Super High Specific Surface Area Research Articles

Synthesis of mesoporous MIL-100(Fe) from acid mine drainage sludge for norfloxacin removal: Industrial sludge high value utilization, adsorbent performance and contaminant removal mechanisms

Recovery of heavy metals from acid mine drainage sludge (AMDs) and their conversion into high value-added materials such as metal-organic frameworks (MOFs) is of great significance for sustainable development. MOFs have broad application prospects in liquid phase pollutant removal, owing to super high specific surface area and adjustable structure. In this study, MIL-100(Fe) with mesoporous structures was successfully prepared from AMDs by acid leaching-hydrothermal method. And the obtained MIL-100(Fe) was employed as an adsorbent for adsorptive norfloxacin (NOR) removal from wastewater. The adsorption results showed that the maximum adsorption capacity can reach 280.84 mg/g under the condition of 298 K, the initial pH value of solution is 10 and the dosage of catalyst is 0.1 g/L. According to the N2 sorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) characterization, the adsorption mechanism of NOR on MIL-100(Fe) is mainly attributed to electrostatic interaction, π-π stacking, pore filling and coordination. Furthermore, the adsorbent maintained 75.05% of its initial adsorption capacity after 5 cycles, indicating that MIL-100(Fe) has excellent stability. This study provides a new idea for the resource utilization of industrial sludge.

Synthesis of novel graphene-based targeted hydrogen getter nanocomposites and their properties

The getter setting is critical for maintaining a high vacuum environment in the annular space of multilayer insulation in the cryogenic vessel. To maximize the sorption of residual gases, particularly hydrogen, an efficient targeted hydrogen getter must be designed. In this study, PdO nanoparticles and Alkyne-PVA were loaded onto graphene oxide to create an efficient and cost-effective targeted hydrogen getter. Raman, XRD, XPS, SEM, TEM, and other characterization methods were used to investigate the microstructure and morphology of the intermediate and Alkyne-PVA-(GO-PdO) nanocomposites. The “Getter Sorption Properties Test System” was used to evaluate the hydrogen sorption properties of the nanocomposites. The results show that the super high specific surface area and efficient network structure of GO can be used as a good substrate material for the loading of PdO nanoparticles and Alkyne-PVA, and that the nanocomposites prepared with reasonable ratios of PdO nanoparticles and Alkyne-PVA have excellent hydrogen sorption performance, and have promising application prospects. The simultaneous use of unsaturated hydrocarbon branched chain and Pd element to the construction of a low-temperature vacuum annular space hydrogen getter in this work is critical to the commercial popularization of hydrogen getters.

Preparation of macadamia nut shell porous carbon and its electrochemical performance as cathode material for lithium–sulfur batteries

Biomass carbon material as the sulfur storage matrix of lithium–sulfur batteries is one of the research hotspots. In this paper, the macadamia nut shells are used as the precursor to prepare porous carbon material. By exploring the effect of temperature on the microstructure and electrochemical performance of porous carbon materials during activation, it is found that the porous carbon material prepared under the activation condition of 900 °C has a developed pore structure, super high specific surface area (3552.7 m2•g−1), larger pore volume (2.2 cm3•g−1) and higher mesoporous content (23.85%). And the composite cathode material with the sulfur content of 70.1% has the highest specific capacity, and the initial discharge specific capacity for 0.2 C can reach 942.4 mAh•g−1. The composite material S/OCNT@OPC-1:1 obtained by compounding it with carbon nanotubes at a mass ratio of 1:1 has higher specific capacity, better rate performance and cycle performance. At 0.2 C, the initial discharge specific capacity is as high as 1252.6 mAh•g−1, and it remains at the level of 717.3 mAh•g−1 after 200 cycles. Even at 1 C, the specific capacity is still 984.3 mAh•g−1, and it remains at 690.9 mAh•g−1 after 200 cycles, and the capacity retention rate is 70.2%. Our work shows that the composite material obtained by combining low-cost biomass carbon materials and carbon nanotubes as the cathode material for lithium-sulfur batteries has obvious advantages.

Facile fabrication of phenylenediamine residue derived N, O co-doped hierarchical hyperporous carbon for high-efficient chloroxylenol removal

• Hierarchical hyperporous carbon (HHPC) was derived from phenylenediamine residue. • One-step “carbonization-casting-activation” strategy was used for HHPC synthesis. • The HHPC shows superior chloroxylenol adsorption capacity. • In-situ N/O co-dopped carbon surface enhances the adsorption of chloroxylenol. The chloroxylenol (PCMX) has shown well virucidal efficacy against COVID-19, but the large-scale utilization of which will undoubtedly pose extra environmental threaten. In the present study, the recycled industrial phenylenediamine residue was used and an integrated strategy of “carbonization-casting-activation” using super low-dose of activator and templates was established to achieve in-situ N/O co-doping and facile synthesis of a kind of hierarchical hyperporous carbons (HHPC). The sample of HHPC-1.25–0.5 obtained with activator and template to residue of 1.25 and 0.5 respectively shows super-high specific surface area of 3602 m 2 /g and volume of 2.81 cm 3 /g and demonstrates remarkable adsorption capacity of 1475 mg/g for PCMX in batch and of 1148 mg/g in dynamic column adsorption test. In addition, the HHPC-1.25–0.5 exhibits excellent reusability and tolerance for PCMX adsorption under various ionic backgrounds and real water matrix conditions. The combined physio-chemistry characterization, kinetic study and DFT calculation reveal that the enhanced high performances originate from the hierarchical pore structure and strong electrostatic interaction between PCMX and surface rich pyridinic-N and carbonyl groups.

Ultra-high specific capacitance of self-doped 3D hierarchical porous turtle shell-derived activated carbon for high-performance supercapacitors

The turtle shell of biomass waste is used as raw material, and the natural inorganic salt contained in it is used as a salt template in combination with a chemical activation method to successfully prepare a high-performance activated carbon with hierarchical porous structure. The role of hydroxyapatite (HAP) and KOH in different stages of preparation was investigated. The prepared turtle shell-derived activated carbon (TSHC-5) has a well-developed honeycomb pore structure, which gives it a high specific surface area (SSA) of 2828 m 2 g −1 with a pore volume of 1.91 cm 3 g −1 . The excellent hierarchical porous structure and high heteroatom content (O 6.88%, N 5.64%) allow it to have an ultra-high specific capacitance of 727.9 F g −1 at 0.5 A g −1 with 92.27% of capacitance retention even after 10,000 cycles. Excitingly, the symmetric supercapacitor assembled from TSHC-5 activated carbon exhibits excellent energy density and cycling stability in a 1 M Na 2 SO 4 aqueous solution. The energy density is 45.1 Wh·kg −1 at a power density of 450 W kg −1 , with 92.05% capacitance retention after 10,000 cycles. Therefore, turtle shell-derived activated carbon is extremely competitive in sustainable new green supercapacitor electrode materials. • Grass turtle shell contains heteroatoms and HAP for self-doping and as self-templates, respectively. • TSHC-5 has hierarchical porous structure with super high SSA (2828 m 2 g −1 ) and pore volume (1.91 cm 3 g −1 ). • Heteroatoms (O 6.88%, N 5.64%) can improve the wettability and conductivity of electrode materials. • TSHC-5 exhibits an ultra-high specific capacitance of 727.9 F g −1 at 0.5 A g −1 . • The energy density of supercapacitor is 45.1 Wh·kg −1 at 450 W kg −1 using 1 M Na 2 SO 4 as electrolyte.

Fabrication of a durable coral-like superhydrophilic MgO coating on stainless steel mesh for efficient oil/water separation

A superhydrophilic/underwater superoleophobic MgO&SSM coating on SSM (stainless steel mesh) with micro-nano coral-like structure was fabricated by high-temperature treatment of SSM soaked with magnesium nitrate solution. This unique coral-like structure gives it a super high specific surface area and a large number of hydroxyl groups are exposed to the surface. The oil–water separation efficiency achieved 99.0% and the flux attained to 6195 L·m−2 h−1. And the oil–water separation efficiency was always as high as 98.0% after 10 times of repeated use. In addition, it could still maintain underwater superoleophobicity after immersing them in different pH solutions (pH, 5–12) or saturated NaCl solutions for a certain period of time. More importantly, it still maintained underwater superoleophobicity and shown excellent weather resistance after being treated at different temperatures for 2 h or after being exposed to ultraviolet rays at elevated temperatures for 6 h.

Microcrystalline cellulose derived hierarchically porous nanocarbons via a template-free method for high performance supercapacitors

The efficient and low-cost method to produce sustainable energy materials for supercapacitor is highly sought after. Biomass offers great opportunities as green and low-cost raw materials; however, the extra activation and multi-step procedures to obtain desirable porosity are often required. Herein, a simple and economy way was developed to synthesized hierarchically porous nanocarbons with N-doping. Microcrystalline cellulose was chosen as the carbon precursor and thermally treated in N2, NH3, and CO2 atmospheres in tandem. This continuous gas treatment enables the formation of functional carbons with high surface area and abundant porosity. The optimized pyrolytic carbon HPNC-150 expresses a super high specific surface area reaching up to 3278 m2 g-1 with the pore volume of 1.6291 cm3 g−1. Electrochemical tests indicate the carbon HPNC-150 delivers a specific capacitance of 221 F g−1 at a current density of 1 A g−1 and remains 201 F g−1 at 5 A g−1, and thus show an excellent storage capacity for supercapacitor applications. Besides, it was found that the competition between the thermal graphitization and CO2 activation balances the hierarchical porosity and electrical conductivity, which is a good reference to synthesize the porous conductive substrates for further modifications.

A primary understanding of field emission from superhigh specific surface area activated carbon with interconnection structure

In this study, activated carbon (AC) with the specific surface area up to 3152 m2 g−1 is synthetized and structural-characterized. The AC powder displays the interconnective framework structure composed of numerous carbon nanosheets and the sharp edges act as the active sites to achieve efficient electron emission. The screen-printed AC cold cathode shows large emission current density of 15 mA cm−2 under relatively low electrical field of 6.0 V μm−1, with stable emission of up to 280 min. In conjunction to its uniform emission pattern, robustness, and vacuum-compatibility test, the feasibility of AC cold cathode in field emission devices have been demonstrated. This work provides a primary understanding of field emission performance for the AC electron emitter and expands the application fields of superhigh specific surface area AC.

Mechanism of transition metal cluster catalysts for hydrogen evolution reaction

Studying the hydrogen evolution reaction (HER) catalyst is important for the global energy crisis. Clusters have many special characteristics due to quantum size effect and super high specific surface area, including optical performance, catalytic performance, etc. In this work, the structures of transition metal cluster TMn (TM = Co, Ni, Cu, Pd, Pt, n = 4–10) were searched and optimized by quantum chemistry methods. To search for non-precious metal catalysts, we calculated the Gibbs free energies for HER process on different clusters. Furthermore, the electronic structures of clusters before and after the reaction with H were analyzed, including the molecular surface electron distribution, the frontier molecular orbital, and the charge transfer properties, which dominated the HER processes. The results show that the Cu clusters have excellent HER catalytic properties due to its suitable surface electron distribution and HOMO/LUMO levels, especially Cu4, Cu7 and Cu9, which even comparable to Pt catalysts. These results can help us better understand the mechanism of clusters catalyze HER process.

Hierarchical porous activated graphene nanosheets with an ultra-high potential as electrode material for symmetric supercapacitors

Activated graphene nanosheets (AGNs) are fabricated from graphene nanosheets (GNSs) by the facile KOH activation process. It displays that the obtained AGNs have a hierarchical porous structure, leading to the superhigh specific surface area of 2662 m2 g−1. The obtained AGNs electrode exhibited high specific capacitance (238 F g−1 at 1 A g−1) and remarkable rate performance (79.41% at 10 A g−1), exhibiting higher rate performance than reported carbon materials. Furthermore, the AGNs also show exceptional cycling capacity (99% after 20,000 cycles at 5 A g−1) in 1.0 M TEA BF4/AN electrolyte with an ultra-high potential range from 0 to 3.5 V. The symmetric supercapacitor displays a high energy density of 42.78 Wh kg−1 at a power density of 2071 W kg−1 and excellent cycle stability. The superior electrochemical performance can be attributed to the high specific surface area that has a larger contact area with the electrolyte, and the porous structure which provides a richer ion transport channel.

Microwave-assisted KOH activation from lignin into hierarchically porous carbon with super high specific surface area by utilizing the dual roles of inorganic salts: Microwave absorber and porogen

Searching an appropriate biomass that is capable of absorbing microwave energy is significant to realize its rapid microwave-assisted conversion into porous carbons (PCs). Herein, the lignin derived from waste pulping black liquor via crude extraction is directly converted into high-performance PC for a very short duration of 10–30 min by microwave heating. The inherent inorganic salts in crude lignin with a high content of 17.3% is innovatively used as initial microwave absorber to achieve rapid conversion from lignin into bio-char, and further as porogen combined with KOH to synergistically obtain well-developed porous texture. The resultant PC possesses a super high specific surface area of 3065 m 2 g −1 , hierarchical pore size distribution with abundant micropores (0.73 cm 3 g −1 ) and a remarkable meso-/macropores ratio of 64.4%, highly disordered and amorphous structure, as well as oxygen-enriched structure with a surface oxygen content up to 16.5%. These attractive characteristics contribute to excellent electrochemical properties of the resultant supercapacitor electrode which exhibits a high specific capacitance of 325 F g −1 at 0.5 A g −1 in 6 mol L −1 KOH electrolyte, still maintaining a high value of 258 F g −1 (79.4%) at 50 A g −1 . The prepared supercapacitor can remain 81.9% energy density when the power density was increased by 20 folds, suggesting its excellent energy-power synergetic outputting property. These attractive results pave a new way to utilize such a biomass waste, especially with high inorganic salts content, into value-added electrode material for advanced energy storage application. • Conversion from waste lignin into porous carbon only required 10–30 min. • Inorganic salts act as microwave absorber and also porogen. • Super high specific surface areas surpassing 3000 m 2 g −1 were achieved. • A remarkably high rate capability of 79.4% was achieved at 50 A g −1 .

Multifunctional hierarchical mesoporous silica and black phosphorus nanohybrids as chemo-photothermal synergistic agents for enhanced cancer therapy.

Synergistic therapy with high efficacy and low side effects is of great significance in cancer treatment, and therefore the elaborate design of advanced nanocarriers to benefit diverse loading requirements of size-varied therapy agents is of critical importance. Herein, we demonstrate a multifunctional drug carrier platform based on a hierarchical porous and -NH2-modified silica nanocarrier (FMSN) with a super high specific surface area and a large pore volume, which not only improves the loading capacity of both doxorubicin, a chemotherapeutic drug, and black phosphorus quantum dots (BPQDs), a kind of biocompatible photothermal agent, but also enhances the photothermal stability and biostability of the degradable BPQDs. The unique structure and surface design enable our multimodal platform with heat-stimulative, pH-responsive and sustained-release properties for chemo-photothermal synergistic cancer therapy. Both cytotoxicity experiments and in vivo study reveal that the combined therapy based on our multifunctional nanohybrids mediates the highest death rate of cancer cells compared to that of single chemotherapy or photothermal therapy. Our hierarchical mesoporous strategy provides an excellent drug delivery model for advanced chemo-photothermal synergistic targeted cancer therapy.

Stable lithium–sulfur batteries with high sulfur content fabricated by ultralight ochroma lagopus-derived carbon with dopamine shell as sulfur host

Breaking through low sulfur loading and shuttle effect are the key to achieve high performance lithium-sulfur battery. It is necessary to prepare an ultralight sulfur host with strong polysulfide adsorption/blocking ability. Herein, the polydopamine coated ochroma lagopus carbon (A-PDA@OLC) with super-high specific surface area is exploited as sulfur host for high-performance lithium-sulfur batteries. The cathode with 60.13 wt % sulfur content (2 mg cm−2 sulfur loading) delivered the higher initial capacity of 1294.27 mA h g−1 and excellent reversible capacity (959.13 mA h g−1 at 0.1C after 200 cycles). Moreover, when the sulfur content was increased to 82.30 wt% (4 mg cm−2 sulfur loading), the A-PDA@OLC@S cathode exhibits the higher reversible capacity of 1258 mA h g−1 at 0.1C and a prolonged cycle life (723 mA h g−1 after 250 cycles). The prepared PDA coated natural ultralight biochar are proven to be an effective strategy for the encapsulation and adsorption of lithium polysulfides(LiPSs), which demonstrates enhanced electrochemical performance for high-sulfur-loading Li–S batteries.

Effect of Microwave Sintering on Morphology and Structure of Porous Al2O3-SiO2 Ceramics

Mesoporous Al2O3-SiO2 ceramics were prepared by one-pot method. In this process, aluminum chloride hexahydrate (AlCl3·6H2O) and tetraethyl orthosilicate (TEOS) acted as the common precursors, and then the composite porous ceramics were obtained by vacuum freeze-drying (FD). Subsequently, the samples were sintered at 800°C, 1000°C and 1200°C by muffle furnace and microwave sintering device (MSD) respectively, and the crystalline transformation process has been characterized by X-ray powder diffraction (XRD). Furthermore, the properties of porous materials were characterized by Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the sintered samples still retain super high specific surface area (over 200m2/g), and microwave sintering can greatly reduce the crystallization temperature of porous alumina ceramics. This rapid sintering method also transforms porous ceramics from leaf-like structure to granular structure, and finally forms nanorod structure. The sintering mechanism was explained from the point of view of crystal growth law.

A template-free method for the synthesis of porous alumina with superhigh specific surface area and large pore volume

Abstract This work demonstrates a facile organic-free and template-free approach for synthesizing spindle-like alumina with large pore volume and high specific surface area via a gas-liquid interfacial method followed by calcination. The influences of different calcination temperatures on the porous alumina were systematically studied. The possible formation mechanism of the spindle-like structures was also investigated. The results exhibited that the as-obtained amorphous alumina calcined at 300 °C had superhigh surface areas (up to 853 m2/g). Furthermore, the adsorption performance of the as-prepared amorphous alumina with high surface area was also evaluated. This spindle-like amorphous alumina showed an excellent adsorption capacity (3284 mg/g) for the removal of Congo red from aqueous solution, which indicate this porous alumina may have great potential applications in adsorption and other related areas.

Polyvinylmethyldimethoxysilane reinforced methyltrimethoxysilane based silica aerogels for thermal insulation with super-high specific surface area

Abstract To overcome the interior brittleness of silica networks, polyvinylmethyldimethoxysilane reinforced methyltrimethoxysilane based silica aerogels (PRMSAs) were prepared via a facile strategy based on crosslinking polyvinylmethyldimethoxysilane with methyltrimethoxysilane in the sol-gel process and then drying in supercritical fluids. Benefiting from long-chain aliphatic hydrocarbons and abundant methyl groups, monolithic PRMSAs exhibit elastic recovery properties and super-high specific surface area, reaching up to 1479 ± 83 m2/g. As heat insulators, PRMSAs possess a low thermal conductivity of 0.029 W/(m·K) at ambient conditions. Our new method may greatly expand the usage of silica aerogels in thermal insulation applications.

N, O-enriched hierarchical porous graphite carbon flake for high performance supercapacitors

Super-high specific surface area (3319 m2 g−1) and N (3.64%), O (11.3%) containing hierarchical porous graphite carbon flake has been synthesized via simultaneous activation and graphitization of human harmful biomass-derived Firmiana simplex catkin. Due to the synergistic effects of KOH etching and carbide exfoliation, tube structure of C-700 can be effectively transformed the into flake structure of C-1-6. The C-1-6 based single electrode displays an excellent specific capacitance of 395 F g−1 at the current density of 0.5 A g−1 and superior rate capability with a high capacitance of 275 F g−1 at 50 A g−1. Furthermore, negligible 0.1% capacitance loss exists after 10,000 times of charging and discharge processes. Considerable energy densities of 11.52 Wh kg−1 and 55 Wh kg−1 can be obtained by solid-state and coin-type symmetric supercapacitors, respectively. This biomass-derived carbon can play a role in the field of carbon based supercapacitors.

Peony pollen derived nitrogen-doped activated carbon for supercapacitor application

Peony pollen is a cheap and readily available biomass material with a relatively high protein content. In this work, it was employed as an N-rich precursor to prepare the nitrogen-doped porous carbon for supercapacitor application. The porous carbon microspheres were prepared through a hydrothermal method and subsequent carbonization process. Notably, ammonium borofruoride and potassium hydroxide were employed respectively as an etchant and an activator to modify the porosity of the materials. The as prepared ANPPCs-700 has a super high BET specific surface area of 824.69 m2/g. The microstructure, chemical state and electrochemical properties of the product were investigated in detail. The prepared nitrogen-doped carbon microspheres exhibits excellent specific capacity of 209 F/g at a current density of 1A/g and remained 92.5% of the initial capacitance after 5000 deep cycles at 5A/g.

Review on Thermal Conductivity of the Graphene Reinforced Resin Matrix Composites

Graphene is a two-dimensional nanostructure filler with high thermal conductivity (5000 W/mK) and excellent mechanical properties, which has a very wide application prospect. Graphene is with super high specific surface area, which provides a greater contact area with polymer matrix. Then it is more easy to form the thermal conductive heat channels, which could improve the thermal conductivity of composite materials. The concentration, the ratio of geometrical diameters, the dispersion in the matrix and the interfacial bonding between graphene and the matrix materials will greatly affect the thermal conductivity of graphene reinforced composites. However, the graphene nanosheets can be easy to stack together and difficult to be dispersed into the solvent and polymer matrix. In order to improve the interfacial combination between graphene nanosheets and the matrix so as to reduce the interfacial thermal resistance of the composites, it is usually to modify the surface of graphene nanosheets, which mainly includes non-covalent modification and covalent modification. In this paper, researches on the thermal conductivity of graphene were reviewed, and the existing problems and the future research focus were also discussed.

Meso-/microporous carbon as an adsorbent for enhanced performance in solid-phase microextraction of chlorobenzenes

There is urgent demand for the design of advanced coating materials for solid-phase microextraction (SPME) for water quality monitoring and assessment because of the global occurrence of chlorobenzenes (CBs). In this study, we proposed a dual-order activation method in which potassium hydroxide is used to modify pre-activated calcium citrate to synthesize a highly developed meso-/microporous carbon (MMC). The as-obtained MMC presented well-developed porosity with a super-high specific surface area (2638.09 m2 g−1), abundant meso-/micropores (0.5–10 nm), high hydrophobicity, excellent thermal stability (>720 °C), and a partly graphitized structure. As a coating material for headspace-SPME, the MMC-coated fiber exhibited outstanding extraction capability for CBs (up to 48.5 times higher than that of commercial fibers), which may be attributed to multiple interactions between the MMC and the pollutants, including size selectivity, micropore filling, π-π stacking and hydrophobicity. Finally, a satisfactory method using an MMC-coated fiber coupled with gas chromatography and electron capture detection was developed with good linearity (1–1000 ng L−1, R2 > 0.9982), high enrichment efficiencies (enrichment factors, 861–7819), low limits of detection (0.003–0.072 ng L−1), excellent repeatability (0.7–5.3%) and reproducibility (1.7–5.1%), and outstanding recoveries (90.18–103.02%) when applied to determine trace CBs in real water samples. These results suggest that MMC is a promising coating material for the SPME of CBs.