CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Hanqi Xu,Dexiang Li,Ruiwen Luo,Yujun Zhao,Hongjiu Su
The exceptional characteristics of mullite render it a significant candidate for application across several domains. However, finding ways to lower the synthesis temperature of mullite without compromising its purity has been an acknowledged challenge. In this work, we synthesized colloidal mullite precursors featuring a composite structure via ion exchange method and hydrolytic precipitation reaction of hydroxyl-aluminum chloride and effectively prepared high-content mullite materials at low temperatures. The crystalline phase transformations of the composite precursors with varying abundances of aluminum and silicon atoms during the calcination process were examined using X-ray diffraction and thermal analyzer techniques. The silicon-rich precursor was observed to form the mullite phase at 550 °C, with a mullitization rate of approximately 20.08 wt%. In addition, the molecular characterization of the calcined samples, utilizing nuclear magnetic resonance to analyze the near-neighborhood environment and X-ray photoelectron spectroscopy to elucidate surface structure, revealed that no substantial structural rearrangement occurs in the Si-rich samples as the calcination temperature increases. More aluminum and silicon atoms form a homogeneous structure and contribute to the mullite crystallization process. Based on the provided characterization analyses, it is plausible to deduce that the low-temperature crystallization of mullite is associated with the significant mixing of Al and Si species in the precursor at the atomic level. More specifically, the abundance of amorphous silica particles in the Si-rich samples facilitates the formation of massive mullite-like Si-O-Al bonds with aluminum, owing to its migratory and viscous deformation characteristics. Therefore, during the calcination process, the grains begin to grow exponentially through the grain boundary migration mechanism once the crystallization of the mullite phase is complete.
研究领域:
材料科学
·
无机化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 72
·58107-58115
·
IF 3.84
Wenbo Wang,Zhifang Zhang,Guangyan Tian,Aiqin Wang
The structural evolution of silicate opens a new avenue to cognize its microstructure, intensify its properties and extend its application. Herein, the one-step transformation of palygorskite (PAL) nanorods into smectite nanosheets was successfully achieved under mild hydrothermal condition with no addition of any extra chemicals. The structural evolution of PAL at different reaction stages and the change in physico-chemical characteristics was intensively studied through field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetry (TG) and Fourier transform infrared spectroscopy (FTIR) techniques. The key factors determining the transformation process were clarified. It was found that the moderate mechanical grinding, pH values and the existence of dolomite are essential to realize the transformation, and alkaline condition may facilitate the transformation. The transformation from nanorods to nanosheets is a rebuilding process of crystals, and the c/2 slide of tetrahedrons represents the main transformation mechanism. After the hydrothermal process, the adsorption capability of RPAL for Cu(II) evidently enhanced by 167%, and 99.01% of Cu(II) ions (only 64.9% for raw PAL) can be removed from 20 mg L−1 of Cu(II) solution.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2025
·
IF 9.2
Xianda Li,Zhongping Shao,Haozhe Shan,Li Liu
Cellulose utilization has been seriously hindered by the formation of humins, whereas humins structure remains challenging since unconverted cellulose and humins exist as solid mixture. In this work, we developed a novel strategy to extract humins from unconverted cellulose and disclosed the structural evolution process of cellulose-derived humins for the first time. The key intermediate of levoglucosan was successfully captured and identified, which significantly favors the formation of anhydro-sugars followed by polymerization due to the stability. By means of comprehensive HPLC-MS/MS, FT-IR, MALDI-TOF and SEM characterizations, it was proposed that multiple elementary reactions were involved in the formation of cellulose-derived humins, including cellulose depolymerization, etherification, esterification, aldol condensation, dehydration and thermal oxidation. In the early stage, cellulose depolymerization results in glucose and levoglucosan (LG), which undertake etherification to form the early humins via small molecule mechanism, accompanied by esterification and dehydration. In the later stage, gluco-oligosaccharides esp. with LG end from cellulose depolymerization undergo etherification via oligomer mechanism. Meanwhile, etherification of HMF and aldol condensation with LA take place prominently, together with dehydration and oxidation, resulting in the enhancement of C=C and C=O conjugation.
研究领域:
生物化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Leyao Xiong,Gaoming Mo,Ke Chen,Qing Huang
Ti 3 SiC 2 is a representative MAX phase that uniquely combines the merits of metals and ceramics. However, polymer-derived Ti 3 SiC 2 has been less extensively studied, especially in terms of its reaction mechanism and structural evolution. In this study, Ti 3 SiC 2 is synthesized by pressureless pyrolysis of PCS and TiH 2 , the structural evolution and chemical reactions occurring during the organic-inorganic conversion and synthesis process are investigated. The results show that Ti 3 SiC 2 with a mass fraction of 79.2 % can be achieved by pressureless pyrolysis of PCS and TiH 2 powders, with a Ti-to-Si atomic ratio of 3:1.7, at 1350 ℃. The presence of TiH 2 enhances the ceramic yield of PCS at 1000 ℃ compared to pure PCS, as some branched and crosslinking structures form between 100 ℃ and 300 ℃. By 800 ℃, the organic-inorganic conversion of PCS and the decomposition of TiH 2 are complete, resulting in the formation of amorphous SiC, free C and porous Ti. Concurrently, some SiC may transform into amorphous Si and C in the presence of porous Ti. At 1000 ℃, T 5 Si 3 forms within the porous Ti matrix, while TiC is generated on the periphery. Between 1200℃ and 1350 ℃, a reaction between these two phases and free C leads to the synthesis of Ti 3 SiC 2 . The formed Ti 3 SiC 2 phase begins to decompose at 1450 ℃ and completely breaks down into TiC, SiC, and TiSi 2 at 1600 ℃.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Juan Liu,Jingping Zhong,Zhiwen Chen,Jinshui Mao,Jun Liu,Zhenyu Zhang,Xiaocheng Li,Sili Ren
Attapulgite (AT) nanorods are generally regarded as one-dimensional materials and have been widely used in many fields. Two-dimensional (2D) AT nanomaterials have remained quite rare due to the difficulty of assembling from one-dimensional nanorods. Herein, we have prepared a novel type of single-layered 2D palmate AT nanosheets (AT-NS) with uniform size by a solvothermal synthesis process. The morphology and structure of the obtained 2D nanosheets were characterized by SEM, TEM, AFM, XRD, FTIR, and XPS. It was found that the AT nanosheets have a mean thickness in the range of 30–50 nm, and the length and width are in the range of 30 nm-2 μm. The structure evolution from AT nanorods to nanosheets were systematically studied and revealed. It was shown that the amination of AT and the introduction of trivalent iron ions (Fe 3+ ) ions into the AT materials play key roles in the formation of AT-NS. The AT nanorods are connected each other by the AT-NH 2 groups coupling with the Fe 3+ ions on the AT surface. More importantly, the Fe 3+ substitute the Al 3+ , Mg 2+ in AT mainly along the (1 1 0) planes. Therefore, the coordination of trivalent iron ions with amino groups occurs on the AT (1 1 0) plane. As a result, multiple nanorods are connected side by side to form the 2D nanosheets in a palmate shape. It is believed that the special morphology and structure of the 2D AT-NS material may bring some outstanding performance, which makes it have potential important application such as the demulsification of crude oil-in-water emulsion. In addition, the confined 2D assembling methodology offers us a new way to design and prepare novel materials with 2D structure.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ChemCatChem
·
2025
·
IF 3.9
Jingrong Li,Tingting Xiao,Xinluona Su,Qihang Gong,Peikai Luo,Jian Li,Haiyang Cheng,Fengyu Zhao
Graphical The evolution of the geometric structure and electronic states of Pd species was revealed for Pd/C catalysts in catalyzing the dehydrogenation of 12H-NECZ. The oxidized Pd δ+ species was reduced to Pd 0 species with finely-dispersed on the surface of support to generate H 2 with a high efficiency of 98.3%. The dehydrogenation of liquid organic hydrogen carriers is of significant potential for hydrogen energy applications. We successfully synthesized a highly efficient and stable Pd/C catalyst featuring ultrasmall (2.22 nm) and stable Pd nanoparticles via the deposition–precipitation method for the dehydrogenation of dodecahydro- N -ethylcarbazole. Interestingly, the Pd structure evolves during the reaction, with the Pd 2+ species on Pd/C catalyst re-dispersing into uniformly small-sized Pd 0 nanoparticle under reaction conditions. The conventional thermal treatment of calcination–reduction typically results in larger Pd particles due to the stronger metal-support interaction. Kinetic studies revealed the oxidation state of Pd 2+ species (Pd(OH) 2 , PdO) is more active for the dehydrogenation reaction compared to the metallic state Pd 0 species. The in situ structure evolution induced ultrasmall Pd nanoparticles (2.22 nm) with a constant Pd 0 /Pd 2+ ratio, achieving a high efficiency (98.3%) of H 2 release from 12H-NECZ dehydrogenation at 180 °C. This work provides a simple method for preparing highly dispersed Pd/C catalyst with stable ultrasmall Pd particles, offering valuable insights to researchers in the field of supported metal catalysts.
研究领域:
催化化学
·
材料科学
·
能源化学
✓ 已验证
DOI
高影响因子
VACUUM
·
2024
·
IF 3.8
Ping-guo Jiang,Xiong-gang Lu,Wang-jun Peng,Hong Liu,Yao Zhu,Cai-song Yan,Jing-rong Zhao
This study investigates the structural evolution of blue tungsten reduction products when exposed to hydrogen under controlled water vapor partial pressures. The reduction of WO₂.₉ was achieved through hydrogen atom diffusion at 1050 °C. The Results indicate that, at low water vapor partial pressure, the reduction process of blue tungsten initiates on the surface and progresses inward, creating surface cracks on the clusters. These cracks enable water vapor to interact with the reduced tungsten (W) at their base, leading to the formation of needle-like WO₂.₇₂ phases that grow outward. Under high water vapor partial pressure, the morphology of the acicular WO 2.72 phase changes to a stacked structure. Additionally, W-OH bonds were identified in the reduction products, with the WO₂.₇₂ growth angles observed at approximately 12° relative to the tungsten particles, closely matching the interfacial model prediction of 13.41°. The results of this paper will provide theoretical support for the structural evolution of intermediate products during hydrogen reduction of blue tungsten.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Yantong Lu,Guangshe Li,Sixian Fu,Shaofan Fang,Liping Li
CsCu2I3 mixed with Cs3Cu2I5 has shown potential applications as white-light-emitting materials, while their growth, structural evolution behaviors, and their impact on photoluminescence of CsCu2I3 nanocrystals (NCs) are still not known. In this work, we investigated the growth and structural evolution of CsCu2I3 nanocrystals with increasing reaction temperature. At low temperature and in the presence of a high dosage of oleic acid and oleylamine, Cs3Cu2I5 nanoparticles, rather than CsCu2I3 NCs, preferred to form in the hot-injection reaction system. Increasing the reaction temperature promoted the formation of CsCu2I3 nanorods. Phase-pure CsCu2I3 nanorods were steadily obtained at 180 °C. Structural evolution from less copper-containing NCs to copper-rich ones in the low-temperature reaction condition is highly related to the coordination of copper ions with OAm. More importantly, accompanying the growth of nanorods and structural evolution from Cu3Cs2I5 to CsCu2I3, the color of photoluminescence emission of NCs changed from blue to nearly white and to yellow, but their photoluminescence quantum yield decreased from 36.00 to 9.86%. The finding in this work would give a view to the structural evolution of copper-containing perovskite-like halides, being helpful for adjusting their photoluminescence in white LEDs.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2018
·Vol. 20
·期 44
·28176-28184
·
IF 3.906
Jianfeng Jia,Shaorui Chen,Qianwen Yang,Xiang Feng,De Li
LiBC is a layered boron carbide material that was first studied as a superconducting material. Theoretical study showed that LiBC is a promising cathode material in Li-ion batteries, while our early computational and experimental studies demonstrated the feasibility of LiBC as a high-capacity anode material for Li-ion batteries. In this work, LiBC has been synthesized by a solid-state method using different carbon precursors of acetylene black and graphite, marked a-LiBC and g-LiBC, respectively, and their electrochemical properties and corresponding structure evolutions have been investigated in Li-ion batteries. As a result, a-LiBC delivers a higher specific capacity than g-LiBC, 500 mA h g−1vs. 200 mA h g−1, after 50 cycles at a rate of 0.1C. Actually, a significant structural evolution of a-LiBC was observed by in situ XRD during the charge/discharge processes, while a nearly constant structure was detected for g-LiBC. Meanwhile, in situ Raman results revealed the evolution of vibrational beating modes at different charge/discharge states. Therefore, the specific capacity of LiBC is closely related to its crystallinity, and LiBC with amorphous carbon precursors could be adopted as a promising anode material for Li-ion batteries.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Yu Sun,Juan Liu,Tulai Sun,Zilong Yu,Ziyang Zheng,Mengru Ge,Lihong Bai
In this study, multiple rare earth elements were introduced to modify the multiferroic properties of BiFeO 3 . The effects of co-substitution on the structural evolution and properties were thoroughly investigated. With increasing substitution content, the ceramics underwent a symmetry transition from R 3 c to Pna 2 1 and finally to Pbnm . Co-substitution significantly enhanced the ferroelectric properties, with the highest remanent polarization of 33.14 μC/cm² observed at x = 0.10. Due to the symmetry evolution, ferromagnetism was released from the cycloidal spin structure, and the hysteresis loop gradually saturated, with the highest remanent magnetization ( M r ) of 0.25 emu/g observed at x = 0.16. The concurrent improvement in ferroelectricity and ferromagnetism resulted in substantial magnetoelectric coupling performance, with α ME = 3.50 mV/(cm·Oe). Moreover, direct current poling significantly induced the reverse transition from R 3 c to Pna 2 1 , indicating the potential for electrically controlled magnetism. This study provides a new perspective for modifying the magnetoelectric properties of BiFeO 3 .
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2025
·
IF 7.3
Changzu Zhu,Tao Jiang,Shilin Jiang,Xinyu Zhang,Ming Cheng,Wentao Zhou,Wei-qun Shi,Yafei Wang
Electrochemical separation of spent fuel utilizing molten salt as a medium is an efficient approach to achieve the sustainable development of nuclear energy. The Lewis acidity and basicity of molten salts are closely related to the local structure of the molten salt and significantly influence its properties. In this study, the acidity–basicity scales of LiCl–KCl–CsCl–LaCl3 molten salts have been quantitatively determined using in situ UV–vis spectrophotometry with Tl+ probes, and the relationship between the acidity–basicity scale and temperature was deduced. The influence of molten salt’s acidity–basicity scale on its structural evolution was investigated through Deep Potential Molecular Dynamics (DPMD) simulations and in situ Raman spectroscopy. As the acidity–basicity scale of molten salt increases, the short-range ordering of the melt diminishes, and the intermediate-range ordering enhances. Moreover, based on the accumulation of data at various temperatures, the relationships between the temperature-dependent acidity–basicity scale and the thermal transport properties were derived. The reduction potential of La was analyzed through electrochemical tests to evaluate the corrosiveness of the salt melt, and it was found that molten salt with a higher acidity–basicity scale exhibited greater corrosivity. This study elucidates the correlation of the acidity–basicity scale with salt structure and properties, providing an effective method for comprehensive assessment and real-time monitoring of salt structure and properties through the direct measurement of the salt acidity–basicity scale.
研究领域:
核能化学
·
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
·
IF 5.4
Xuejiao Liu,Beibei Pan,Zhiwei Li,Poonnawit Hanphaiboon,Yin Wang
Activated carbon supported nanoscale zero-valent iron (NZVI/AC) has been proved to be versatile for removing several kinds of contaminants from environmental matrix. The structural properties of NZVI/AC composites play a crucial role in determining both the decontamination efficiency and adsorption capacity of these materials. However, studies relevant to structural evolution and corresponding manipulation routes for AC-supported NZVI are still scarce. Herein, AC-supported NZVI were prepared under different synthesis conditions followed by characterizing them using several techniques and evaluating their reactivity toward heavy metal in aqueous solution. NZVI/AC synthesized under different molecular weight of PEG and m AC :m Fe possessed a similar removal efficiencies of Pb(II) from aqueous solution, meanwhile, NZVI/AC synthesized with a suitably prolonged time at n BH4 :n Fe = 8.0 exhibited obvious enhancement for Pb(II) removal from aqueous solution. As for structural evolution of AC-supported NZVI, results show that the crystallization was more complete, the shape was converted from needle to sphere, the particle size was becoming smaller, the particle distribution was more homogeneous, the specific surface area was smaller, and the surface oxidation was lower as suitably increasing m AC :m Fe , n BH4 :n Fe , and reaction time. The size and density of iron precursor by complexation of PEG and Fe 2+ , and ratio of nuclei formation to growth values are essentially responsible for manipulating structure of AC-supported NZVI. Spherical AC-supported NZVI with higher iron content based on smaller particle size, uniform distribution, and lower surface oxidation in one is responsible for significant enhancement of Pb(II) removal rate and capacity thanks to higher surface reactivity, more accessible surface-active sites, and faster electron transfer from core to shell of iron. This study would provide a new insight into comprehending manipulation mechanism for the key structure of AC-supported NZVI composites for aquatic remediation.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）