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This paper investigates the particle breakage mechanism of construction waste recycled aggregates [including recycled concrete (RC) as the strong component, recycled brick (RB) as the weak component, and natural gravel (NG) as the control strong component] under different load conditions. Through compression tests and mathematical model analysis based on the Weibull distribution, the study examines the changes in relative breakage rate (BE) and void fraction (Vc) of multicomponent recycled aggregates. The results reveal that under load, particle breakage occurs universally in recycled aggregates, especially in samples with higher RC content, which show a higher survival rate for larger particles and a reduction in smaller particle content. Additionally, the "survival of the fittest" effect, driven by differences in particle strength, becomes more pronounced as the strength difference increases. Incorporating NG into recycled aggregates can slow down the reduction in void fraction caused by particle breakage. Through the relationship model between load levels and brick-concrete ratios, the evolution of BE and Vc of recycled aggregates can be predicted, providing theoretical support for the design and application of permeable concrete. [ABSTRACT FROM AUTHOR]

The permeability performance made of recycled aggregate pervious concrete with macropores (M-RAPC) relates greatly to the macropore structure and seepage behaviors. However, the mechanism of the influence of pore structure on the permeability of M-RAPC is still unclear. Based on the high-resolution X-ray computer tomography (CT) and image processing technology, a three-dimensional (3D) pore structure model with macropore (>0.15 mm) was constructed, and the dimension of the representative elementary volume (REV) was determined to be 450×450×450 voxel3. Then, the quantitative characterization of the topological structure of macropore space and the simulation of pore flow were conducted. Finally, the relationship between macropore structure parameters and seepage behavior was discussed. The results showed that about 80% of macropores are in the range of 0.15–1 mm, and the pore coordination number is mostly concentrated within 20. The macropore distribution shows a great spatial heterogeneity, showing that the permeability anisotropy index is mainly larger than 1, and even up to 8. Besides, the permeability performance of M-RAPC is significantly correlated with macropore parameters (effective porosity, tortuosity, and fractal dimension). In summary, this study can better reveal the relationship between pore structure and seepage behaviors in M-RAPC and provide a reference for the skeleton structure and permeability performance optimization design of M-RAPC. [ABSTRACT FROM AUTHOR]

In this report, multiple-shell hollow silver and hematite composite microsphere has been prepared by using carbonaceous saccharide microsphere as template. The products were characterized by X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). The core size and shell thickness of hollow spheres obtained can be manipulated by changing the concentration of metal salt. The unique multiple-shell hollow silver and hematite composite microspheres may be potentially used as gas-sensor materials for detecting various toxic gases.DOI: http://dx.doi.org/10.5564/mjc.v12i0.163 Mongolian Journal of Chemistry Vol.12 2011: 7-15

Anode materials have limited the development of sodium-ion batteries (SIBs). In this paper, the novel pomegranate-like mesoporous double carbon-coated Fe2P nanoparticles (Fe2P@C@NC), in which Fe2P is confined in the thin carbon shell derived from phytic acid and then wholly embedded into N-doped carbon network, can be applied as anode materials for SIBs. The elaborated structure presents several prominent merits, such as large specific surface area, pore-volume, excellent electronic conductivity network, and buffering volume expansion. All of these endow the structural integrity of Fe2P@C@NC material with excellent performance during charge–discharge cycles and guarantee speedy electrode reaction kinetics. As SIBs anode, Fe2P@C@NC material delivers an excellent reversible specific capacity of 408 mAh g−1 with almost no decay after the 100th cycles. And it also features excellent rate capability and splendid durability (attenuation rate of 0.05% per cycle with 1000th cycles) at high current density. These results confirm that the unique self-confined growth strategy has a great practical value in synthesizing advanced materials for next-generation energy storage systems. [ABSTRACT FROM AUTHOR]

Improving the electron–hole separation efficiency and accelerating the reaction kinetics of semiconductors are effective methods for improving the photoelectric catalytic activity of TiO2. In this study, sulfur-doped TiO2 (S–TiO2) nanorod arrays grown on a fluorine-doped SnO2 transparent conductive glass were successfully prepared using a microwave-assisted method for the photoelectrochemical (PEC) biosensing of glucose. The charge separation efficiency on S–TiO2 was evaluated by subjecting the prepared material to X-ray photoelectron spectroscopy, PEC measurements, and theoretical calculations based on density functional theory. The results clearly showed that the sulfur impurity state could not only reduce the bandgap but also serve as "stairs" to facilitate the electron transfer. Sulfur atoms that were successfully doped into TiO2 significantly promote the separation of the photogenerated carriers and improve the photocatalytic activity of the photoelectrode. Consequently, excellent glucose-detection sensitivities of 54 and 19 μA mM−1 cm−2 were achieved for fragments with sizes of 0.1–1.5 and 2–12 mM, respectively. [ABSTRACT FROM AUTHOR]

Uniform-size In2O3 hollow spheres were synthesized using carbon microspheres as sacrificial template and In(NO3)3 as the indium resource. The effects of different solvents on the structure and morphology of as-prepared samples were discussed, and it was found that the shell thickness of In2O3 hollow microspheres could be controlled by changing solvents. The formation mechanism of the In2O3 hollow microspheres was also investigated. The gas-sensing results indicated that all of the as-prepared samples showed high gas-sensing response and excellent selectivity to formaldehyde and In2O3 hollow microspheres had an advantage over the bulk In2O3. Notably, In2O3 hollow microspheres with the shell thickness of 20 nm were fabricated by methanol solution and showed a higher response value of 41 toward 100 ppm HCHO than those of InO hollow microspheres obtained by using other solvents. InO hollow microspheres had good selectivity, high response and fast response-recovery, which made this product a promising gas-sensing material for detecting formaldehyde. [ABSTRACT FROM AUTHOR]

Highlights: [•] Mesoporous TiO2 hierarchical tubular superstructure (MTNHTS) has been successfully synthesized. [•] The structure is 1–2μm in diameter and 6–10μm in length, which consists of mesoporous nanosheets. [•] The growth mechanism of such a unique structure has been discussed. [•] The photocatalytic activity and lithium ion batteries performance are investigated. [•] MTNHTS manifest enhanced performances of photocatalysis and Li-ion batteries superior to P25. [ABSTRACT FROM AUTHOR]

The energy and environmental crises have forced us to search for a new green energy source and develop energy storage and environmental restoration technologies. Fabrication of carbon functional materials derived from coal has attracted increasing attention in the energy storage and gas adsorption fields. In this study, an N, O-co-doped porous carbon/carbon nanotube composite was prepared by functionalizing coal-based porous carbon with carbon nanotubes (CNTs) and ionic liquid via annealing. The resulting material not only inherited the morphology of CNTs and porous carbon, but also developed a three dimensional (3D) hierarchical porous structure with numerous heteroatom groups. The N, O co-doped porous carbon/CNT composite (N, O-PC-CNTs) showed a surface area of 2164 m 2 g -1 , and a high level of N/O dopants (8.0 and 3.0 at%, respectively). Benefiting from such merits, N, O-PC-CNTs exhibited a rather high specific capacitance of 287 F g -1 at a current density of 0.2 A g -1 and a high rate capability (70% and 64% capacitance retention at 10 and 50 A g -1 , respectively) in a three electrode system. Furthermore, an N, O-PC-CNT symmetrical supercapacitor showed a high cycling stability with 95% capacitance retention after 20 000 cycles at 20 A g -1 and an energy density of 4.5 W h kg -1 at a power density of 12.5 kW kg -1 in 6 mol L -1 KOH electrolyte. As a CO 2 adsorbent, N, O-PC-CNTs exhibited a high CO 2 uptake of 5.7 and 3.7 mmol g -1 at 1 bar at 273 and 298 K, respectively. Moreover, N, O-PC-CNTs showed cycling stability with 94% retention of the initial CO 2 adsorption capacity at 298 K over 10 cycles. This report introduces a strategy to design a coal based porous carbon composite for use in efficient supercapacitor electrodes and CO 2 adsorbents., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)