are beneficial for the excellent double layer formation over the surface of activated electrode and also provide transport channel for an effective diffusion of electrolyte ions. The as-derived ACs were used as electrode materials for the fabrication of symmetric supercapacitor device in 6 M KOH. The fabricated device exhibited a high energy density of 4.86 Wh kg−1 at power density of 2500 W kg−1 with outstanding stability (∼96.3%) over 10,000 charge-discharge cycles.

Highly Stable Amide-Functionalized Zirconium-Organic Frameworks: Synthesis, Structure, and Methane Storage Capacity.

With the development of crystalline porous materials toward methane storage, the stability issue of metal-organic framework (MOF) materials has caused great concern despite high working capacity. Considering the high stability of zirconium-based MOFs and effective functions of amide groups toward gas adsorption, herein, a series of UiO-66 type of Zr-MOFs, namely, Zr-fcu-H/F/CH3/OH, were successfully designed and synthesized by virtue of amide-functionalized dicarboxylate ligands bearing distinct side groups (i.e., -H, -F, -CH3, and -OH) and ZrCl4 in the presence of trifluoroacetic acid as the modulator. Single-crystal X-ray diffraction and topology analyses reveal that these compounds are archetypal fcu MOFs encompassing octahedral and tetrahedral cages, respectively. The N2 sorption isotherms and acid-base stability tests demonstrate that the materials possess not only relatively high surface areas, pore volumes, and appropriate pore sizes but also great hydrolytic stabilities ranging pH = 3-11. Furthermore, the volumetric methane storage working capacities of Zr-fcu-H, Zr-fcu-F, Zr-fcu-CH3, and Zr-fcu-OH at 298/273 K and 80 bar are 187/217, 175/193, 167/187, and 154/171 cm3 (STP) cm-3, respectively, which indicate that the zirconium-based crystalline porous materials are capable of storing relatively high amounts of methane.

Synthesis and electrochemical properties of porous carbon materials from sludge sources

Anaerobic digestion sludge technology is a green and efficient method of treating sludge. However, the presence of humic acid (HA) in sludge can inhibit methanogenic efficiency, and it is necessary to reduce its impact on biogas production by removal or pretreatment. HA, a graphene oxide material can be used to produce high-performance energy-storage materials. Thus, this study examined the sludge source of HA as a precursor, and different electrode materials were prepared by varying the reaction conditions. The structure and electrochemical properties of the electrode materials were analyzed. The results showed that the electrode material prepared using KOH as an activator at 700 °C exhibited optimal performance, with a high specific surface area (1480.53 m2·g−1), pore volume (0.943 cm3·g−1), specific capacitance (185.9 F·g−1), and equivalent series resistance (0.73 Ω). The material maintained 97.8% of its specific capacitance after 1000 cycles at a current density of 1 A·g−1 with benign cycle stability. This study confirmed that the production of HA as an electrode material at a low cost with good performance presents significant prospects.

Research Progress on Metal–Organic Framework-Based Electrode Materials for Supercapacitors

Supercapacitors play an important role in power systems since they are a key part of electrochemical energy storage devices. To assemble high-performance supercapacitors, it is crucial to discover and innovate high-capacitive electrode materials. Recently, metal–organic frameworks (MOFs) and their derivatives have received wide concerns as electrode materials for supercapacitors, not only because of their high pore volume and large surface area for ions and electrons insertion and transportation, but also due to the intrinsic metal active sites that possibly offer extra faradaic pseudocapacitance. Additionally, the abundant species of MOFs with various morphologies also feature advantages in enriching the structural diversity of electrodes. In this paper, we first report the latest research progress and demonstrate the feasibility of pure MOFs for directly constructing supercapacitor electrodes. Furthermore, different MOF derivatives, including porous carbons, transition metal oxides, metal hydroxides and MOF composites for supercapacitors, are summarized, and their electrochemical performances with corresponding energy storage mechanisms are presented in detail. Finally, the perspectives for MOF-based materials applied in supercapacitors are discussed, aiming to provide a guideline for further research based on these promising materials.

Adsorption of Lead from Aqueous Solution Using Activated Carbon Derived from Rice Husk Modified with Lemon Juice

In the present work, activated carbon (RHAC-LJ) was synthesized utilizing rice husk as a carbon source that is activated with lemon juice. Moreover, the adsorptive capacity of RHAC-LJ in removing Pb(II) from aqueous solution was investigated. FTIR analysis revealed the presence of amides, alkenes, carboxyl and hydroxyl groups in RHAC-LJ. SEM micrographs illustrate that activation with lemon juice resulted in high pore volume and greater pore diameter. Activation using acid from lemon juice can remove impurities from the adsorbent surface. The surface area and pore volume of RHAC-LJ were determined to be 112.87 m2·g−1 and 0.107 cm3/g, respectively. Adsorption kinetics followed the pseudo-second-order equation (R2 = 0.9941) with a rate constant of 3.3697 g/mg·min for Pb (II), which indicates chemisorption to be the rate-determining step of the process. The BBD model using RSM was applied in studying the effects of pH, stirring speed and adsorbent dosage and their interactions on the removal efficiency of RHAC-LJ. Analysis of variance was used to examine the significance of the model, independent parameters, and their interactions. Moreover, a removal efficiency of 98.49% can be attained using the following optimal conditions: 197 rpm, pH 5.49, and adsorbent dosage of 0.3487 g. Overall, the present work illustrates RHAC-LJ as a potential low-cost adsorbent for the removal of Pb(II) from synthetic wastewater.

Top-Down Thickness Reduction Synthesis of Biomass-Derived Carbon Nanosheets with Hierarchical Pore Structure for High-Performance Supercapacitors.

Carbon electrode materials with superior rate performance are highly demanded in application scenarios of high power output/input, especially when paired with organic electrolyte for extended voltage window and high energy storage. By extracting thin sheets of entangled cellulose fibers from cell wall structures, porous carbon nanosheets as templated from the cellulose sheets are synthesized. Evident thickness reduction effect has been demonstrated with thickness reduced from several micrometers to several nanometers of the obtained thickness-reduced activated carbon nanosheets (TRAC), which endow the material with a large surface area and high pore volume. The obtained TRAC exhibits significantly enhanced ion diffusion kinetics and superior rate capability thanks to the shortened diffusion pathway and suitable pore size distribution. Effects of sonication time have also been investigated, showing a trade-off between ion diffusion kinetics and pseudocapacitive contribution. This thickness-reduction method is extendable to many other biomass sources as cellulose sheets are widely existed in nature, offering a practical and easy-to-implement strategy of fabricating porous carbon nanostructures for efficient energy storage and utilization.

Synthesis and Characterization of Core-Shell Mesoporous Iron oxide Magnetic Nanoparticles using Modified Co-Precipitation Method

In recent era, development of nanotechnology is an art of delivery of drug by improving its compatibility, effectiveness and efficacy. Among all nanoparticles, magnetic nanoparticles play a predominant role to shows their targeted drug delivery using a magnetic field, also helps to diagnose the diseases like cancer. The present study included preparation of four different mesoporous nanoparticles using the Pluronic block copolymer P123 as a surfactant template, then insert iron oxides using co-precipitation method. The resulted formed mesoporous magnetic nanoparticles are examined for structural characters by using FTIR, XRD, HRSEM and Elemental Mapping techniques. The results of X-ray diffraction (XRD) showed that the formed composites conserved ordered mesoporous structure after the formation of iron oxide nanoparticles in the pores. FTIR results indicated that the surface contains silanol group and Fe–O on the surface of the materials at 1060 cm-1 and 1020 cm-1 peaks respectively. Scanning electron microscopy (SEM) results showed that all mesoporous magnetic nanoparticles within the range of size from 50 to 100nm also possessed a regular spherical shape. These particles possessed high surface area, high pore volume and showed magnetic response sufficient for drug targeting in the presence of an external magnetic field. Elemental mapping data indicated about the percentage of all elements present in the mesoporous materials. We concluded that all four types of magnetic nanoparticles are structurally arranged in their structure with sufficient percentage of elements on their particle surface along with good size range. Further loading of drug into all types of magnetic nanoparticles decides the loading efficiency, stability and drug release nature.

Self-templating synthesis of biomass-based porous carbon nanotubes for energy storage and catalytic degradation applications

Dwindling energy sources and a worsening environment are huge global problems, and biomass wastes are an under-exploited source of material for both energy and material generation. Herein, self-template decoction dregs of Ganoderma lucidum-derived porous carbon nanotubes (ST-DDLGCs) were synthesized via a facile and scalable strategy in response to these challenges. ST-DDLGCs exhibited a large surface area (1731.51 m2 g−1) and high pore volume (0.76 cm3 g−1), due to the interlacing tubular structures of precursors and extra-hierarchical porous structures on tube walls. In the ST-DDLGC/PMS system, the degradation efficiency of capecitabine (CAP) reached ∼97.3% within 120 min. Moreover, ST-DDLGCs displayed high catalytic activity over a wide pH range of 3–9, and strong anti-interference to these typical and ubiquitous anions in wastewater and natural water bodies (i.e., H2PO4−, NO3−, Cl− and HCO3−), in which a 1O2-dominated oxidation was identified and non-radical mechanisms were deduced. Additionally, ST-DDLGC-based coin-type symmetrical supercapacitors exhibited outstanding electrochemical performance, with specific capacitances of up to 328.1 F g−1 at 0.5 A g−1, and cycling stability of up to 98.6% after 10,000 cycles at a current density of 2 A g−1. The superior properties of ST-DDLGCs could be attributed to the unique porous tubular structure, which facilitated mass transfer and presented numerous active sites. The results highlight ST-DDLGCs as a potential candidate for constructing inexpensive and advanced environmentally functional materials and energy storage devices.

Influence of Co3O4 Nanostructure Morphology on the Catalytic Degradation of p-Nitrophenol.

The design and fabrication of nanomaterials with controllable morphology and size is of critical importance to achieve excellent catalytic performance in heterogeneous catalysis. In this work, cobalt oxide (Co3O4) nanostructures with different morphologies (nanoplates, microflowers, nanorods and nanocubes) were successfully constructed in order to establish the morphology-property-performance relationship of the catalysts. The morphology and structure of the nanostructured Co3O4 were characterized by various techniques, and the catalytic performance of the as-prepared nanostructures was studied by monitoring the reduction of p-nitrophenol to p-aminophenol in the presence of excess NaBH4. The catalytic performance was found to be strongly dependent on their morphologies. The experimental results show that the pseudo-first-order reaction rate constants for Co3O4 nanostructures with various shapes are, respectively, 1.49 min-1 (nanoplates), 1.40 min-1 (microflowers), 0.78 min-1 (nanorods) and 0.23 min-1 (nanocubes). The Co3O4 nanoplates exhibited the highest catalytic activity among the four nanostructures, due to their largest specific surface area, relatively high total pore volume, best redox properties and abundance of defect sites. The established correlation between morphology, property and catalytic performance in this work will offer valuable insight into the design and application of nanostructured Co3O4 as a potential non-noble metal catalyst for p-nitrophenol reduction.

Creating high-affinity binding sites for efficient CO2 and iodine vapor uptake through direct synthesis of novel triazine-based covalent organic polymers

Two types of triazine-based covalent organic polymers were successfully constructed through a one-pot and catalyst-free polycondensation approach. More specifically, two kinds of aromatic aldehyde containing different hydroxyl content named terephthalaldehyde and 2, 4, 6-trihydroxyisophthalaldehyde were selected and the derived polymers (denoted as POPs-1 and POPs-2) with large Brunauer-Emmett-Teller (BET) surface areas (> 360 m2/g), high total pore volume (> 0.47 m3/g), good stability and different heteroatoms (such as N and O) contents were prepared. Interestingly, POPs-1 featuring high BET surface area and N content (up to 34.83 %) exhibited excellent iodine vapor uptake of 441 wt% at 348 K/1.0 bar, POPs-2 with high O content (up to 25.83 %) showed better CO2 adsorption capacity (91.8 mg/g) at 273 K/1.0 bar and higher isosteric heat of adsorption (up to 85.0 kJ/mol) than that of POPs-1. This value of the isosteric heat is the highest value reported to date for porous organic polymers. This excellent adsorption performance was resulted either from the large BET surface area or high heteroatoms (N and O) contents of the porous adsorbents. The study offer an alternative route to develop high-performance porous adsorbents to capture carbon dioxide and iodine.

Porous nanosheets of TKX-50 by ice-templating strategy with excellent thermal decomposition and combustion properties

ABSTRACT Nanostructured energetic materials have attracted considerable research interests during the past decades because of their improved performances in thermal decomposition and combustion. In this work, a porous nanosheet structure of dihydroxylammonium 5, 5′-bistetrazole-1, 1′-diolate (TKX-50) has been fabricated by a facile ice templating strategy, which is based on the self-assembly of TKX-50 during rapid recrystallization. Thermal decomposition properties were determined by differential scanning calorimetry/thermogravimetry (DSC/TG) and TG-FTIR analyses. The laser-ignited and constant-volume combustions and mechanical sensitivity were conducted. As-prepared TKX-50 mainly presents porous nanosheets (NS-TKX-50) assembled by the secondary nanoparticles. NS-TKX-50 is typical of mesoporous materials with high specific surface area and pore volume. Compared with raw material, NS-TKX-50 exhibits lower thermal decomposition peak temperature and higher active energy. In thermal decomposition process, a great deal of gaseous products have been generated in a very narrow temperature range. These thermal decomposition features suggest a quick energy-release rate and high energy output. Contrary to incomplete combustion of raw material, NS-TKX-50 shows high-efficiency and self-sustaining laser-ignited combustion feature with a drastically decreased ignition threshold. And its pressurization rate and peak pressure are remarkably increased. Sensitivity results confirmed the visibly reduced impact and friction sensitivity of NS-TKX-50.

High-efficient removal and adsorption mechanism of organic dyes in wastewater by KOH-activated biochar from phenol-formaldehyde resin modified wood

The treatment of wastewater contaminated with organic dyes has become an intricate challenge in water pollution control. Currently, sophisticated chemical modifications and synthetic methods are frequently needed to enhance the adsorption capacity of biochar for removing dyes during the treatment process. In order to develop a facile, low-cost and efficient biochar absorbent, an activated biochar (KOH/PF-WB) was successfully synthesized from phenol-formaldehyde (PF) resin modified wood via pyrolysis and potassium hydroxide (KOH) activation. Based on the joint effect of PF resin and wood, KOH/PF-WB-700–2 exhibited a remarkable porous structure and abundant oxygen-containing functional groups, which resulted in a substantially high specific surface area (SBET = 2301.61 m2/g) and total pore volume (Vtotal = 1.205 cm3/g). Additionally, the PF resin modification led to increased disorder and more defect sites of activated wood biochar. As a result, KOH/PF-WB-700–2 demonstrated superior adsorption capacity for congo red (3472.22 mg/g) and methylene blue (1112.35 mg/g) dyes compared to some reported adsorbents. The adsorption process could be better described by the pseudo-second-order kinetic model and Langmuir isotherm model, while the overall process was spontaneous and feasible. The primary adsorption mechanism involved pore filling through the modulation of PF resin, along with the cooperative effects of electrostatic attraction, hydrogen bonding and π-π interaction. This finding provides a viable strategy for the waste PF-modified wood cyclic application, and offer technical support for the prospect of KOH/PF-WB for the removal of organic dyes.

Metal oxide and nitrate-modified calcium gluconate-based sorbent with high stability for integrated carbon capture and utilization process

In this study, metal oxides (MgO, CeO2, and Al2O3) and metal nitrates (Mn(NO3)2, Al(NO3)3, Mg(NO3)2, and Fe(NO3)3) were used to modify calcium gluconate-based sorbents for the integrated CO2 capture and utilization (ICCU) process. We employed conventional thermogravimetric analysis (TGA) and microfluidized bed thermogravimetric analysis coupled with mass spectrometry (MFB-TGA-MS) to explore the cyclic CO2 capture behavior, physical and chemical properties, and morphology in detail. Our findings reveal that calcium gluconate modified with aluminum nitrate (CG-Al-N) exhibited superior CO2 capture capacity (9.81 mmol∙g−1 over 20 cycles), along with a high surface area (35.67 m2∙g−1) and pore volume (0.16 cm3∙g−1). In comparison, pure calcium gluconate displayed a capacity of 7.09 mmol∙g−1, a surface area of 27.66 m2∙g−1, and a pore volume of 0.06 cm3∙g−1, while commercial calcium oxide demonstrated 1.96 mmol∙g−1, 4.62 m2∙g−1, and 0.01 cm3∙g−1, respectively. Notably, after 100 cycles, CG-Al-N retained a CO2 capture capacity of 11.75 mmol∙g−1, achieving 66% of the capacity of the pure CaO sorbent. This observation strongly suggests that CG-Al-N has excellent anti-sintering properties. Furthermore, data was acquired under fluidized and isothermal conditions by utilizing MFB-TGA-MS. CG-Al-N consistently exhibited an average CO2 capture capacity (9.57 mmol∙g−1), CO yield (5.00 mmol∙g−1), and CO selectivity (∼100%) over 20 ICCU cycles, with the dominant route being the reverse water–gas shift (RWGS) reaction, highlighting the self-catalytic activity of gluconate-based sorbents. Morphological evolution also revealed finer pores and a skeleton structure of cycled CG-Al-N, which affirms the unobstructed gas entry and ensures a continuous gas–solid reaction.

Towards electron-transfer-driven peracetic acid oxidation: Catalytic performance adaptation of reduced graphene oxide to explosive thermal exfoliation

Direct electron transfer (DET)-mediated carbon/peracetic acid (PAA) oxidation systems are gaining momentum in water treatment owing to high selectivity and robustness in complex water matrices. However, the development of reaction-oriented and high-performance carbon catalysts for PAA oxidation is hindered by a limited understanding of the fundamental relationship between carbon structure and PAA activation performance. In this work, we focused on exploring the influence cascade of thermal annealing, especially explosive thermal exfoliation, on the catalytic performance adaptation of reduced graphene oxide (rGO) in PAA oxidation. By performing structure-performance relationship studies and Pearson correlation analyses, the improved catalytic efficacy of rGO is attributed to the induced high specific surface area (SSA) and pore volume of rGO in explosive thermal exfoliation. Large SSA and pore volume of rGO reinforce the DET pathway via the elevated PAA adsorption quantity and subsequent enhanced oxidative potential of the rGO-PAA complex, which are critical premises in initiating DET. Furthermore, increased annealing temperatures can tailor the graphitization level and functional group content of rGO, leading to the improved electrical conductivity of rGO, another crucial factor in DET-mediated rGO/PAA oxidation. This study emphasizes the key role of carbon physicochemical properties in PAA activation, providing insights into the rational design of DET-oriented carbon/PAA oxidation systems for fast water decontamination.

The role of transition metal doping in enhancing hydrogen storage capacity in porous carbon materials

Porous carbon materials with high specific surface area are potential hydrogen storage materials. However, due to the weak van der Waals forces between the material and H2, hydrogen can generally be stored only at a cryogenic temperature under high hydrogen pressure. To solve this problem, in this work, ZIF-8-derived porous carbon material (PCM) modified with transition metals (PCM-TMs, TM: Mn, Fe, Ni) was prepared to investigate the role of TM doping. The developed PCM-TMs have a high specific surface area (up to 1363 m2/g) and pore volume (up to 0.77 cm3/g). Experimental results show that PCM-TMs exhibit higher hydrogen storage capacity, usable capacity, and hydrogen uptake capacity per specific surface area compared to PCM. In addition, PCM-TMs have a higher isosteric heat of adsorption (Qst) than PCM, which suggests that TM doping enhances the interaction between H2 and carbon materials. Theoretical calculations further indicate that this interaction is a nearly weak chemisorption force (∼9.32 kJ/mol). Notably, Mn-doped porous carbon material (PCM-Mn) exhibits a hydrogen storage capacity of ∼3.45 wt% (20.44 g/L) at 77 K under 35 bar-H2. Even at 253 K under 50 bar-H2, the capacity can reach ∼1.41 wt% (8.34 g/L). The hydrogen uptake capacity per specific surface area for PCM-Mn reaches 1.03 × 10-3 wt% / m2·g-1 at 253 K under 50 bar-H2, which is 1.5 times larger than that of PCM. Under proper operating conditions, such as loading at 77 K and 35 bar-H2, and discharging at 253 K and 2 bar-H2, PCM-Mn can achieve a usable capacity of at least 19.30 g/L. The hydrogenation kinetics curves reveal that PCM-Mn can store 1.39 wt%-H2 (8.25 g/L) under 12 MPa H2 at 298 K, while it is only 0.88 wt% (5.53 g/L) for PCM at the same condition. This work provides valuable insight into improving the hydrogen storage performance of hydrogen storage materials of physisorption.

Polynuclear Rare-Earth Cluster-Directed Self-Assembly of Highly Porous Zeolite-like Metal-Organic Frameworks with Methane Storage Property.

Due to their intrinsic structural features, the design and synthesis of a new type of zeolite-like metal-organic frameworks (ZMOFs) is highly desirable but challenging. Herein, solvothermal reactions between an angular dicarboxylate linker and rare-earth (RE) ions afforded two RE-MOFs, namely, Tb-ZMOF-2 and Tb-ZMOF-3, respectively. Structural analyses reveal that Tb-ZMOF-2 encompasses a novel [446482] cage, while Tb-ZMOF-3 contains nonanuclear (i.e., D6R) and hexanuclear (i.e., D4R) RE clusters simultaneously, subsequently resulting in two new zeolitic topologies. Thanks to its high surface area and pore volume, Tb-ZMOF-2 demonstrates considerably high gravimetric and volumetric methane storage working capacities.