CATALYSIS LETTERS
·
2021
·Vol. 151
·期 8
·2250-2256
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IF 3.186
Liu Qi,Wang Shihao,Xu Gang,Wu Minghong,Chen Jianjun,Li Junhua
Abstract A novel TiO 2 -supported vanadium-substituted tungstophosphoric acid (PW 11 V/TiO 2 ) catalyst was designed and applied for selective catalytic reduction of NO x by NH 3 . Compared with the commercial tungstophosphoric acid (PW 12 /TiO 2 ), PW 11 V/TiO 2 displayed a nearly 90% activity improvement at 300 °C. In addition, the favorable resistance and stability to SO 2 were also obtained over PW 11 V/TiO 2 catalyst. Phase analysis and spectroscopy results indicated the vanadium was successfully incorporated into the molecular structure of PW 12 , and the Keggin framework still keep stable over the TiO 2 support. H 2 -TPR test proved the incorporation of vanadium promoted the redox ability of PW 11 V. The present study provides us an effective way to improve the performance of catalytic removal of NO x through tungstophosphoric acid catalyst. Graphic Abstract
After introduction of V species, the obtained PW 11 V/TiO 2 catalyst show better NH 3 -SCR performance and N 2 selectivity than PW 12 /TiO 2 catalyst.
研究领域:
环境科学
·
催化化学
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Yulei Sui,Yueying Hao,Xiaoping Zhang,Jiangpeng Li,Gongyu Wen,Shengkui Zhong,Ziwei Zhang,Ling Wu
Layered transition metal oxide Na 0·67 Fe 0·5 Mn 0·5 O 2 is considered as a promising cathode material of sodium-ion batteries because of its naturally elemental abundance and high energy density . However, low rate capability and poor structural reversibility of Na 0·67 Fe 0·5 Mn 0·5 O 2 greatly hinder its large scale application. In this study, V-substituted Na 0·67 Fe 0·5 Mn 0·5 O 2 cathode material with improved electrochemical performance is successfully synthesized via a sol-gel method. The effects of V-substitution on chemical composition, crystal structure and morphology of Na 0·67 Fe 0·5 Mn 0·5 O 2 are studied in detail. Furthermore, modification mechanisms on the improved electrochemical performance by V-substitution are investigated. The results demonstrate that the rate capability and cycle stability of Na 0·67 Fe 0·5 Mn 0·5 O 2 cathode material is significantly elevated by V-substitution. And the enhanced electrochemical properties are mainly attributed to the improved Na + diffusion rate and structural reversibility. This study suggests that introducing V ions into the lattice of Na 0·67 Fe 0·5 Mn 0·5 O 2 crystals is a favorable strategy to improve its electrochemical properties.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ACS Applied Energy Materials
·
2024
·
IF 5.4
Shuaishuai Chen,Hua Li,Yihan Tang,Jingkun Yan,Zhaoxin Lu,Yi Wan,Chun Jiang,Xiaoyi Wang,Xiong Zhao,Zhenlian Chen,Jiliang Wu,Deyu Wang
Bulky substitutions with transition-metal elements are widely used to improve the comprehensive performance of ternary oxide cathodes. As the Ni content increases to 90% and higher, the modification strategies should be reconsidered since the regular remedies have difficulty addressing their inherent drawbacks. Here, we propose the influence of vanadium substitution, which is rarely used in bulky substitution. This modification obviously improves the durability of LiNi0.90Co0.05Mn0.05O2 at high rate and slightly lowers its reversible capacity. As the best sample, the 2% V-substituted sample delivers 174.4 mA h/g in the first cycle and still maintains 72.5% in the 200th cycle under 5 C, respectively. This variation should be dependent on the abated Δc during operation and the enhanced Li+ diffusion coefficient. Furthermore, the ameliorated mechanical behavior is further proved by the intact particles of the 2% V-substituted sample after 200 cycles. Our results demonstrate that vanadium substitution should be one of the potential strategies to modify Ni-rich materials due to their complementarity.
研究领域:
材料科学
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电化学
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Wei Xiang,Lijun Jia,Tingqing Cai,Xuening Han,Mingchao Yang,Huaiwu Zhang
To meet high-power microwave system demands, low-temperature sintered Bi-Li-V substituted YIG ferrites were prepared. The experimental results reveal that Bi 3+ , Li + , and V 5+ occupy the c, a, and d sites of the garnet structure, respectively; the full-site distortion reduces the lattice activation energy, significantly reducing the transformation temperature from perovskite to garnet phase. Additionally, a dual structure with a high percentage of fine grains is observed in the substituted samples, which is an important reason for the large increase in spin-wave linewidth. Isothermal thermodynamic analysis indicates that a sintering mechanism dominated by liquid-phase sintering is conducive to the densification of YIG ferrites. Ferromagnetic resonance linewidth decomposition confirms that, due to the simultaneous increase in the saturation magnetization and the magneto-crystalline anisotropy constant, anisotropy-induced linewidth remains almost unchanged; the dense dual structure leads to a significant reduction in porosity-induced linewidth; ultimately, the ferromagnetic resonance linewidth is greatly reduced.
研究领域:
材料科学
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电子工程
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产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 14
·6636-6645
·
IF 3.925
Huiting He,Min Zheng,Qiang Liu,Jian Liu,Juan Zhao,Yuting Zhuang,Xianxiang Liu,Qiong Xu,Steven R. Kirk,Dulin Yin
Through the amidation reaction with 2-methylimidazole, organic basic groups were introduced into the carboxyl sites of activated carbon to obtain imidazolyl activated carbon. H3+xPW12−xVxO40 (x = 0, 1, 2, or 3) was chemically bonded to the surface, which was used to catalyze the oxidation of perillyl alcohol by hydrogen peroxide. After reaction at 60 °C for 5 h, AC-COIMIH+[H4PW10V2]− could catalyze almost complete oxidation of the substrate, where the conversion reached 97.4%, the selectivity for the 1,2-epoxide was 80.0%, and the stereo configuration of the epoxide product was RR/SS = 5 : 3. In addition, the catalyst could be easily recovered via centrifugation and reused five times without any significant deactivation. By calculating the Fukui function of perillyl alcohol, we consider a proper explanation for the main product from the oxidation of the allyl alcohol. A cooperative epoxidation mechanism with electrostatic adsorption of a double bond, and hydrogen-bonded adsorption of hydroxyl was proposed.
研究领域:
催化化学
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有机合成
✓ 已验证
产品关联
DOI
高影响因子
ChemSusChem
·
2020
·Vol. 13
·期 22
·6016-6027
·
IF 7.962
Zhensheng Shen,Feiping Long,Tian Ma,Huan Li,An Li,Qian Feng,Jiuyi Liu,Yingqiang Sun
Graphical Minimize to enhance : Heteropolyacids enhance bio-oil yield by catalyzing the hydrolysis of cellular compounds and reducing their nitrogen content. This is done by avoiding Maillard reactions between the intermediates during the hydrolysis of carbohydrates and proteins. Hydrothermal liquefaction (HTL) of microalgae for biofuel production is suffering from low bio-oil yield and high heteroatomic compositions owing to their low efficiency and selectivity to hydrolysis of cellular compounds. Hereby we report Keggin-type (Mo−V−P) heteropolyacids (HPAs)-catalyzed HTL of microalgae for efficient low-nitrogen biocrude production. The increases of reaction temperature, reaction time, and vanadium substitution degrees of HPAs are favorable to biocrude yield initially, whereas a significant decrease of biocrude yield is observed owing to the enhanced oxidation of carbohydrates above the optimum reaction conditions. The maximum biocrude yield of HPAs-catalyzed HTL of microalgae is 29.95 % at reaction temperature of 300 °C, reaction time of 2 h, and 5 wt% of HPA-4, which is about 19.66 % higher than that of control with 71.17 % less N-containing compounds, including 1,3-propanediamine, 1-pentanamine, and 2, 2’-heptamethylene-di-2-imidazoline than that of control. This work reveals that HPAs with Brønsted acidity and reversible redox properties are capable of both enhancing biocrude production via catalyzing the hydrolysis of cellular compounds and reducing their nitrogen content through avoiding the Maillard reactions between the intermediates of hydrolysis of carbohydrates and proteins. HPAs-catalyzed HTL is an efficient strategy to produce low N-containing biofuels, possibly paving the way of their direct use in modern motors.
研究领域:
化学工程
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环境科学
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可再生能源
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产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 91
·50277-50284
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IF 3.708
Zonghai Shi,Yunshan Zhou,Lijuan Zhang,Cuncun Mu,Haizhou Ren,Daf ul Hassan,Di Yang,Hafiz Muhammad Asif
Three new supramolecular compounds [H2TPP]1.5[SW11VO40]·5CH3CN·4H2O 1, [H2TPP]2[SW10V2O40]·4CH3CN·3H2O 2, and [H2TPP][SW12O40]·4H2O 3 composed of [H2TPP]2+ cation and vanadium substituted Keggin-type polyoxometalate (POM) anion [SW12−nVnO40](2+n)− (n = 0–2) were prepared and characterized. The third-order nonlinear optical (NLO) and optical limiting (OL) properties of resulting hybrids were studied by using an Nd:YAG laser at 532 nm with a pulse duration of τ = 7 ns. The results demonstrate that all of these supramolecular compounds have significant nonlinear reverse saturated absorption, self-defocusing behavior, and good OL performance, especially for compound 1, which has a second hyperpolarizability γ value of 7.05 × 10−29 (esu) and exhibits a comparable OL performance with the most well-known OL materials such as In(Pc*)Cl indicating that they are potentially excellent NLO materials. Remarkably, it was also observed that the degree of vanadium substitution in POM anions corresponding to different onset of reduction potential influences the NLO and OL properties of the resulting compounds: third-order NLO and OL properties of compound 2 are inferior to those of compound 1, and are better than those of compound 3. Both their second hyperpolarizability γ values and the OL performance were observed to be inversely proportional to the HOMO–LUMO gaps of the resulting compounds. The excited charge transfer from porphyrin to POM anions in the supramolecular compounds when exposed to laser irradiation is thought to play key role in the enhancement of NLO and OL response.
研究领域:
材料科学
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光学
·
化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Jie Li,Huayin Li,Zongyang Liu,Mohcin Akri,Yuan Tan,Leilei Kang,Jun Chi,Botao Qiao,Yunjie Ding
Synthesis of methyl methacrylate (MMA) via direct oxidative esterification from methacrolein (MAL) and methanol (MeOH) is of great significance in chemical industry. Supported gold catalysts are considered as one of the most potential candidates for this reaction but suffer from low activity and deactivation issue. Herein, by modulating the phase structure of hydroxyapatite (HAP) with different cations and anions, a synergic effect between gold and vanadate substituted hydroxyapatite (HVP) support for the synthesis of MMA was discovered. In direct oxidative esterification, among the evaluated catalyst/support systems, Au/HVP catalyst displays the best performance and unprecedented stability, which acts as one of the best-performing gold catalysts for oxidative esterification. Various characterizations such as X-ray diffraction (XRD), Raman spectra, scanning electron microscopy (SEM), transmission electron microscope (TEM) and in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of CO were conducted to disclose the structural and electronic property of the catalysts. Through in-situ FT-IR spectra of MAL and MeOH, the substrate was proved to be easily transformed on Au/HVP catalyst to ester. Besides, the presence of O 2 was found to facilitate the adsorption of MAL. The results of temperature programmed desorption (TPD) of O 2 implied that gold particles together with HVP support is promotional for activation and dissociation of oxygen, leading to good activity and high selectivity.
研究领域:
催化
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材料科学
·
化学工程
✓ 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）