Nanoscale
·
2024
·
IF 5.8
Heyun Lin,Wenzhe Zhang,Huachen Shen,Hailing Yu,Yunlei An,Tiejun Lin,Liangshu Zhong
The catalytic behavior of CO hydrogenation can be modulated by metal–support interactions, while the role of the support remains elusive. Herein, we demonstrate that the presence of strong metal–support interactions (SMSI) depends strongly on the crystal phase of TiO2 (rutile or anatase) and the treatment conditions for the TiO2 support, which could critically control the activity and selectivity of Ru-based nanocatalysts for CO hydrogenation. High CO conversion and olefin selectivity were observed for Ru/rutile-TiO2 (Ru/r-TiO2), while catalysts supported by anatase (a-TiO2) showed almost no activity. Characterization confirmed that the SMSI effect could be neglected for Ru/r-TiO2, while it is dominant on Ru/a-TiO2 after reduction at 300 °C, resulting in the coverage of Ru nanoparticles by TiOx overlayers. Such SMSI could be suppressed by H2 treatment of the a-TiO2 support and the catalytic activity of the as-obtained Ru/a-TiO2(H2) can be greatly elevated from almost inactive to >50% CO conversion with >60% olefin selectivity. Further results indicated that the surface reducibility of the TiO2 support determines the SMSI state and catalytic performance of Ru/TiO2 in the CO hydrogenation reaction. This work offers an effective strategy to design efficient catalysts for the FTO reaction by regulating the crystal phase of the support.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Songshan Zhu,Shimin Ma,Di Song,Yunzhu Wang,Jichang Lu,Tianhao Ai,Huihui Lu,Sufang He,Yongming Luo
The dynamic relationship of TiO 2 crystal phase and strong metal-support interactions (SMSI) of Ni/TiO 2 catalyst was investigated to reveal the induction period of glycerol steam reforming. Comprehensive investigations confirmed that the SMSI between Ni 0 and anatase TiO 2 was formed by anatase TiO 2 encapsulated Ni 0 after H 2 reduction at 500 °C for the Ni/TiO 2 catalyst calcined at 500 °C (Ni/Ti-500R), which inhibited the contact of Ni 0 active sites with reactants and led to the low hydrogen yield in the initial stage of the reaction. Interestingly, the dynamic conversion of anatase to rutile during the GSR process at 600 °C caused the TiO 2 overlayers on the Ni 0 particles to gradually fade, exposing more Ni 0 sites, resulting in a gradual increase in hydrogen yield to 5.93 mol H2 /mol glycerol . In addition, Ni/Ti-500R with a dynamic SMSI inhibited Ni 0 particles sintering and encapsulated carbon deposition, resulting in relatively better stability (21 h) after induction period. In comparison, the designed Ni/TiO 2 catalyst calcined at 600 °C (Ni/Ti-600R) with rutile TiO 2 as the main component inhibited the formation of the classical SMSI, even after 600 °C H 2 reduction, and no excessive TiO 2 encapsulated Ni 0 particles were observed, so no obvious induction period occurred. This study provides new insights into the relationship of SMSI with crystal phases and the induction period in multiphase catalysis, also a new strategy for designing efficient catalysts.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2023
·
IF 7.3
Hao Xu,Hao Li
Constructing heterogeneous catalysts with high efficiency and stability to achieve biomass HDO under comparatively mild conditions is an arduous challenge. Crystal phase of metal oxides supports could affect the geometric and electronic properties, causing the variation of catalytic performance. Herein, a series of Pd/Nb 2 O 5 catalysts of pseudohexagonal crystal phase (Nb 2 O 5 -TT), orthorhombic phase (Nb 2 O 5 -T) and monoclinic phase (Nb 2 O 5 -H) are prepared through regulating the annealing temperature. Impressively, Pd/Nb 2 O 5 -T catalyst showed amazing catalytic performance of 100% conversion and 98.9% selectivity of 2-methoxy-4-methylphenol (MMP) at room temperature (25℃) within 30 min, superior than Pd/Nb 2 O 5 -TT, Pd/Nb 2 O 5 -H and other Pd-based catalysts that had been reported. Besides, the Pd/Nb 2 O 5 -T perform robust stability and maintain its high activity after ten times recovery experiment. This catalytic system is also suitable for different kinds of aldehydes compounds at room temperature, exhibiting the high activity and selectivity towards deoxygenated products. Based on the characterizations and experimental validations, it has confirmed that the strong metal-support interaction (SMSI) effect generates via electron transfer between Pd species and Nb 2 O 5 -T support, where in situ reduction of PdO occurred during the reaction, generating active interfacial Pd-O-Nb sites and accelerating the breaking of C-O bonds. The insights of this work provide a guiding direction for the future design of highly selective heterogeneous catalysts by crystal phase modulation engineering.
研究领域:
催化化学
·
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
HYDROMETALLURGY
·
2014
·
IF 2.224
Mohannad Mayyas,Mohammad Al-Harahsheh,Xian-Yong Wei
Jordanian phosphate ore contains 70–150 parts per million (ppm) uranium. The uranium in the ore tends to dissolve during the leaching of phosphate ore with sulfuric acid to produce phosphoric acid (PA). Solvent extraction (SX) using various extracting agents is widely used to extract uranium from PA. Meanwhile, much research work has been carried out to develop suitable solid phase extractants in order to reduce cost and enhance efficiency. In this study, a new solid phase extractant has been synthesized by anchoring 2-hydroxy-4-aminotriazine onto activated carbon (ACH). The extraction of uranium from Jordanian PA using ACH and the synergistic mixture of di-ethylhexyl phosphoric acid and trioctyl phosphine oxide (DEPA–TOPO) diluted in kerosene were investigated and the performance of each extractant was evaluated and compared. The results showed that 91% extraction and 559.9 ppm loading capacity were achieved after 2 to 3 min mixing time using 0.5 M DEPA–0.125 M TOPO at 20 °C, 410 mV and 1/1 phase ratio. The activation energy ( E a ) of the solvent extraction (− 26.03 kJ mol − 1 ), calculated from Arrhenius plot, indicates that the reaction is barrier-less and exothermic in nature. On the other hand, uranium sorption onto ACH reaches equilibrium after 10 min and about 92% extraction can be achieved at 20 °C, C o = 70 mg/l, V = 200 ml, W = 100 mg and 410 mV; the rate constant for the uranium sorption onto ACH (16.54 × 10 − 3 g mg − 1 min − 1 ) was calculated from the pseudo-second order equation. The countercurrent extraction results showed that ACH has high physical, chemical stability and loading capacity about 618 mg g − 1 . Thermodynamic parameters ( ΔH ads ° = 20.61 kJ mol − 1 , ΔS ads ° = 160.47 J mol − 1 K − 1 , ΔG ads ° (333.3 K) = − 32.87 kJ mol − 1 ) suggest that the adsorption is endothermic and spontaneous in nature, which confirm the feasibility of the process.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Case Studies in Thermal Engineering
·
2021
·
IF 4.724
Jing Fan,Han Mu,Chang Gao,Fenhong Song
Recently, biodiesel is considered as a biodegradable, renewable and high-potential fuel which could be used directly in tradition internal combustion engines. Fuel’ transport properties in high pressure are required to model the process of fuel spray, atomization and combustion accurately. This work, three ethyl esters’ liquid thermal conductivity (biodiesel compounds) in the liquid phase was measured by an experiment system which is established based on a transient hot-wire method with a bare platinum hot wire. The measurements were conducted at the temperatures ranging from 292 K to 372 K and pressure up to 15 MPa. The combined expanded uncertainty of the measurement was estimated to be ±2.0% (in the 0.95 confidence level). For interpolation, the relationship between measured results with temperature and pressure were correlated as a polynomial function, and the maximum deviation of correlations were less than 0.30%.
研究领域:
能源科学
·
物理化学
✓ 已验证
DOI
高影响因子
Nanomaterials
·
2024
·
IF 4.4
Caide Fan,Jialu Lu,Chengjie Duan,Chengbin Wu,Jiming Lin,Ruoxiang Qiu,Zehui Zhang,Jianming Yang,Bin Zhou,Ai Du
Silica aerogels exhibit a unique nanostructure with low thermal conductivity and low density, making them attractive materials for thermal isolation under extreme conditions. The TiO 2 particle is one of the common industrial additives used to reduce the thermal radiation of aerogel composites under high-temperature environments, but its influence on thermal resistance is almost unknown. Herein, we report the effect of TiO 2 nanoparticles with different crystal phases and different sizes on the thermal stability of silica aerogel composites. By adding TiO 2 nanoparticles, the aerogel can significantly resist collapse at high temperatures (up to 1000 °C). And compared with the rutile phase TiO 2 , the anatase phase TiO 2 shows much higher temperature resistance performance, with shrinkage of only one-sixth of the rutile phase after 800 °C treatment. Interestingly, energy-dispersive spectrometer mapping results show that after 800 °C treatment, silica nanoparticles (NPs) are squeezed out in between anatase TiO 2 particles, which resists the coarsening of silica NPs and ultimately enhances the stability of aerogel composites. The optimal anatase phase TiO 2 -doped silica aerogel demonstrates the integrated properties of crack-free morphology (2.84% shrinkage), low thermal conductivity (29.30 mW/(m·K)) and low density (149.4 mg/cm 3 ) after 800 °C treatment. This study may provide new insights for developing oxide-doped silica aerogels with both high-temperature resistance and low thermal radiation.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2015
·Vol. 44
·期 19
·9251-9259
·
IF 4.197
Aiwei Tang,Zunlan Hu,Zhe Yin,Haihang Ye,Chunhe Yang,Feng Teng
A simple one-pot colloidal method has been described to engineer ternary CuInS2 nanocrystals with different crystal phases and morphologies, in which dodecanethiol is chosen as the sulfur source and the capping ligands. By a careful choice of the anions in the metal precursors and manipulation of the reaction conditions including the reactant molar ratios and the reaction temperature, CuInS2 nanocrystals with chalcopyrite, zincblende and wurtzite phases have been successfully synthesized. The type of anion in the metal precursors has been found to be essential for determining the crystal phase and morphology of the as-obtained CuInS2 nanocrystals. In particular, the presence of Cl− ions plays an important role in the formation of CuInS2 nanoplates with a wurtzite–zincblende polytypism structure. In addition, the molar ratios of Cu to In precursors have a significant effect on the crystal phase and morphology, and the intermediate Cu2S–CuInS2 heteronanostructures are formed which are critical for the anisotropic growth of CuInS2 nanocrystals. Furthermore, the optical absorption results of the as-obtained CuInS2 nanocrystals exhibit a strong dependence on the crystal phase and size.
研究领域:
材料科学
·
纳米技术
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Virtual and Physical Prototyping
·
2025
·
IF 8.8
Wei Chen,Lianyong Xu,Wenchun Jiang,Danyang Lin
In this work, we demonstrate a phase engineering strategy, based on a composite design of monomorphic diamond (MD) reinforced FV520B maraging steel, for controlling matrix phase constituents with high strength and ductility. Benefiting from the enhanced grain growth rate induced by the MD addition, the solidification structure transition from planar to cellular and further to dendritic was achieved. The dissolved MD solute modifies the martensite-to-austenite transformation kinetics, promoting the stabilisation of a predominantly austenitic phase structure. Meanwhile, the elemental segregation around the cellular structure contributes to the massive formation of the M23C6 carbides. Consequently, the microstructural changes due to the MD particle addition result in an exceptional synergy of strength and ductility. This work provides a promising way to fabricate dispersion-strengthened maraging steels with high overall performance.
研究领域:
材料科学
·
冶金学
·
机械工程
·
复合材料
·
相变
✓ 已验证
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2024
·
IF 5.9
Shixiong Chen,Jiarong Wang,Jing Zhang,Qinghao Zeng,Hong Jiang,Haiqing Chang,Tian C. Zhang,Xiaobao Tian,Kai Wang,Ying Liang
Surface modification could remarkably improve the oil–water separation ability of membrane, but suffers from limited survival positive effect layer after long-term operation. Herein, we report a systematic comparative study between bulk and surface modification (i.e., synchronous or sequential electrospun/elecrospraying) on hydrophobic polyvinylidene difluoride (PVDF) membrane. A hydrophilic UiO-66-NH 2 @polyacrylic acid micro/nanospheres (UiO@PAA) was selected as functional layer to improve the separation and adsorption capability of PVDF. The surface modification (SMM) and bulk modification membranes (BMM) exhibited the similar water wetting behavior in air as the same surface layer. The spider filament-like nanofibers of BMM could enhance the mechanical stability and dispersion uniformity of active sites among the PVDF fibers. In terms of oil-in-water emulsions separation ability, the BMM was superior to the SMM with the maximumly increase of separation efficiency and filtration flux to 1.3 % and 192.6 L m -2 h −1 , respectively. As for dye absorption, the BMM showed better adsorption capacity with a removal efficiency over 96 %. For the low concentration of methylene blue, the removal efficiency of SMM was only 94 %, while the removal efficiency of the BMM reached 98 % at room temperature. In addition, the BMM exhibited higher removal efficiency over 94 % compared with that less than 84 % of SMM after eight cycling tests, confirming its advantages in repeatability. This study demonstrates that the bulk modification can endow the initial membrane with better performance and durability, showing more promising prospects in actual wastewater treatment.
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
DESALINATION
·
2024
·
IF 8.3
Yue Zhao,Shan Ni,Yafeng Liu,Wenjie Wang,Yuan Meng,Huifang Xing,Huizhou Liu,Liangrong Yang
To address the environmental and resource challenges arising from the advancement of the nuclear power industry, it becomes imperative to foster the development of efficient and expeditious materials for uranium adsorption. Here, for the first time, a kind of niobium phosphate with improvement of interlayer spacing and hydrophilicity (NbP-8) is employed by crystal phase modulation for uranium adsorption, which synergistically realizes structural and interfacial microenvironment modulation. Characterizations demonstrate that the expanded interlayer spacing contributes to accommodation of uranyl which increases adsorption capacity, and the enhanced hydrophilicity reduces infiltration time and greatly accelerates the adsorption rate. Consequently, NbP-8 possesses exceptional adsorption capacity of 1470.4 mg g −1 , ultra-fast adsorption rate with an equilibrium time of 1 min and high selectivity, delivering one of the best phosphate uranium adsorbents. Moreover, this work opens a new venue for optimizing performance of phosphate by changing the crystal phase to modulate structure and interfacial microenvironment for uranium adsorption.
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
JOM
·
2025
·
IF 2.3
Chen Jialin,An Ming,Dai Mengnan,Li Shutao,Chen Yeqing,Song Rui,Song Jiaxing,Chen Longming,Zhong Xiting,Tian Quanwei
The properties of oxidants significantly affect the thermal and combustion properties of nanothermites, and alpha and beta-MnO 2 nanorods with similar morphological appearances were prepared using the hydrothermal method. Corresponding nanothermites were prepared employing the electrostatic spraying method and their thermal and combustion properties have been compared through TG-DSC and combustion tests. The aluminothermic reaction process was simulated by molecular dynamics, and the results showed that the β-MnO 2 /Al nanothermite first underwent β-MnO 2 thermal decomposition followed immediately by an aluminothermic reaction, whereas the α-MnO 2 /Al nanothermite underwent a direct aluminothermic reaction. In contrast, the α-MnO 2 /Al nanothermite could release more heat. According to thermal analysis, the activation energy of α-MnO 2 /Al nanothermite was 100.15 kJ mol − 1 higher than β-MnO 2 /Al nanothermite, indicating better stability. Combustion experiments showed that the combustion propagation rate of the α-MnO 2 /Al nanothermite was faster than the β-MnO 2 /Al nanothermite. The results have been verified and the reaction process has been exhibited using molecular dynamics to simulate the aluminothermic reaction process. The notable differences in the thermal and combustion properties of nanothermites containing MnO 2 with varying phases can be attributed to the distinct crystal structures of α-MnO 2 and β-MnO 2 . The alternating 1 × 1 and 2 × 2 tunnel structure of α-MnO 2 is more stable, whereas β-MnO 2 undergoes thermal decomposition before the aluminothermic reaction.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2018
·
IF 2.524
Weimin Li,Faqin Dong,Liang Bian,Hao Zou,Mianxin Song
In this study, Ce-doped zirconolite was synthesized through high-temperature solid-state reaction at 1250 °C in air for 96 h. The crystal phase, microstructure and valence transition were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Phase relations of CaZr 1– x Ce x Ti 2 O 7 systems were determined by XRD analyses and Rietveld refinements . Four different phases are identified, namely zirconolite, perovskite , pyrochlore, and cerianite. The phase transformation (2M-zirconolite → 4M-zirconolite → Ce-pyrochlore) is caused by cations rearrangement as cerium content increases. The solubility limit of cerium ions in CaZr 1– x Ce x Ti 2 O 7 system is estimated to be approximately 0.80. Under sintering air atmosphere, partial reduction of Ce 4+ in Ce 3+ is detected in Ce 3d XPS spectra, and the ratio of Ce 3+ and Ce 4+ significantly decreases as cerium content increases.
研究领域:
材料科学
·
化学
✓ 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）