Catalysis Science & Technology
·
2025
·
IF 4.2
Dajian Li,Alfin Kurniawan,Tania Roy,Jin Wang,Cheng lan Liu,Ze Zhen Wang,Rong Zhen Mu,Chun Hui Zhou
The efficient production of allyl alcohol from glycerol is of great importance due to its significance as a valuable intermediate in chemical industries. While catalytic conversion of glycerol to allyl alcohol by solid acid catalysts, carbon deposition (coking) is prone to occur on the catalyst surface, leading to slow down the conversion process and fast deactivation of the catalyst. In this study, we obtained an efficient catalyst for the preparation of allyl alcohol from gas-phase glycerol by controlling the pore structure and surface acidity of the catalyst. The characterization results showed that hydrochloric acid and citric acid removed the silicon and aluminium elements from montmorillonite, and the acidity, pore volume, and surface area ratio of Na-MMT (SBET=34.5 m2 g-1, VT=0.19 cm3 g-1) of the porous montmorillonite(HA1MMT) catalyst were all improved (SBET=97.9 m2 g-1, VT=0.28 cm3 g-1); After adding MoOx and VOx, the selectivity of Mo/V-HA1MMT catalyst for allyl alcohol was improved. The XPS characterization results indicate that the synergistic effect of Mo and V can promote the transfer of electrons during the reaction process of glycerol conversion. Within 480 minutes of catalyzing glycerol dehydration reaction, Mo0.6V0.4(5)-HA1MMT was almost deactivated (Conv.= 19.5%, Sel.allyl alcohol=31.2%) due to carbon deposition. When the catalyst was doped with calcium and magnesium components, a new active phase CaMo4 was discovered on the catalyst, and the acidity of Ca0.5Mg0.5-Cat. (Cat. is Mo0.6V0.4(5)-HA1MMT) decreased to 214.0 μmol g-1. The coking resistance performance of Ca0.5Mg0.5-Cat. was improved, and after 660 minutes of reaction, the catalyst was deactivated (Conv.= 32.1%, Sel.allyl alcohol=30.1%) due to carbon deposition. During the 3rd catalyst regeneration test, Ca0.5Mg0.5-Cat. still maintained high activity (Conv.= 63.3%, Sel.allyl alcohol=35.2%, Sel.acrolein=31.2%). The results of this study indicate that suitable pore structure and acidity are crucial for designing a catalyst with coking resistance properties.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2021
·
IF 5.645
Xiaoxu Yang,Shiyao Hou,Tingting Chu,Jiazhi Han,Runsen Li,Yanzhu Guo,Yumei Gong,Haiming Li,Zhiwei Wan
Eco-friendly, renewable and green biomass materials are considered as the superior carbon precursors for producing carbon quantum dots (CQDs) in large scale. A major challenge is the limited contents of fluorophores in biomass, which then results in low quantum yields (QYs) and inferior fluorescence emission ability of the obtained CQDs. Herein, lignin with amounts of unsaturated aromatic and carbonyl fluorophores was employed as the carbon precursors to prepare CQDs through a green, facile approach. The magnesium and nitrogen elements were successfully introduced into CQDs with the aim of enhancing their QYs and extending their emission wavelengths. The prepared magnesium, nitrogen-doped CQDs (Mg, N-CQDs) could emit green fluorescence with a quantum yield (QYs) up to 46.38 %. The mechanism of their fluorescence ability was discussed extensively. More interestingly, the Mg, N-CQDs displayed a fluorescence transition between green and yellow color at pH value of 5.4, indicating their potential application as a probe to detect pH values of complicated environments. The findings in this paper would provide a viable strategy to converse lignin biomass waste into high-quality fluorescence nanomaterials.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Advanced Materials Interfaces
·
2020
·Vol. 8
·期 1
·2001606
·
IF 4.948
Zuohao Wen,Yujie Ke,Chengchen Feng,Shuliang Fang,Miuyang Sun,Xinghai Liu,Yi Long
The VO 2 -based smart windows can dynamically and reversibly adjust the indoor solar irradiation to reduce the energy consumption for building glasses. This paper reports the first successful preparation of Mg-doped VO 2 @ZrO 2 core−shell nanocrystals with promoted thermochromic performance as well as tunable appearance and wettability. The achieved combination of T lum of 52.4% and ∆ T sol of 7.1% is comparable to the best-reported results of VO 2 -based core−shell rod structures. The thickness of ZrO 2 shell is tunable between 3 and 14 nm, resulting in a slightly hydrophobic surface and a slight color change toward blue-green and brighter produced films. The preparation method based on hydrothermal and UV-curing methods is facile. This work may inspire future development of VO 2 synthesis, their structure−property, and the application the thermochromic films for energy-saving purposes in buildings or automobiles.
研究领域:
材料科学
·
能源技术
·
纳米技术
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 21
·18360-18369
·
IF 2.22
Wang Mengmeng,Tao Yueming,Zhang Dongyun,Sun Guanghan,Feng Ping,Chang Chengkang
Na 3–2 x Mg x V 2 (PO 4 ) 3 /C (0 ≤ x ≤ 0.2) were synthesized by a sol–gel method. According to X-ray diffraction (XRD) Rietveld refinement and energy dispersive spectroscopy (EDS) mapping results, Mg ions were approved to occupy the Na2 (18e) site in Na 3–2 x Mg x V 2 (PO 4 ) 3 /C for the first time. The amount of Mg substitution in Na 3–2 x Mg x V 2 (PO 4 ) 3 /C was optimized. The specific discharge capacities of Na 2.9 Mg 0.05 V 2 (PO 4 ) 3 /C at 10 C, 20 C, and 30 C were 98.9%, 91.5%, and 76.2% of the value obtained at 1 C, respectively. Na 2.9 Mg 0.05 V 2 (PO 4 ) 3 /C exhibited the highest capacity retention of 80.3% with a discharge capacity of 77.3 mAh·g −1 after 1200 cycles at 10 C. Na 2.9 Mg 0.05 V 2 (PO 4 ) 3 /C exhibited superior rate performance, resulting from a high sodium diffusion coefficient ( D Na ) of 3.91 × 10 –12 cm 2 ·s −1 and the excellent electrical conductivity (5.7 × 10 –2 s·cm −1 ). Combining the X-ray photoelectron spectroscopy (XPS) and Electrochemical impedance spectroscopy (EIS) results, the mechanism of Mg substitution was investigated. Since two Na + were replaced by one Mg 2+ , \({\mathrm{V}}_{\text{Na}}^{^{\prime}}\) was produced to maintain valence equilibrium. This phenomenon benefited Na + migration by broadening the diffusion channel in the structure of Na 3 V 2 (PO 4 ) 3 . According to the EPR results, the signal intensity of Na 2.9 Mg 0.05 V 2 (PO 4 ) 3 /C was much stronger than that of Na 3 V 2 (PO 4 ) 2 /C, thus confirming the existence of \({\mathrm{V}}_{\text{Na}}^{\mathrm{^{\prime}}}\) after Mg substitution. When the amount of Mg substitution was further increased to 0.1, the D Na decreased because of the small radius of Mg 2+ , which led to severe lattice distortion and volumetric shrinkage of the unit cell.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Wei Wang,Bo Jiang,Weiyi Xiong,Zhen Wang,Shuqiang Jiao
A nanoparticle Mg-doped Li 4 Ti 5 O 12 with a grain size of 20–30 nm has been successfully synthesized through a simple hydrothermal method . The first-principle simulations are employed to theoretically study the crystal structure, unit cell volume, lattice parameters , and band gaps. Galvanostatic charge–discharge tests have been carried out, using the as-prepared Li 4 Ti 5 O 12 and Mg-doped Li 4 Ti 5 O 12 as the working electrodes with a voltage range of 0.5–2.5 V vs. Li + /Li. The tests show promising results with high capacity and long term stability. When discharging at 350 mA g −1 (corresponding to a 2 C rate), the discharge capacity remains at 170 mAh g −1 over 100 cycles. As the C-rate rises to an ultrafast charge–discharge rate of 50 C, the discharge capacity can still retain at 115 mAh g −1 . The excellent electrochemical performance is due to both the nanomorphology and better conductivity after Mg doping. The results show that the Mg-doped Li 4 Ti 5 O 12 can act as a fast charge–discharge anode material for high rate lithium-ion batteries (LIBs).
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
HYDROMETALLURGY
·
2021
·
IF 4.156
Luri Bao,Jingze Zhang,Jie Wu,Guotai Zhang,Yang Yang,Weiping Tang,Mei Xue
Owing to the increasing global demand for lithium, extraction of lithium from salt lake brine water has received considerable attention. In this study, the magnesium doping to produce Li 1.6 Mg x Mn 1.6-x O 4 (LMMO) was designed to overcome the limitation caused by the loss of Mn due to dissolution. The chemical and morphological properties of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The XRD results confirmed that the crystal structure of Li 1.6 Mn 1.6 O 4 was retained after Mg-doping. Scanning electron microscopy and energy-dispersive X-ray spectroscopy showed that LMMO has a flake-shaped structure and the Mg 2+ ions were uniformly distributed in the precursor. The doping of Mg 2+ led to the decrease of Mn 3+ content in the precursor, improving its structural stability. The adsorption capacity of LMMO-6% was 35.6 mg g −1 , which was greater than that of the undoped sample (33.2 mg g −1 ). After the tenth cycle, the dissolution loss of Mn in LMMO-6% was 0.55%, and it is smaller than that for lithium manganese oxide (0.94%). Results confirm that the structural stability was improved compared to undoped adsorbents. Moreover, batch adsorption experiments demonstrated the potential of the HMMO-6% adsorbent to be used for lithium adsorption from real salt lake brine.
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
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Fuyun Li,Min Zeng,Jing Li,Hui Xu
Mg-doped Li4Ti5O12 nanoparticles with a grain size of around 200 nm were synthesized successfully using a simple solid-state reaction route. The effects of Mg 2+ doping on Li4Ti5O12 were systematically investigated by XRD, XPS, TEM, HRTEM and EDS. These indicated that Mg ions were uniformly dispersed into Li4Ti5O12 lattice and Mg 2+ doping during sintering can effectively inhibit the growth of Mg-doped Li4Ti5O 12 particles without changing the structure of Li4Ti5O 12 . The charge-discharge cycling tests and EIS analysis were conducted to study their electrochemical performance. The initial discharge capacity of the Mg-doped Li4Ti5O12 electrodes was 190mAhg -1 at 1 C and the discharge capcity of 179mAhg -1 was retained after 100 cycles. Moreover, the discharge capacity of 150mAhg -1 was maintained even at a high rate of 5 C after 100 cycles, whereas the undoped electrodes only exhibited a capacity of 134mAhg -1 under the same condition. The excellent electrochemical performance of doped electrodes can be ascribed to the unique properties of nanomaterials and excellent electrical conductivity due to Mg 2+ doping.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Manting Zeng,Xingzhong Liu,Hua Hao,Zhonghua Yao,Hanxing Liu
BaTiO 3 -1.6MnO 2 - x Er 2 O 3 ceramics (abbreviated as BMT- x Er) and BaTiO 3 -1.6MnO 2 -3Er 2 O 3 - x MgO ceramics (abbreviated as BEMT- x Mg) were prepared under a reducing atmosphere by solid-state synthesis method in this work. The effects of Er/Mg co-doping on phase transformation, microstructure, dielectric properties, and defect were systematically investigated. Research shows that Er-doping reduces the Curie temperature and increases the dielectric constant of BaTiO 3 ceramics at low temperatures. Mg-doping refines the grain size and makes the grain size distribution more uniform, which is an important reason for the enhanced bias stability. The substitution of Mg at the B-site generates additional oxygen vacancies which capture free electrons and simultaneously forms defect dipoles. The anti-reducing properties are improved by reducing the carrier concentration. The synergistic effect of co-doping forms defect dipoles such as [ Mg Ti ″ ‐ 2 Er Ba ∙ ] , [ Mg Ti ″ ‐ V O ∙ ∙ ] and [ 2 Er Ti ′ ‐ V O ∙ ∙ ] to enhance dielectric relaxation behavior which is considered to be the reason for the improved dielectric temperature stability. When x = 0.4, optimized dielectric ceramics are obtained with ε 25°C = 1820, tanδ = 0.009, resistivity of 1.0 × 10 11 Ω·cm, which meets the EIA X7R standard (−55 °C - 125 °C, TCC ≤ ± 15 %).
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yue Leng,Shengde Dong,Yanxia Sun,Chunxi Hai,Qi Xu,Yuan Zhou
In this study, high-temperature solid-phase techniques are used to prepare pristine and Mg-modified LiNiO 2 cathode materials. Various characterizations are performed to analyze the morphology, structure, and electrical state of the two materials. Electrochemical tests show that Mg doping effectively improves the electrochemical properties of the materials. In particular, the modified sample exhibits a higher specific discharge capacity of 244.5 mA h g −1 than the pristine sample. Moreover, its maximum capacity retention after 304 cycles at 1 C is 54.1%. In situ X-ray powder diffraction imaging reveals that the modified material has better phase-transition reversibility than the pristine material. Density functional theory calculations indicate that Mg-doped Li sites can accelerate Li + transport. Atomic force microscopy results demonstrate that Mg-doped Li sites act as supportive skeletons that enhance the mechanical properties of the material. Therefore, the proposed strategy for the Mg doping of Li sites can improve the architecture of LiNiO 2 cathode materials.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2025
·
IF 4.9
Jiaqi Feng,Wenwen Zhang,Kai Zhang,Hongyu Wang,Changcheng Wu,Jingde Li
NiFe-based materials offer tailorable electronic structure and exhibit promising performance in alkaline hydrogen evolution reaction (HER). Electron-rich earth metals as doping species can regulate the local electronic configuration of NiFe-based catalysts towards improved HER activity. Herein, a low electronegative Mg dopant strategy is utilized to prepare Mg-FeOOH/NiFeO x electrocatalyst for HER. The introduction of Mg improves the bonding strength of Fe-O bond in FeOOH active species, resulting in rapid H 2 O dissociation and improved stability. Meanwhile, Mg-dopant induces a downshift in the d -band center of FeOOH, which weakens the hydrogen adsorption for promoted H 2 production. The Mg-FeOOH/NiFeO x catalyst shows an ultra-low HER overpotential of 18 mV at 10 mA cm -2 and excellent stability in 1.0 M KOH. Moreover, the anion-exchange membrane water electrolyzer reaches 500 mA cm -2 at 1.70 V. This study provides a practical strategy to synthesise high-efficiency NiFe-based HER catalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Yongshun Liang,Haiyang Liu,Ya Li,Lang Xu,Yiyao Li,Yingjiao Yang,Wei Bai,Junming Guo,Mingwu Xiang
LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM) layered oxide is recognized as a promising cathode material of lithium ions battery and generally synthesized using a co-precipitation reaction to firstly obtain hydroxide precursors following by high-temperature solid method. The co-precipitation has the relatively complex and time-consuming process, whilst showing the nonuniform lithium distribution when mixed with spherical hydroxide precursors. Herein, a facile one-step microwave method is proposed to fast synthesize various LiNi 0.5 Co 0.2 Mn 0.3-x Mg x O 2 (x ≤ 0.05) cathode materials at a microwave power of 720 W only for 5 min. And then traditional solid method is used to further enhance the crystallinity and reduce the Li + /Ni 2+ mixing of the LiNi 0.5 Co 0.2 Mn 0.3-x Mg x O 2 samples. The as-prepared LiNi 0.5 Co 0.2 Mn 0.3-x Mg x O 2 samples have analogous polyhedral morphology and uniform element distribution. Also, the substitution of appropriate Mg-doping for Mn element boosts the stable layered structure and facilitates the Li + ions diffusion. Owing to these merits, the optimized LiNi 0.5 Co 0.2 Mn 0.27 Mg 0.03 O 2 cathode material exhibits a higher capacity retention of 87.90 % than that of the pristine LiNi 0.5 Co 0.2 Mn 0.3 O 2 sample (78.12 %) after 100 cycles at 0.2C.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Energy Storage Materials
·
2021
·
IF 17.789
Yuansheng Shi,Zhizhen Zhang,Pengfeng Jiang,Ang Gao,Kangwan Li,Qinghua Zhang,Yang Sun,Xueyi Lu,Dapeng Cao,Xia Lu
Layered sodium transition metal oxides (NaTMO 2 ) have garned considerate attention as candidates for cathode materials in practical Na-ion batteries because of their potentially high energy density and operating voltage. Among the several categories (P2, P3, O3) of layered NaTMO 2 materials, P3 type cathodes are least studied due to the fast capacity/voltage fading induced by P3-O3 phase transition, as shown by the very few compositions visited in previous reports. It is highly desirable to stabilize the P3 phase throughout the sodium extraction/insertion process as P polytype allows facile migration of Na + -ions between two adjacent prismatic sites. In this work, we synthesized a phase pure P3-Na 0.75 Mg 0.08 Co 0.10 Ni 0.2 Mn 0.60 O 2 (P3-MNCM) via the incorporation of Mg, while successfully maintains the P3 structure during the charging/discharging process. This together with good ionic conductivity , endows good structural reversibility, and consequently leads to superior cycling performance and rate performance than undoped composition. In situ X-ray diffraction (XRD) further verifies that P3-MNCM cathode demonstrates a near zero strain feature. Of special importance is that the P3-O3 phase transition is effectively suppressed with the incoporation of Mg into the transition metal layer. These findings demonstrate the potential of P3 structure as a promising choice for Na ion cathode materials, which open a feritile avenue and will hopefully inspire more endeavors in the exploration of high performance sodium ion batteries.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）