Journal of Porous Materials最新文献

A simple suspension polymerization coupling with oxidative stabilization, carbonization, and H₂O steam activation are applied to synthesize a series of hierarchical porous millimeter-sized pitch-based spherical activated carbons (PSAC). The as-obtained PSAC possess a tunable specific surface area from 975 m² g^− 1 to 1761 m² g^− 1, a pore volume of 0.44 ~ 0.82 cm³ g^− 1, and spherical morphology via regulation of H₂O activation time. The CO₂ adsorption capacity is closely related to the ultramicroporous volumes below 0.2 bar. The introduction of rich micropores has a positively influence on CO₂ adsorption capacity that can reach 2.59 mmol g^− 1 at 1.0 bar. When the pressure increasing to 5.0 bar, the micro-mesoporous PSAC shows higher CO₂ adsorption capacity of 7.23 mmol g^− 1 at 5 bar than microporous PSAC, indicating that the introduction of moderate mesopores can accelerate CO₂ diffusion rate and improve the utilization of micropores active adsorption sites. Based on the ideal adsorption solution theory (IAST), the CO₂/N₂ and CO₂/H₂O adsorption selection factors S_ads of PSAC are as high as 49.9 and 8.29, respectively. Therefore, PSAC with high adsorption/desorption rate, good selectivity for CO₂/N₂ and CO₂/H₂O, excellent renewability, and easy mass production provide potential options for industrial application of CO₂ capture.

In this study, a high-performance microporous carbon adsorbent for carbon dioxide adsorption was prepared from thorny pear residue, with KOH as the pore-forming agent and urea for modification to enrich nitrogen in the microporous carbon. The effects of activation temperature and urea addition on the pore structure and carbon dioxide adsorption capacity of the microporous carbon were studied. The microporous carbon was characterized using N₂ adsorption/desorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR). The results showed that the optimum preparation conditions for the microporous carbon were an activation temperature of 700 °C and urea addition of 15wt%; the specific surface area of CAC-15-1.5-700 microporous carbon was 1386m²g^− 1, the micropore volume was 0.584cm³g^− 1, and the maximum carbon dioxide adsorption capacity was 3.80mmolg^− 1, indicating excellent CO₂ adsorption ability. The nitrogen elements on the microporous carbon existed mainly in the form of pyridine N (N-6), pyrrole N (N-5), and quaternary N (N-Q) functional groups, and the high N-5 content was an important factor for carbon dioxide adsorption.

Development of recycling pathways to produce sustainable and high-surface area carbon materials using crop-waste biomass is highly desirable for the design of cost-effective energy storage devices. In this study, three different activated carbon-based materials for supercapacitor application were prepared via simple metal halide activation on crop- waste biomass, specifically from the banana plant derivatives. The prepared samples with the single step activation show exceptional high surface area and large porosity, which are essential for elevating the energy storage performance. Among the different samples developed, stalk-derived activated carbon shows the highest surface area of 1311 m²/g and the average pore diameter of 1.77 nm. Nevertheless, all the samples constitute of three different porosities including micro-, meso-, and macro-pores responsible for the energy storage application. When tested for flexible electrode using porous carbon coated hydrophilic carbon cloth in symmetric supercapacitor, the device exhibits high specific/areal capacitance of 166.3 F/g/415.7 mF/cm² at a current density of 3 mA/cm² with exceptional cycling stability of 94% retention after 10,000 cycles. Moreover, the symmetric supercapacitor device enables the maximum energy and power densities of 17.2 Wh/kg and 2214 W/kg, respectively. This simple approach illustrates the utilization of biomass waste as an inexpensive resource for the development of energy storage devices with high energy density and power densities.

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The effect of treating SBA-15 with a piranha solution at room temperature was studied for purposes of stabilizing a WO₃ film deposited by Atomic Layer Deposition (ALD). For unmodified SBA-15, the film was found to migrate out of the SBA-15 pore structure between 573 and 773 K; however, WO₃ remained within the pores in piranha-treated samples at 773 K, as demonstrated by X-Ray Diffraction and Transmission Electron Microscopy. Although N₂ adsorption isotherms showed that the pore structure of SBA-15 was unaffected by the piranha treatment, the silanol content increased, as shown by water adsorption isotherms and Diffuse Reflectance Infrared Spectra of the silanol region. Temperature-programmed desorption results for 2-propanol also suggested that the silanols were more reactive in the piranha-treated samples. The results demonstrate the importance of surface modification of SBA-15 for the preparation of supported-oxide catalysts.

High-performance carbon-based cathode materials were prepared by means of a facile eco-friendly and cost-effective molten salt carbonization of lotus leaves in eutectic (Na/K)₂CO₃ melt at 850 °C for aqueous zinc-ion hybrid supercapacitors (ZHSCs). Coin-type ZHSCs assembled as Carbon//Zn@Zn₃(PO₄)₂ delivered 164.3 F g^− 1 at 0.2 A g^− 1 and 95.2 F g^− 1 at 20 A g^− 1 with capacitance retention of 57.9% using 2 M ZnSO₄ solution as electrolyte. Meanwhile, it delivered the maximum energy density of 65.2 Wh kg^− 1 at 169.0 W kg^− 1 and the maximum power density of 13.3 kW kg^− 1 at 23.3 Wh kg^− 1. Benefitting from the multifunctionally interface-modified Zn₃(PO₄)₂ layer acting as physical barrier and Zn²⁺-transfer ionic conductor, it revealed outstanding recyclability with capacitance retention of 96.6% and coulombic efficiency of 99.6% after 10,000 charge-discharge cycles at 1 A g^-1. The synergistic effect on energy storage performance was discussed between porous structure, specific surface area, heteroatom doping and electrical conductivity.

ZSM-5 is widely used in the field of catalysis due to its stability and tunability. Its acidity can be adjusted not only by varying the initial gel composition, but also by incorporating different types of template to enhance its performance. Both [Ga]-MFI and [Ga, Al]-MFI have demonstrated promising performance in the catalytic trioxane of formaldehyde synthesis. However, there is currently a paucity of research examining the influence of different templates on the catalytic performance of [Ga]-MFI and [Ga, Al]-MFI. The influence of different templates on the structure, morphology, and pore structure of the zeolite has been revealed through the application of characterisation techniques, including XRD, MAS NMR spectroscopy, ICP-OES, BET, and SEM. The impact of different templates on the acid properties of [Ga]-MFI and [Ga, Al]-MFI was assessed using NH₃-TPD and Py-IR. The results of the experimental investigation into the catalytic performance of zeolites synthesised with larger molecular-structured templates indicate that these zeolites exhibit superior catalytic performance. Furthermore, the introduction of Na + ions has been observed to reduce the space-time yield of the products.

High energy storage density, affordability, and environmental friendliness are the key requirements for materials used in thermal energy storage systems. A new composite thermal energy storage material (TESM) with all these requirements was fabricated by utilizing a biochar matrix. Biochar was derived from the slow pyrolysis of forestry residues, an abundant source of underutilized biomass in Canada. The results of this experimental study indicate that the carbonization conditions of the biomass affect the structure and surface morphology of the biochar and consequently its thermal properties. Amongst the carbonization conditions that were investigated in this study, a peak temperature of 800 °C with a heating rate of 2.5 °C/min yielded a biochar with an energy storage capacity of 508 J/g. This biochar was then used as a matrix for fabricating the composite TESM with salt hydrate. The composite showed high thermal stability after ten hydration/dehydration cycles with an average thermal energy storage capacity of 3795 J/g. The cost of thermal energy storage in this composite was found to be $0.50 CAD /kWh_th.

Herein, copper sulfide loaded mesoporous organosilica nanospheres with a triple-shelled hollow structure (CuS/tHMONs) are successfully synthesized. The resulting CuS/tHMONs nanospheres exhibit a uniform diameter of 340 nm, mesoporous channels with a diameter of 3.8 nm, large pore volume, and triply separated cavities. High-angle annular dark-field scanning electron microscopy (HAADF-STEM) images confirm the presence of a high content of CuS nanoparticles within the CuS/tHMONs composite nanospheres. Moreover, the CuS/tHMONs nanospheres demonstrate high photothermal conversion efficiency and excellent photothermal stability. In vitro experiments reveal excellent biocompatibility of the CuS/tHMON nanospheres, and cytotoxic assays demonstrate their effectiveness in killing cancer cells through photothermal therapy.

Graphene aerogel (GA) is a promising material for thermal management applications across many fields due to its lightweight and thermally insulative properties. However, standard values for important thermal properties, such as thermal conductivity, remain elusive due to the lack of reliable characterization techniques for highly porous materials. Comparative infrared thermal microscopy (CITM) is an attractive technique to obtain thermal conductance values of porous materials like GA, due to its non-invasive character, which requires no probing of, or contact with, the often delicate structures and frameworks. In this study, we improve upon CITM by utilizing a higher resolution imaging setup and reducing the need for pore-filling coating of the sample (previously used to adjust for emissivity). This upgraded setup, verified by characterizing porous silica aerogel, allows for a more accurate confirmation of the fundamental thermal conductivity value of GA while still accounting for the thermal resistance at material boundaries. Using this improved method, we measure a thermal conductivity below 0.036 W/m⋅K for commercial GA using multiple reference materials. These measurements demonstrate the impact of higher resolution thermal imaging to improve accuracy in low density, highly porous materials characterization. This study also reports thermal conductivity for much lower density (less than 15 mg/cm³) GA than previously published studies while maintaining the robustness of the CITM technique.