Specific Pore Structure Research Articles

Co-application of biochars and Piriformospora indica improved the quality of coastal saline soil and promoted the growth of forage.

Soil quality is defined as the ability of soil to maintain the soil environment and the biosphere. Due to the limitation of salt and alkali stress, soil quality can be reduced, which in turn affects agricultural production. Biochar is widely used in saline-alkali land improvement because of its special pore structure and strong ion exchange ability, while Piriformospora indica is widely used in saline-alkali land improvement because it can symbiose with plants and improve plant stress resistance. However, the synergistic effect of combined biochar application and inoculation of P. indica on the quality of saline-alkali soil and plant development is uncertain. Hence, we investigated the combined influences of biochar and P. indica on the soil physicochemical characteristics, as well as the growth and chlorophyll florescence of sorghum-sudangrass hybrids (Sorghum bicolor × Sorghum sudane) in our study. The results indicated that after applying biochar and P. indica together, there was a considerable drop in soil pH, conductivity, Na+, and Cl- concentrations. Meanwhile, the soil organic matter (SOM), available phosphorus (AP), and alkaline hydrolyzable nitrogen (AN) increased by 151.81%, 50.84%, and 103.50%, respectively, when the Bamboo biochar was combined with 120 ml/pot of P. indica. Eventually, sorghum-sudangrass hybrid biomass, transpiration rate, and chlorophyll content increased by 111.69%, 204.98%, and 118.54%, respectively. According to our findings, using P. indica and biochar together can enhance soil quality and plant growth. The results also provide insights to enhance the quality of saline-alkali soils and the role of microorganisms in nutrient cycling.

Synergistic catalytic enhancement of chemical oxygen demand removal using Mn-Bi doped submicron fly ash carrier: Mechanistic insights and environmental adaptability

This study presents a novel approach to enhancing the removal efficiency of Chemical Oxygen Demand (COD) from water using a submicron fly ash carrier (MFA) doped with manganese (Mn) and bismuth (Bi). The synthesis process involved mechanical ball milling and alkali activation of original fly ash (FA) to obtain MFA, followed by impregnation calcination to prepare the Mn-Bi@MFA composite. The synergistic effect of Mn and Bi facilitated the formation of abundant oxygen vacancies on the catalyst surface, significantly reducing the band gap width. The Mn-Bi@MFA composite exhibited remarkable properties with a specific surface area and pore structure reaching 15.17 m2/g and 0.062 cm3/g, respectively, surpassing FA by 7.16 and 20.67 times, respectively. Utilizing the Mn-Bi@MFA/O3 system, the COD removal amount reached 562.73 mg/g under specific conditions (reaction time = 60 min, pH=7.0, catalyst dosage = 1.0 g/L, ozone dosage = 2.0 g/h), exceeding that of the ozone-alone system by 51.62 %. Moreover, Mn-Bi@MFA demonstrated excellent environmental adaptability and repeatability. An investigation into the contribution order of different free radicals revealed •OH>O2•- >1O2 in COD removal, elucidating the mechanisms of ozone oxidation, catalytic ozonation, and photocatalysis. This research provides valuable insights into the development of efficient and sustainable water treatment strategies employing advanced nano-material-based catalysts.

Tailoring microstructure and conductivity of porous hollow carbon spheres to enhance their performance as electrode materials for supercapacitors

Porous carbon materials are widely used in electrical double-layered capacitors for energy storage applications due to their abundant pores, high specific surface area and excellent electrochemical stability although their intrinsic electrical conductivity is generally low. Traditional high-temperature treatment was always adopted to boost the electrical conductivity of porous carbon materials by enhancing their graphitization degree, while this would always be accompanied by severe damage to pore structure and corresponding electrochemical performance. To solve the dilemma between boosting electrical conductivity and retaining pore structure, in this research, we proposed a low-temperature catalytic graphitization for hollow carbon spheres (HCSs) prepared by modified Stöber method accompanied with a special pore structure tailoring strategy. By altering the timing of adding carbon source, followed by secondary pore-forming and catalytic graphitization, HCSs with thin and porous shell walls along with enhanced conductivity were synthesized. Compared with the untreated HCSs or high-temperature graphitized HCSs, HCSs fabricated by the aforementioned combined strategies exhibited enhanced pore volume, specific surface area (2160.1 m2·g−1, 165.3 % of the untreated group) and conductivity (16.44±0.05 S·cm−2, 221.5 % of the untreated group), demonstrating much better electrochemical performance as the mass specific capacitance reached 256.7 F·g−1 and a volume specific capacitance reached 102.7 F·cm−3 at a current density of 1 A·g−1. Moreover, due to the largely promoted conductivity, the capacitance with the catalytic graphitized HCSs as the electrode material could be further boosted up to 273.4 F·g−1 at 1 A·g−1 by exempting the generally indispensable conductive agents and a high capacitance retention of 100.7 % was achieved after 5000 cycles at a relatively high current density of 10 A·g−1. This could be attributed to local graphitization brought by dispersed catalyst particles instead of entire atom rearrangement during high-temperature graphitization which would result in severe pore vanishing. The synergy of low-temperature catalytic graphitization and secondary pore-forming might be a novel strategy in electrode material fabrication for advanced supercapacitors or other energy storage devices.

Methane adsorption effect of cyclodextrin-based metal-organic frameworks and ultra-fine water mist composite system in closed container

Natural gas, predominantly composed of methane, is a widely used energy source. Methane is prone to leakage during storage and usage, posing environmental risks. Currently, effective strategies to capture methane leaked in urban environments are lacking. This study investigates the synthesis of a non-toxic Cyclodextrin-based Metal-Organic Framework (CD-MOF) and its adsorption capacity for leaked methane in an ultrafine water mist composite solution system. CD-MOFs, utilizing β-cyclodextrin as the organic ligand and alkali metal potassium as the metal ion, were synthesized via solvothermal and methanol vapor diffusion method. The morphology, functional groups, and thermal properties of CD-MOFs were characterized by multiple techniques. The BET specific surface area, pore structure, and high-pressure methane adsorption capacity of the samples were investigated. Furthermore, CD-MOF, surfactant, and castor oil were combined to create a composite solution absorbent. The methane absorption efficacy of this ultra-fine water mist of absorbent was tested using a closed-container methane spray adsorption apparatus, and the compound solution ratio was optimized. The results indicate that CD-MOFs retain the parent cyclodextrin structure, and the methane adsorption capacity under high-pressure (35 bar) of CD-MOF synthesized by the sodium dodecyl sulfate-assisted solvothermal method reached 216.13 cm3/g. The composite solution with an appropriate proportion of surfactant, castor oil, and CD-MOF reached a methane absorption capacity of 5.7 % vol in enclosed spaces. The successful synthesis of CD-MOFs and the application of composite solutions with ultra-fine water mist offer innovative approaches and theoretical guidance for the emergency absorption and non-toxic disposal of leaked methane.

Artificial Intelligence and High-Throughput Computational Workflows Empowering the Fast Screening of Metal-Organic Frameworks for Hydrogen Storage.

Metal-organic frameworks (MOFs) are one of the most promising hydrogen-storing materials due to their rich specific surface area, adjustable topological and pore structures, and modified functional groups. In this work, we developed automatically parallel computational workflows for high-throughput screening of ∼11,600 MOFs from the CoRE database and discovered 69 top-performing MOF candidates with work capacity greater than 1.00 wt % at 298.5 K and a pressure swing between 100 and 0.1 bar, which is at least twice that of MOF-5. In particular, ZITRUP, OQFAJ01, WANHOL, and VATYIZ showed excellent hydrogen storage performance of 4.48, 3.16, 2.19, and 2.16 wt %. We specifically analyzed the relationship between pore-limiting diameter, largest cavity diameter, void fraction, open metal sites, metal elements or nonmetallic atomic elements, and deliverable capacity and found that not only geometrical and physical features of crystalline but also chemical properties of adsorbate sites determined the H2 storage capacity of MOFs at room temperature. It is highlighted that we first proposed the modified crystal graph convolutional neural networks by incorporating the obtained geometrical and physical features into the convolutional high-dimensional feature vectors of period crystal structures for predicting H2 storage performance, which can improve the prediction accuracy of the neural network from the former mean absolute error (MAE) of 0.064 wt % to the current MAE of 0.047 wt % and shorten the consuming time to about 10-4 times of high-throughput computational screening. This work opens a new avenue toward high-throughput screening of MOFs for H2 adsorption capacity, which can be extended for the screening and discovery of other functional materials.

Enhanced sorption and destruction of PFAS by biochar-enabled advanced reduction process

The biochar-enabled advanced reduction process (ARP) was developed for enhanced sorption (by biochar) and destruction of PFAS (by ARP) in water. First, the biochar (BC) was functionalized by iron oxide (Fe3O4), zero valent iron (ZVI), and chitosan (chi) to produce four biochars (BC, Fe3O4-BC, ZVI-chi-BC, and chi-BC) with improved physicochemical properties (e.g., specific surface area, pore structure, hydrophobicity, and surface functional groups). Batch sorption experimental results revealed that compared to unmodified biochar, all modified biochars showed greater sorption efficiency, and the chi-BC performed the best for PFAS sorption. The chi-BC was then selected to facilitate reductive destruction and defluorination of PFAS in water by ARP in the UV-sulfite system. Adding chi-BC in UV-sulfite ARP system significantly enhanced both degradation and defluorination efficiencies of PFAS (up to ∼100% degradation and ∼85% defluorination efficiencies). Radical analysis using electron paramagnetic resonance (EPR) spectroscopy showed that sulfite radicals dominated at neutral pH (7.0), while hydrated electrons (eaq–) were abundant at higher pH (11) for the efficient destruction of PFAS in the ARP system. Our findings elucidate the synergies of biochar and ARP in enhancing PFAS sorption and degradation, providing new insights into PFAS reductive destruction and defluorination by different reducing radical species at varying pH conditions.

Soft template-induced self-assembly strategy for sustainable production of porous carbon spheres as anode towards advanced sodium-ion batteries

Doped porous carbon is a prominent sodium anode material with high specific surface area (SSA) and abundant pore structure. Compared with the traditional “hard template” technique for the synthesis of porous carbon, the “soft template” method offers a more efficient synthesis process and simplified template removal. In response to the urgent need for eco-friendly synthesis methods for functional doping, our research introduces an innovative method using biomass-derived tannic acid as a precursor. We have successfully synthesized N/S double-doped porous spherical carbon materials (DF-N/S) through a self-assembly process driven by hydrogen bonding and solvent evaporation. As an anode material for sodium-ion batteries (SIBs), DF-N/S demonstrates superior electrochemical performance, achieving a specific capacity of 327.04 mAh g−1 at a current density of 0.05 Ag-1 in ether-based electrolytes. The remarkable sodium storage efficiency of DF-N/S has been thoroughly examined through kinetic analyses and ex-situ characterization methods. This study aims to provide a sustainable and widely adaptable method for the soft template production of doped carbon, while also shedding light on the intricacies of energy storage mechanisms in both ether/ester-based electrolytes.

Research Progress on Controllable Absorption Properties of Rare Earth Element Doped Electromagnetic Wave Absorbing Materials†

Comprehensive SummaryThe utilization of rare earth (RE) elements is pivotal in wave absorption. In particular cases, RE group elements manifesting unique 4f electron layer structures are doped as impurities into certain materials, which is a practical and reliable method for regulating these materials' magnetic and electrical properties. Moreover, ferrites and metal‐organic frameworks (MOFs), standing out among conventional and emerging wave‐absorbing materials, can achieve significantly enhanced wave absorption through RE doping or substitution. Numerous scholars have dedicated massive research over a substantially long time to explore the utilization of RE elements to reinforce the absorption of these two materials. Therefore, consolidating and summarizing such efforts are crucial and necessary. This review aims to clarify the underlined mechanism of electromagnetic wave (EMW) absorption and elaborate on the impact of RE doping by providing a comprehensive overview of recent progress in ferrites and MOFs dopped with RE elements. Finally, the limitations associated with RE doping in such materials are delineated, and the upcoming prospects for its application are highlighted. Key ScientistsIn 1947, J. A. Marinky et al. obtained promethium from uranium fission products. From the isolates of yttrium soil in 1794 to the discovery of promethium in 1947, it took more than 150 years. In 1975, Guangxian Xu found that the rare earth solvent extraction system has the basic "constant mixed extraction ratio" rule. In 1984, the theory of "one‐cavity multi‐mode" was proposed by Weigan Lin to improve the electromagnetic wave theory further and develop the theory of absorbing materials. In 1995, Omar M. Yaghi synthesized the first MOFs in history, and since then, they have been widely used in gas adsorption and separation and other fields because of their large specific surface area and adjustable pore structure. In recent years, various functional materials based on MOFS‐derived carbon have been studied endlessly. Masato Sagawa, known for inventing NdFeB magnets, won the "28th Japan Prize" in 2012. In recent years, Renchao Che has promoted the development of interface theory and magnetic theory in the field of wave absorption. In addition, Jiurong Liu is committed to developing various wave‐absorbing materials and the respective theoretical research and continues to promote the development of wave‐absorbing materials to "thin, light, wide and strong".

Corn-inspired high-density plasmonic metal-organic frameworks microneedles for enhanced SERS detection of acetaminophen

Effective monitoring of acetaminophen (APAP) dosage is crucial for preventing antipyretic abuse, ensuring therapeutic efficacy, and minimizing toxic effects. However, existing self-monitoring methods are limited. In this study, we designed a plasmonic microneedle (MN) sensor for real-time nondestructive monitoring of acetaminophen levels in dermal interstitial fluid (ISF) by employing a handheld Raman spectrometer. The fabricated MN sensor incorporated a high-density plasmonic MOFs known as HDPM, which unique structure of large specific surface area, specific pore structure as well as high density gold nanospheres packing enabled the excellent performance of selective ISF drug enrichment and surface-enhanced Raman scattering (SERS). The maximum electric field enhancement factor of the HDPM nanostructure could be calculated as 5.73 × 107. The developed HDPM@MNs was characterized with a core-shell type “soft on the outside and rigid on the inside” structure, which exhibited sufficient hardness and flexibility to penetrate the dermal tissue with little damage, and robust SERS enhancement effect in APAP detection without any interfering peaks. Through a hydrogel drug simulation experiment, the sensor demonstrated robust capabilities for acetaminophen enrichment and monitoring, exhibiting excellent stability and repeatability. The quantitative detection window spanned from 1 to 100 μM, with a low detection limit reaching 0.45 μM. Furthermore, by monitoring the concentration of acetaminophen in the interstitial fluid of rat skin at different doses and for different administration times, the HDPM@MNs can be used to determine the pharmacokinetics of acetaminophen in rats and the physiological characteristics associated with various dosage regimens. This work not only holds promise for drug monitoring but also provides a novel approach for nondestructive monitoring of other crucial low-abundance physiological markers.

MOF‐Derived Porous Carbon for Zinc‐ion Hybrid Capacitors with Ultra‐High Energy Density and Long Cycling Life

AbstractZinc‐ion hybrid capacitors (ZHC) have been considered as emerging sustainable electrochemical energy storage devices. They integrate the benefits of high‐energy density of aqueous zinc ion battery (ZIB) with high‐power density of supercapacitor (SC). Metal‐organic frameworks (MOFs) have been widely used to design electrode materials for portable devices, especially in some energy storage fields because of their large specific surface area and adjustable pore structures. In this work, we prepare porous Mn3O4/C nanosheets with Mn‐BDC as a precursor. The assembled device delivers a specific capacitance of 155.3 mAh g−1 at a current of 3 A g−1 and keeps a retention rate of 97.7 % after 10,000 cycles. Moreover, it provides an energy density of 464.5 Wh kg−l at a power density of 100 W kg−1.

Degradation of Sodium Acetate by Catalytic Ozonation Coupled with MnOx/NiOOH-Modified Fly Ash.

Fly ash, a type of solid waste generated in power plants, can be utilized as a catalyst carrier to enhance its value-added potential. Common methods often involve using a large amount of alkali for preprocessing, resulting in stable quartz and mullite forming silicate dissolution. This leads to an increased specific surface area and pore structure. In this study, we produced a catalyst composed of MnOx/NiOOH supported on fly ash by directly employing nickel hydroxide and potassium permanganate to generate metal active sites over the fly ash surface while simultaneously creating a larger specific surface area and pore structure. The ozone catalytic oxidation performance of this catalyst was evaluated using sodium acetate as the target organic matter. The experimental results demonstrated that an optimal removal efficiency of 57.5% for sodium acetate was achieved, surpassing even that of MnOx/NiOOH supported catalyst by using γ-Al2O3. After loading of MnOx/NiOOH, an oxygen vacancy is formed on the surface of fly ash, which plays an indirect oxidation effect on sodium acetate due to the transformation of ozone to •O2- and •OH over this oxygen vacancy. The reaction process parameters, including varying concentrations of ozone, sodium acetate, and catalyst dosage, as well as pH value and the quantitative analysis of formed free radicals, were examined in detail. This work demonstrated that fly ash could be used as a viable catalytic material for wastewater treatment and provided a new solution to the added value of fly ash.

Design of double‐core‐shell structural materials for the extraction of non‐steroidal anti‐inflammatory drugs

In this work, core‐shell material with a special structure was designed and applied in solid‐phase extraction (SPE) for non‐steroidal anti‐inflammatory drugs (NSAIDs) combined with high‐performance liquid chromatography. Based on the advantages of core‐shell ZIF‐8@ZIF‐67 (Zeolite imidazole ester framework materials [ZIFs]), effective derivatization treatment was carried out to partially vulcanize the original ZIFs, resulting in a special and new double‐core‐shell structural material CoS/ZIF‐67/ZnS/ZIF‐8 (ZIFs@ZnS@CoS) with porous surface and center hollow. The multiple forces caused by the rich chemical structure, the large specific surface area caused by the special pore structure, and the effective protection of the ZIFs core by sulfide shell make the designed material have higher extraction efficiency and longer service life, compared with ZIF‐8@ZIF‐67 and ZIF‐8. At the same time, the established analytical method for non‐steroidal drugs had a high recovery rate (98.93%–102.10%), low detection limit (0.11–0.27 µg/L), and wide linear range (1–200 µg/L) within a good correlation coefficient R2 (0.9978–0.9993). Satisfactory results were also obtained from the extraction of NSAIDs from the Yellow River water samples. These results indicate that the designed double‐core‐shell structure material can effectively exert its structural advantages and become a promising extraction material.

Enhancement of nitric oxide reduction via CeZrOx/Cu‐SSZ‐39 hybrid catalyst: Improving activity and hydrothermal stability

AbstractThis study aimed to improve the catalytic activity and hydrothermal stability of Cu‐SSZ‐39 zeolite by coupling it with cerium zirconium oxides (CeZrOx), which possesses excellent oxidizing ability, and a hybrid catalyst CeZrOx/Cu‐SSZ‐39 was prepared. It is found that it exhibited enhanced low‐temperature activity, high‐temperature activity, and a wider effective temperature range compared to Cu‐SSZ‐39. Characterization results showed that the CeZrOx/Cu‐SSZ‐39 catalyst had a higher concentration of active Cu2+ ion species and improved redox properties, which could potentially promote the NH3‐SCR reaction. Additionally, the CeZrOx/Cu‐SSZ‐39 catalyst had increased chemisorbed oxygen species on its surface, facilitating the oxidation of NO to NO2 and enhancing the rate of the SCR reaction. Moreover, even after undergoing hydrothermal aging treatment, the CeZrOx/Cu‐SSZ‐39 catalyst exhibited superior catalytic activity and improved hydrothermal stability, surpassing the performance of Cu‐SSZ‐39. It is found the CeZrOx coupling allowed the hybrid catalyst to maintain a better specific surface area and pore structure during hydrothermal aging, resulting in reduced activity loss. Therefore, the addition of CeZrOx enhanced the NH3‐SCR activity of Cu‐SSZ‐39 zeolite, leading to improved catalytic activity and hydrothermal stability. CeZrOx/Cu‐SSZ‐39 catalyst has shown promising aspect for reducing NOx emissions from diesel vehicle exhaust.

Two‐Dimensional Conjugated Metal–Organic Frameworks with a Ring‐in‐Ring Topology and High Electrical Conductance

AbstractElectrically conducting two‐dimensional (2D) metal–organic frameworks (MOFs) have garnered significant interest due to their remarkable structural tunability and outstanding electrical properties. However, the design and synthesis of high‐performance materials face challenges due to the limited availability of specific ligands and pore structures. In this study, we have employed a novel highly branched D3h symmetrical planar conjugated ligand, dodechydroxylhexabenzotrinaphthylene (DHHBTN) to fabricate a series of 2D conductive MOFs, named M–DHHBTN (M=Co, Ni, and Cu). This new family of MOFs offers two distinct types of pores, elevating the structural complexity of 2D conductive MOFs to a more advanced level. The intricate tessellation patterns of the M–DHHBTN are elucidated through comprehensive analyses involving powder X‐ray diffraction, theoretical simulations, and high‐resolution transmission electron microscope. Optical‐pump terahertz‐probe spectroscopic measurements unveiled carrier mobility in DHHBTN‐based 2D MOFs spanning from 0.69 to 3.10 cm2 V−1 s−1. Among M–DHHBTN famility, Cu‐DHHBTN displayed high electrical conductivity reaching 0.21 S cm−1 at 298 K with thermal activation behavior. This work leverages the “branched conjugation” of the ligand to encode heteroporosity into highly conductive 2D MOFs, underscoring the significant potential of heterogeneous double‐pore structures for future applications.

Two-Dimensional Conjugated Metal-Organic Frameworks with a Ring-in-Ring Topology and High Electrical Conductance.

Electrically conducting two-dimensional (2D) metal-organic frameworks (MOFs) have garnered significant interest due to their remarkable structural tunability and outstanding electrical properties. However, the design and synthesis of high-performance materials face challenges due to the limited availability of specific ligands and pore structures. In this study, we have employed a novel highly branched D3h symmetrical planar conjugated ligand, dodechydroxylhexabenzotrinaphthylene (DHHBTN) to fabricate a series of 2D conductive MOFs, named M-DHHBTN (M=Co, Ni, and Cu). This new family of MOFs offers two distinct types of pores, elevating the structural complexity of 2D conductive MOFs to a more advanced level. The intricate tessellation patterns of the M-DHHBTN are elucidated through comprehensive analyses involving powder X-ray diffraction, theoretical simulations, and high-resolution transmission electron microscope. Optical-pump terahertz-probe spectroscopic measurements unveiled carrier mobility in DHHBTN-based 2D MOFs spanning from 0.69 to 3.10 cm2 V-1 s-1. Among M-DHHBTN famility, Cu-DHHBTN displayed high electrical conductivity reaching 0.21 S cm-1 at 298 K with thermal activation behavior. This work leverages the "branched conjugation" of the ligand to encode heteroporosity into highly conductive 2D MOFs, underscoring the significant potential of heterogeneous double-pore structures for future applications.

Treatment of phenolic wastewater in an anaerobic fluidized bed microbial fuel cell filled with graphene oxide-macroporous adsorption resin as multifunctional carrier

ABSTRACT A novel graphene oxide-modified resin (graphene oxide-macroporous adsorption resin) was prepared and used as a multifunctional carrier in an anaerobic fluidized bed microbial fuel cell (AFB-MFC) to treat phenolic wastewater (PW). The macroporous adsorption resin (MAR) was used as the carrier, graphene oxide was used as the modified material, the conductive modified resin was prepared by loading graphene oxide (GO) on the resin through chemical reduction. The modified resin particles were characterized by scanning electron microscopy (SEM), Raman spectroscopy (RS), specific surface area and pore structure analysis. Graphene oxide-macroporous adsorption resin special model was established using the Amorphous Cell module in Materials Studio (MS), and the formation mechanism of graphene oxide-macroporous adsorption resin was studied using mean square displacement (MSD) of the force module. Molecular dynamics simulation was used to study the motion law of molecular and atomic dynamics at the interface of graphene oxide-macroporous adsorption resin composites. The strong covalent bond between GO and MAR ensures the stability of GO/MAR. When the modified resin prepared in 3.0 mg/mL GO mixture was used in the AFB-MFC, the COD removal of wastewater was increased by 9.1% to 72.44%, the voltage was increased by 84.04% to 405.8 mV, and power density was increased by 765.44% to 242.67 mW/m2.

Imidazole-based organic polymer frameworks as metal- and halogen-free heterogeneous platforms for efficient CO2 cycloaddition

Developing effective metal- and halogen-free heterogeneous catalysts for the CO2 cycloaddition remains a challenge. In this study, novel imidazole-based hyper-crosslinked polymers (HCP-BZ, HCP-BP and HCP-TBZ) with abundant N sites were constructed via a one-pot polymerization, and employed as heterogeneous catalysts for the CO2 cycloaddition reaction. The special skeletal pore structure with abundant hierarchical pore structures and uniformly distributed active sites were demonstrated by various characterization technologies. The optimal HCP-TBZ(16:1) exhibits a good CO2 selective adsorption performance with a CO2 adsorption capacity of 2.23 mmol/g and CO2/N2 adsorption selectivity of 41 at 273 K and 0.1 MPa. Additionally, the resulting catalyst HCP-TBZ(16:1) achieves an excellent catalytic performance with 96 % yield and 99 % selectivity without metal, halogen, cocatalyst and solvent additions (120 °C, 1.0 MPa CO2, 5 h). Moreover, the HCP-TBZ(16:1) also exhibits a satisfactory catalytic activity under the mild conditions (70 °C, 1.0 MPa CO2), and can effectively catalyze the cyclic carbonate preparation from the dilute CO2 (15 %CO2/85 %N2). The comparable catalytic activity and the determined structural stability, reusability and universality make the prepared imidazole-based HCPs a potential heterogeneous catalyst candidate for the CO2 cycloaddition. This study will provide some guidance for developing metal-free and halogen-free CO2 adsorption and conversion platforms.

Nickle ion surface engineered MOF derived α-Fe2O3 octahedrons for high efficiency toluene detection with high moisture resistance and long-term stability

Metal-organic framework derivatives have become very promising candidates for gas sensors due to their advantages of large specific surface area, many surface active sites, and tunable properties. Meanwhile, Ni ion doping is an effective technique to enhance the moisture resistance of sensing materials. Inspired by this, in this work, we have successfully synthesized porous octahedral structures of Ni-Fe2O3 derived from metal-organic frameworks by in situ doping, in which the Ni contents were 0.4, 0.5 and 0.6 mol%, respectively. Notably, Ni doping changes the conductive type of Fe2O3 from n-type to p-type with a significant decrease in resistance. At the same time, the sensing performance of Fe2O3 octahedrons for volatile organic compound gases, especially toluene, is greatly improved. The 0.5 mol% Ni doped Fe2O3 sensor showed the highest response to toluene at 225°C (100 ppm, 47), which is five times higher than the pristine Fe2O3 (response 9.5). In addition, the sensor demonstrated fast response and recovery time (20 s/40 s), low detection limit (200 ppb), high moisture tolerance (98% RH, 47), and long-term stability of over 60 days. The main reason for the exceptional performance of Ni doped Fe2O3 sensors is its special porous octahedral structure, and more importantly, the change of carrier type of the sensing material after Ni doping and the substantial increase of oxygen vacancies, and the catalytic effect of Ni ions.

Confined growth of Ultrathin, nanometer-sized FeOOH/CoP heterojunction nanosheet arrays as efficient self-supported electrode for oxygen evolution reaction

Self-supported electrodes, featuring abundant active species and rapid mass transfer, are promising for practical applications in water electrolysis. However, constructing efficient self-supported electrodes with a strong affinity between the catalytic components and the substrate is of great challenge. In this study, by combining the ideas of in-situ construction and space-confined growth, we designed a novel self-supported FeOOH/cobalt phosphide (CoP) heterojunctions grown on a carefully modified commercial Ni foam (NF) with three-dimensional (3D) hierarchically porous Ni skeleton (FeOOH/CoP/3D NF). The specific porous structure of 3D NF directs the confined growth of FeOOH/CoP catalyst into ultra-thin and small-sized nanosheet arrays with abundant edge active sites. The active FeOOH/CoP component is stably anchored on the rough pore wall of 3D NF support, leading to superior stability and improved conductivity. These structural advantages contributed to a highly facilitated oxygen evolution reaction (OER) activity and enhanced durability of the FeOOH/CoP/3D NF electrode. Herein, the FeOOH/CoP/3D NF electrode afforded a low overpotential of 234 mV at 10 mA cm−2 (41 mV smaller than FeOOH/CoP grown on unmodified Ni foam) and high stability for over 90 h, which is among the top reported OER catalysts. Our study provides an effective idea and technique for the construction of active and robust self-supported electrodes for water electrolysis.

Optimizing alkali metal Salt-Induced structural assembly of Ni-MgO dual function materials for enhanced CO2 capture and methanation performance

Alkali metal salts (AMS) promoted Ni-MgO dual function materials (DFMs) show exhibit potential in integrated CO2 capture and methanation. However, the CO2 adsorption and methanation efficiency of these materials is contingent upon their adsorptive and catalytic sites, which are significantly susceptible to the incorporated AMS. Herein, we investigate the effect of assemble configuration of AMS and Ni on the structural properties and integrated CO2 capture and methanation performance of the AMS-promoted Ni-MgO DFMs. By preferentially incorporating AMS to form the Ni-AMS-MgO configuration, AMS is allocated throughout both the internal core and external layer of MgO particles. Given AMS's preferential occupation of specific pore structures, Ni is evenly distributed as smaller particles on the MgO surface, minimally influenced by the carbonate formed during adsorption. The Ni-AMS-MgO configuration demonstrates superior integrated CO2 capture and methanation performance, featuring high CO2 uptake (1.86 mmol/g) and CH4 yield (1.37 mmol/g).