Mesopore Ratio Research Articles

Synergistic sono-adsorption and adsorption-enhanced sonochemical degradation of dyes in water by additive manufactured PVDF-based materials

The present study proposes the first mechanistic model accounting for the most meaningful physico-chemical phenomena taking place in liquid phase adsorption processes under ultrasound. Initially, this study was aimed at developing an easy-to-make and easy-to-recover piezocatalyst for the degradation of RhB in water by combining the high piezocatalytical performance of BaTiO3 with a compatible piezoelectric support such as PVDF, manufactured by a customised additive manufacturing – direct ink writing system with in-situ poling. However, initial results showed that the resulting PVDF-BaTiO3 composite slabs performed worse than BaTiO3 piezocatalysts on their own, and that poling did not have any effect on their performance (82% RhB removal after 2 h when using either poled or unpoled PVDF-BaTiO3 composite slabs compared to 92% RhB removal after 2 h in presence of BaTiO3 piezocatalysts). Further investigation with pure PVDF materials demonstrated that, instead of piezocatalysis, synergistic ultrasound-assisted adsorption and sonochemical degradation were taking place, enabling the removal of >95% of the dye within 40 min of ultrasound treatment in the presence of 4 g L–1 of additive manufactured PVDF slabs. The results of this study and their evaluation with the mechanistic model proposed for liquid phase adsorption under ultrasound suggest that the adsorption of RhB on additive manufactured PVDF slabs was enhanced by the structure, higher specific surface ratio and higher volume of mesopores achieved through the 3D-printing process, as well as the minimisation of film resistance to mass transport due to ultrasound. Moreover, adsorption on additive manufactured PVDF enhanced the sonochemical degradation of the dye due to its high concentration in the adsorbed phase. This study demonstrates that adsorption processes, especially in the presence of PVDF materials, may be significantly more important in piezocatalysis than what has been reported to date, to the point that the synergistic combination of sono-adsorption and sonochemical degradation in presence of additive-manufactured PVDF slabs may be enough to achieve high removal rates of dyes in water.

Improving volumetric supercapacitors performance with additive-free solid cylinder design of O, Zn, and Cl multi-doped biomass-based carbon source

This study aimed to prepare a Peronema canescens leave-derived carbon-based material rich in O, Zn, and Cl (OZnC-x) multi-heteroatom sources using chemical impregnation and dual-gas pyrolysis. Porous carbon is subjected to integrated high-temperature pyrolysis of carbonization-physical activation in N2-CO2 atmospheres. The electrode material was uniquely designed to be solid cylinder additive-free with a high packing density. The optimized OZnC-850 exhibited multi-dopant O(5.79 %), Zn(13.24 %), Cl(1.27 %), a surface area of 145.721 m2 g−1, a well-matched mic(55.61 %)-mesoporous(44.39 %) ratio, and a high packing density of 1.25 g cm−3. At 1 Ag−1, OZnC-850 possessed a Cv of 288 F cm−3 with Cg of 231 F g−1 in aqueous electrolyte solution. The symmetric supercapacitors exhibited an energy output of 16.02 WhL−1 and 12.81 Whkg−1 at 494.89 W L−1 as well as 395.92 W kg−1. In conclusion, OZnC-x -based multi-dopant carbon-based, proved to be a promising candidate as an electrode material to enhance volumetric behavior of supercapacitors.

Activated carbon with high mesopore ratio derived from waste Zanthoxylum bungeanum branches by KNO3-assisted H3PO4 staged activation for toluene adsorption.

Waste Zanthoxylum bungeanum branches were used to prepare activated carbon adsorbents with high mesopore ratio by H3PO4 staged activation method with adding KNO3 additive. The prepared activated carbon adsorbents were characterized by SEM, BET, FT-IR, and XRD. The adsorption properties of the prepared activated carbon adsorbents were evaluated by the toluene adsorption/desorption in air. The quasi-first-order, quasi-second-order, and Bangham models were used to fit the obtained toluene adsorption results. The oxidative etching of KNO3 additive improved the pore-forming ability of the H3PO4 activator to enhance the activation pore-forming effects of the selected biomass raw material. The secondary pore-forming effects of K atoms promoted the effective expansion of the pore diameter in the activated carbon preparation process to prepare activated carbon adsorbents with high mesopore proportion. The specific surface area and mesopore proportion of the activated carbon adsorbents prepared by adding KNO3 additive exceeded 1100 m2/g and 71.00%, respectively, and the toluene adsorption capacity exceeded 370.00 mg/g. The rich mesopore structures can effectively reduce the toluene mass transfer resistance, which can promote the corresponding activated carbon adsorbent to be regenerated by low-temperature (40 °C) thermal desorption. The toluene adsorption on the prepared activated carbon adsorbents includes surface adsorption and diffusion in pore structures, and the toluene adsorption mechanism is more consistent with the Bangham kinetic model.

Controlled porous structures of soybean straw-based carbon via green liquefication and N/S in-situ doping facilitate supercapacitor performance at large current density

It is important to maintain supercapacitor performance at high current density by regulating the micropore/mesopore balance and surface functional groups of biomass carbons. Here, the biomass porous carbon was successfully prepared from agroforestry waste of soybean straw by green activation was introduced on the basis of in-situ doping. Effective liquefaction and doping environment for non-metal N/S doping was achieved via green liquefaction using polyethylene glycol 400 (PEG400). The micropore/mesopore ratio, hydrophilic properties, and active sites of the carbon materials were regulated and enhanced by combing N in-situ doping and green activation with potassium citrate. The obtained soybean straw-based carbon with N doping (SSL-N1) showed higher surface area (1698.9 m2 g−1) and mesopore ratio (78.15%). The mesopore/micropore ratio shortened the ion adsorption distance and increased the ion surface accessibility. The specific capacitance of materials could reach 276.8 F g−1 at a current density of 0.5 A g−1. As the current density expand by 20 times, the specific capacitance could be preserved at 216 F g−1, the capacity retention rate is 78.0%. Notably, the SSL-N1//SSL-N1 symmetrical supercapacitor could generated an energy density of 10.14 W h kg−1. The specific porous and surface structures of carbon composite materials could effectively alleviate the capacity attenuation in supercapacitors at high current density.

Effect of compression ratios on the sorption behaviors of bamboo fiber-based composites

The sorption behaviors of bamboo fiber-based composites (BFC) play a critical role on its applications due to its impact on the dimensional stability and biological durability of the material. The sorption behaviors of Neosinocalamus affinis BFC with compression ratios of 1.50, 1.83 and 2.17 were studied in this project, aiming to optimize the manufacturing process of BFC to reduce the sorption of final products. It was found that the hygroscopicity of BFC samples with all three compression ratios is much lower than that of raw bamboo at all the studied relative humidity (RH) levels. The BFC manufactured with 1.50 compression ratios showed the lowest equilibrium moisture content (EMC). The sorption ability of BFC showed some increase with increasing compression ratio especially when the relative humidity (RH) was above 60%. An evolution in moisture absorption model of BFC was proposed based on the changes in its wettability, pore structures, and chemical compositions. Both introduction of phenolic formaldehyde (PF) resin and material densification reduced the water transfer pathway such as bamboo cell lumens, pits, and gaps, as well as the water absorption space in cell wall. Meanwhile, the BFC with higher compression ratio had increased difficulty to absorb water. The increase in sorption ability of BFC with higher compression ratio at high RH environment is proved to be the consequence of the higher content of its mesopore ratio resulting in increased poly-layer water content. Therefore, the RH of application occasions is critical to determine the optical compression ratio of BFC combining with other performance requirements.

Tailored mesoporous structures of lignin-derived nano-carbons for multiple applications

This work uses a one-step KOH activation for lignin precursors to produce ultra-high mesoporous activated carbons (ACs) with an unprecedented combination of the surface area of 3207 m2 g−1 and mesopore ratio of 76%. The ACs are applied for supercapacitors (SCs) and methylene blue (MB) adsorption. The capacitance of the SCs in the three-electrode system reaches 812.3 F g−1 and demonstrates a remarkable maximum MB adsorption capacity of 1250 mg g−1. By modifying the process conditions, the mesopore ratio of ACs could be controlled from 10% to 80%. Compared with one-step activation, a two-step method produced microporous carbons with a lower surface area of 1227 m2 g−1 and a high micropore ratio of 73%. The capacitance of SCs with two-step ACs reached 228.1 F g−1 and the maximum adsorption capacity of 476.19 mg g−1 for MB adsorption. The two-step method limited the surface area but had a higher oxygen surface functionality, benefiting its electrochemical performance. A techno-economic analysis reveals that the one-step KOH activation-based process develops ACs with a minimum selling price of $7648/ton. This work demonstrates tuning the processing-structure-property-performance relationship of lignin-based ACs to make an economically viable domestic carbon source.

Defective Carbon Derived Using a Dissolution-Recrystallization Strategy for Oxygen Reduction Electrocatalysis.

Dopant-free defective carbon electrocatalysts have been considered as promising alternatives to traditional precious metal electrocatalysts recently. Compared with precious metal catalysts and transition-metal catalysts, since there are no metals doped, electrochemical devices assembled with dopant-free defective carbons are free from environmental pollution and subsequent recovery problems. In order to obtain abundant carbon defects with high-intrinsic catalytic activity, the synthesis of dopant-free defective carbons requires complex and harsh preparation conditions. Therefore, the construction of active defects with efficient utilization, especially through a simple process, is still a great challenge for the development of dopant-free defective carbon electrocatalysts. Herein, dissolution-recrystallization strategy was employed to design Zn-MOF-74 precursors for the synthesis of dopant-free defective carbons, realizing the synchronous manipulation of high ratio of carbon defects and highly exposed mass transfer channels. One-dimensional porous defective carbon nanorods (d-CNRs), which exhibited excellent oxygen reduction reaction (ORR), electrocatalytic activity, and molecular selectivity, were synthesized by directly carbonizing rodlike Zn-MOF-74 precursors. Attributed to the dissolution-recrystallization strategy, with the activation of in situ-formed ZnO, the synthesized d-CNRs exhibited unique pore-crack nested porous structures, which carried abundant defects as activity sites for ORR and showed a surprisingly high specific surface area of 2459 m2/g with a high ratio of mesopores. d-CNRs also showed promising applications in Zn-air batteries with a stable long-term discharge of no obvious voltage drop after 60 h. The dissolution-recrystallization strategy provided a simple controllable pathway for the efficient construction of dopant-free defective carbon electrocatalysts.

Self-assembled nano Co-Ni pompon structured hierarchical porous carbon and the excellent electrochemical capacity

Supercapacitor is an energy storage device with excellent performance which has been studied in recent years. Biomass-based porous carbon materials are widely used as electrode materials for supercapacitors because of their good pore structure and electrical conductivity. A unique nanoscale pompon with structured porous carbon as core was synthesized by a two-stage activation of H3PO4-K2C2O4 combined with hydrothermal self-assembly in this research. Results showed that the specific surface area of the hierarchical porous carbon sample was up to 1608.1 m2/g with the mesoporous ratio of 54.26%. The self-doped Co-Ni elements were successfully entered into the channel of carbon core and then the self-assembled nano pompon epidermis was formed. Interleaving nanorods with unique characteristics as dispersion at the bottom and aggregation at the top were evenly grown on the surface of the pompon, forming a 3D network structure with a mass of cavities, which brought with excellent faradaic pseudocapacitance of electrode materials. The energy density and power density of the asymmetric supercapacitor assembled by nano pompom and porous carbon reach 30.4 Wh/kg and 1367.1 W/kg respectively.

A plasma-assisted approach to enhance density of accessible FeN4 sites for proton exchange membrane fuel cells

Enhancing the density and utilization of FeN4 sites can serve as a viable approach to enhance the catalytic efficacy of iron nitrogen carbon (FeNC) catalysts for oxygen reduction reaction (ORR). Herein, we present a plasma-assisted method for enhancing the porosity of nitrogen-doped carbon. Our findings indicate that the ideal ratio of mesopore to micropore area is 0.463. This ratio not only promotes the diffusion of Fe3+ but also creates additional active sites for Fe3+ loading, leading to an increase in the number of available FeN4 sites in FeNC electrocatalysts during pyrolysis. The density (76.5 μmol g−1) and utilization (21.08 %) of d-FeNC-30 are significantly higher than those of FeNC without plasma treatment, with a 2.8-fold and 2-fold increase, respectively. Remarkably, it displays outstanding performance, evidenced by a half-wave potential of 0.835 V (vs. RHE) in a 0.1 M HClO4 solution and a power density of 0.860 W cm−2 in proton exchange membrane fuel cells (PEMFCs). The developed plasma-assisted approach for improving the site density (SD) and utilization of FeN4 provides a new perspective for high-performance ORR FeNC catalysts.

Efficient removal of methylene blue via two-step modification hazelnut shell biochar: Process intensification, kinetics and thermodynamics

Porous carbon materials with ultra-high specific surface area and adjustable pore structure characteristics were prepared from food industry waste hazelnut shells for the adsorption of methylene blue (MB) wastewater by two-step activation by impregnation with ZnCl2 followed by chemical activation with KOH. The Fusso effect, which can reduce the size of MB molecules, was further used to enhance the adsorption of MB on porous carbon. The results show that both HSBC-a and HSBC-a-b have ultra-high specific surface area (2979.59 m2/g for HSBC-a, 2882.73 m2/g for HSBC-a-b). The mesopore ratio of HSBC-a-b (Vmeso/Vtotal % = 14.05%) was doubled compared to HSBC-a. It showed an excellent adsorption performance of 694.03 mg/g for MB. It showed a fast adsorption kinetics and the adsorbed amount increased to 882.46 mg/g at 0.1 M NaCl solution. In addition, adsorption processes were studied using adsorption kinetics and adsorption isotherm model fitting. The results of this research confirm that hazelnut shell is a kind of promising and sustainable porous carbon raw material, and its ultra-high specific surface area and adjustable pore structure characteristics are favorable for the efficient treatment of MB from dyeing wastewater. This work could provide potential guidance for the high-value utilization of waste hazelnut shell biochar.

Fine-tuning mesoporous silica properties by a dual-template ratio as TiO2 support for dye photodegradation booster

Titanium dioxide (TiO2) has been integrated into the surface of mesoporous silica (SMG) synthesized via the hydrothermal approach and a dual template CTAB-Gelatin. XRD, nitrogen adsorption, FTIR, SEM-EDX, and UV–Vis DR spectroscopy were performed to evaluate a 1 wt% TiO2/SMG material. After titania incorporation, the addition of gelatin during the synthesis of SMG increases the pore volume to 0.76 cc/g. The expansion of the silica pores is caused by the development of TiO2 crystal grains on the mesoporous silica-gelatin. An increase in the gelatin-CTAB to mesoporous silica weight ratio modifies the surface area, pore size, and particle size without compromising the meso-structure. In this research, the TiO2/SMG composite demonstrated much greater photodegradability for methylene blue (MB) than the TiO2/mesoporous silica sample without gelatin. The experimental results indicate that the photocatalytic activity of methylene blue from SMG titania/silica samples is reliant on the adsorption ability of the composite and the photocatalytic activity of titania, with optimal activity from samples with the highest surface area and pore volume, which directly increase the Ti: Si ratio and decrease the photodegradability of the composite when the ratio is too high or too low.

New Porous Carbon Material Derived from Carbon Microspheres Assembled in Hollow Carbon Spheres and Its Application to Toluene Adsorption.

In this paper, a new porous carbon material adsorbent was prepared using carbon microspheres assembled in hollow carbon spheres (HCS) with a hydrothermal method. Transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and Raman spectroscopy were used to characterize the adsorbents. It was found that the diameter of carbon microspheres derived from 0.1 mol/L glucose was about 130 nm, which could be inserted inside HCS (pore size was 370-450 nm). The increase in glucose concentration would promote the diameter of carbon microspheres (CSs), and coarse CSs could not be loaded in the mesopores or macropores of HCS. Thus, the C0.1@HCS adsorbent had the highest Brunauer-Emmett-Teller surface area (1945 m2/g) and total pore volume (1.627 cm3/g). At the same time, C0.1@HCS posed a suitable ratio of micropores and mesopores, which could provide adsorption sites and volatile organic compound diffusion channels. Moreover, oxygen-containing functional groups -OH and C═O in CSs were also introduced into HCS, and the adsorption capacity and regenerability performance of the adsorbents were improved. The dynamic adsorption capacity of C0.1@HCS for toluene reached 813 mg/g, and the Bangham model was more suitable for describing the toluene adsorption process. The adsorption capacity was stably kept above 770 mg/g after eight adsorption-desorption cycles.

Structural changes and electrochemical properties of mesoporous activated carbon derived from Eucommia ulmoides wood tar by KOH activation for supercapacitor applications

In this study, mesoporous activated carbon (AC) was synthesized by thermochemical activation of Eucommia ulmoides Oliver (EUO) wood tar by using KOH as the activator. The pore structure, surface characteristics, graphitization degree and electrochemical properties of ACs synthesized by one-step and two-step activation were systematically investigated. The results showed that the two-step activation could effectively improve the relevant properties of AC as compared to those from the one-step activation. The maximum specific surface area (SSA) and pore volume of AR3–1 (1:3 mass ratio of EUO wood tar to activator at one-step activation process) could be increased than AR3–2 (1:3 mass ratio of carbonized product to activator at two-step activation process) by 26.08% and 20.27%, respectively. Additionally, the mesoporous ratio of AR3–2 can reach 71%, indicating a well-developed mesoporous structure. Meanwhile, the highest SSA of AR5–2 (1:5 mass ratio of carbonized product to activator at two-step activation process) synthesized by two-step activation can rise to 3354.8 m2/g, and the pore volume can reach 1.78 m3/g. Besides, the specific capacitance of AR3–2 reached 510.54 F/g at a current density of 0.2 A/g in 1 M KOH aqueous electrolyte in the three-electrode system, possessing better electrochemical stability. Overall, as a precursor of mesoporous activated carbon, the AC synthesized from EUO wood tar exhibits excellent structural and electrochemical performance. This study has a guiding significance for the synthesis of high-performance mesoporous carbon from biomass tar.

Nanoarchitectonics of fulvic acid based oxygen-rich hierarchical porous carbon with high specific surface area as supercapacitor electrodes

The pore structure of carbon materials strongly influences the electrochemical performance of carbon electrodes. Thus, carbon material pore structure modification methods need to be further explored to improve carbon electrode performance. In this work, fulvic acid is used as a carbon precursor to prepare oxygen-rich hierarchical porous carbon (OAHPC) by H2O2 oxidation followed by synergistic activation with KOH. H2O2 oxidation significantly increases the oxygen functional groups on the surface of the fulvic acid, which helps coordinate the KOH activation process. The prepared OAHPC has a mesopore ratio of 67.77%, a specific surface area (SSA) of 3362 m2·g−1, a total pore volume of 2.23 cm3·g−1, and an oxygen content of 34.01 wt%. The OAHPC is used as a supercapacitor electrode material in a three-electrode system. This OAHPC electrode displays a high specific capacitance of 453 F·g−1 at 0.2 A·g−1 in 6 M KOH as well as outstanding cyclic stability (86.8% capacitance retention after 5000 cycles). This method provides a new strategy for adjusting the pore structure of porous carbon materials.

Adsorption of antibiotics from wastewater by cabbage-based N, P co-doped mesoporous carbon materials

Research on low-polluting, economical, and reliable antibiotic adsorption materials is of great significance for reducing pollution in the pharmaceutical and aquaculture industries. Herein, N, P co-doped carbon material (PCC500) with a high specific surface area of 1400 m2/g and a high mesoporous ratio of 89.9% were prepared from cabbage waste by H3PO4 hydrothermal combined with activation. PCC500 showed good adsorption performance for various antibiotics, including chloramphenicol (CHL), tetracycline (TC), ofloxacin (OFX) and erythromycin (ERY). 99% removal efficiency and 247 mg/g adsorption capacity of TC on PCC500 were obtained at 298 K (C0 = 50 mg/L), and 471 mg/g of the maximum adsorption capacity of was achieved at 318 K. The adsorption kinetics and thermodynamic analysis indicated that there was chemisorption during the adsorption process. A series of characterizations including SEM, EDS, N2 adsorption and desorption, FTIR, XPS showed that the abundant pore structure and P, N functional groups are important factors affecting the adsorption performance, and the graphite-N and C3-PO structures in PCC500 could be the important active sites responsible for antibiotic chemisorption. Moreover, PCC500 exhibits good resistance to impurity ions and cyclic stability.

Nitrogen-Doped Porous Carbon-Supported PtCo Nanoparticle Electrocatalyst for Oxygen Reduction Reaction Prepared by a Dual-Template Method

A strategy for preparing nitrogen-doped porous carbon (NPC-Co) using a dual-template method is reported in this study. The catalyst (PtCo/NPC-Co) with high catalytic performance for the oxygen reduction reaction (ORR) was developed after adding PtCo metal nanoparticles (NPs). Polydopamine can complex metals, encapsulate templates, and reduce metals. Therefore, polydopamine was selected as the carbon and nitrogen source. Then, ZnO and Co NPs were used as a double template to obtain a carrier (NPC-Co) with a high mesoporous ratio and high N content. The PtCo alloy NPs are homogeneously anchored on the support by highly dispersed N atoms originating from NPC-Co. PtCo/NPC-Co exhibited excellent catalytic performance and durability for oxygen reduction. The mass activity of PtCo/NPC-Co is 4.8 times that of commercial Pt/C catalysts. Furthermore, PtCo/NPC-Co showed excellent durability. The mass activity of PtCo/NPC-Co decreased by only 23% compared with that of Pt/C (49%) after 20,000 cycles. The interaction effect between NPC-Co and PtCo NPs enhanced the overall electrocatalytic performance. Additionally, the ORR mechanism is discussed in this study to advance our understanding of the electrocatalytic structure–activity relationship.

MnO2 nanospheres integrated into hierarchical porous carbon as electrode for high performance asymmetrical supercapacitors

Hierarchical porous carbon (HPC) is considered as an ideal electrode material for supercapacitors on account of its high stability and developed pore structure. MnO2, possessing ultrahigh theoretical capacitance, can provides pseudocapacitance to facilitate electrochemical performances. Herein, HPC with large specific surface area (1153 m2 g−1) and abundant mesopores (95.76 % mesopore ratio) is prepared via ZnCl2 activation, which can act as the support and substrate for MnO2. Subsequently, in-situ synthesis of MnO2 nanospheres and preparation of MnO2/HPC composites (MnO2@HPCs) are realized simultaneously by a simple redox reaction. Benefiting from high conductivity of HPC (4.07 S m−1) and moderate size of MnO2 nanospheres (∼40–50 nm), MnO2@HPCs exhibit an excellent specific capacitance (521 F g−1 at 0.5 A g−1 and 468 F g−1 at 1 mV s−1) and pseudocapacitance effect in three-electrode system. Further, the asymmetric supercapacitor adopting MnO2@HPC160 and HPC as the cathode and anode delivers a superior capacitance value (74 F g−1 at 0.5 A g−1), outstanding rate performance (79.7 % at 10 A g−1) and remarkable energy density of 32.93 Wh kg−1 in 1 M Li2SO4 electrolyte. These results demonstrate that the MnO2/hierarchical porous carbon composite is a promising candidate as electrode material for high-performance supercapacitors.

Controllable synthesis of zeolitic imidazolate frameworks and the peanut shell carbon composite for sensitive and selective detection of Pb2+ and Cd2+ ions

Zeolitic imidazolate frameworks (ZIF) and the peanut shell carbon (PSC) composite (ZIF-8 @PSC) nanocomposite is successfully fabricated and exhibits superior current response for simultaneously detecting Pb2+ and Cd2+. The obtained composite has been characterized via SEM, TEM, XRD, FTIR, N2 adsorption-desorption methods. The suitable pore structure of ZIF-8 @PSC with the highest mesoporous ratio (ca. 11%) is conducive to mass transportation and charge transfer. The available specific surface area (236.6 m2 g−1), the lowest internal resistance (81.8 Ohm) as well as the synergistic effect between ZIF and PSC in ZIF-8 @PSC(4−1) electrode contribute to the enhanced current signals for the detection of Pb2+ and Cd2+ in aqueous solution. Additionally, the cyclic voltammetry investigation reveals that the kinetic process of the target heavy metal ions on the surface of the ZIF-8 @PSC(4−1) electrode is controlled by diffusion, which is verified by the Warburg impedance in low frequency region. Under the optimum conditions, the peak currents are linearly related with the concentration of Pb2+ and Cd2+ in the range of 0.1–8 µM (Pb2+) and 0.06–9 µM (Cd2+), and the corresponding limit of detection is 8.25 nM (S/N = 3) and 16 nM (S/N = 3), respectively, which are superior to other reported results. Based on the outstanding selectivity, stability, repeatability, and reproducibility, the analytical performance for the detection of the metal ions is assessed individually and simultaneously. It is found that the obtained method exhibits simultaneous sensing ability toward Cd(II) and Pb(II). During the multi-component sample, the detection and quantification of Pb(II) is more sensitive. Finally, the proposed method is applied to detect Pb2+ and Cd2+ in domestic sewage and satisfactory results have been achieved.

Organic salt-derived phosphorus-doped mesoporous carbon for high performance supercapacitors

Phosphorus-doped mesoporous carbons (PMCs) were prepared using a self-doping and self-templating approach via direct pyrolysis of sodium phytate (C6H17NaO24P6). The one-pot method allows simultaneous carbonization and P doping, eliminating the need for pre-synthesis or post-activation treatment. The C6H17NaO24P6 is the source of both carbon and phosphorus, and the nano-Na4P2O7 particles produced during pyrolysis act as hard templates for the honeycomb mesoporous structure with high specific surface area (884–827 m2/g), large mesopore volume ratio (67%–75%) and rich phosphorus content (0.53–2.34 at%). As electrodes of supercapacitors in 6 mol/L KOH, the PMCs showed outstanding performance with a high capacitance of 202 F/g and excellent rate performance of 148 F/g at 30 A/g. In addition, the PMCs-based symmetrical supercapacitors can operate in an expanded working voltage of 0–1.6 V in 3 mol/L H2SO4 aqueous electrolytes with high-density energy of 11.8 Wh/kg.

“Mortar-and-cobblestone” type carbon pellets with interlinked C3H6-philic domains and mesoporous transport channels for propylene/propane separation

Adsorptive separation of propylene/propane is an energy efficient way to produce high purity propylene, which is an essential chemical for the production of a variety of important monomers/polymers. The central task is to devise porous materials that can recognize the subtle difference between propylene/propane. The understanding of the selective adsorption and dynamic diffusion behaviors in nanopores at different length scales is key for efficient separation, however, remains elusive. Here we target at this issue by devising “mortar-and-cobblestone” type carbon pellets (MCCs) as model adsorbents, which showed tunable combinations between micropores and mesopores. As the volume ratio of mesopore to micropore increases from 0.37 to 1.33, the adsorption capacity of propylene increases from 2.4 to 2.9 mmol g−1 at 100 kPa and 298 K, and its diffusion rate is 3.28 times increased. In particular, the adsorption of propane displays a unique two-step diffusion behavior in the MCCs, which quantifies the contribution of the mass transport mesopores and gas sieving micropores to their adsorptive separation. In addition, the MCCs are in pellet form and mechanically strong with a compressive strength of 17.4 MPa, which further ensures their potential in molecular separation practice.