JOURNAL OF CATALYSIS
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2022
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IF 8.047
Xilun Zhang,Lin Liu,Jiemin Wang,Xiaohua Ju,Rui Si,Ji Feng,Jianping Guo,Ping Chen
To exploit the ammonia as a carrier for sustainable energy, development of efficient catalysts is highly desired. Oxide supported Ru catalysts have been widely studied in ammonia synthesis for their superior catalytic performances under mild conditions. Here, sub-nanometer Ru clusters on La 2 O 3 (Ru clusters/La 2 O 3 ) catalyst has been synthesized and exhibits superior catalytic performance in ammonia synthesis under mild conditions. Multiple characterizations results reveal that surface La-H species, in situ generated on the surface of catalyst, can significantly boost the activity of Ru clusters/La 2 O 3 catalyst in ammonia synthesis. Detailed mechanistic studies demonstrate that the active La-H species on the La 2 O 3 can not only promote activation and dissociation of nitrogen molecules but also directly involve in ammonia synthesis reaction process via a La-H species-mediated reaction pathway. This work promotes molecular level understanding the active sites and reaction mechanism under real reaction conditions, and will also offer opportunity for guiding the design of efficient Ru-based catalysts for ammonia synthesis.
研究领域:
催化化学
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材料科学
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能源化学
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DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2021
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IF 5.279
Hua Yang,Zhiting Xiong,Zhongrui Xu,Rongxiang Liu
Lanthanum (La), calcium (Ca), and cadmium (Cd) have similar physical and chemical properties because of their similar ionic radius. Although the interactions between La, Ca, and Cd have been frequently reported in plants, few studies have investigated the interactive effects of La and Ca on the growth and Cd accumulation in plants. Therefore, we investigated the interactive effects of La and Ca on the growth and Cd accumulation in wheat under Cd exposure by a hydroponic experiment. The results indicated that wheat growth was significantly affected by La–Cd and La–Ca interactions. The accumulation of Cd in wheat was significantly affected by La–Ca and La–Cd interactions and La–Ca–Cd interplay. Correlation analysis indicated that Ca deficiency stimulated La to promote wheat growth and mitigate Cd toxicity. Simultaneously, a low Ca supply stimulated La to decrease Cd accumulation in wheat and induce TaNramp5 expression. In addition, Cd accumulation in wheat was significantly affected by the W7–La interaction and W7–La–Ca interplay. All of the results suggested that La, Ca, and Cd probably share the same binding sites in calmodulin (TaCaM) and La could affect Cd accumulation in wheat by interacting with TaCaM and then downregulating the expression of TaNramp5.
研究领域:
植物生理学
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环境毒理学
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分子生物学
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农学
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DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2014
·Vol. 2
·期 22
·8557-8570
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IF 0
Lina Chong,Jianxin Zou,Xiaoqin Zeng,Wenjiang Ding
In the present work, two new reversible hydrogen storage composites, NaBH4 + LaF3 and NaBH4 + LaH2, have been prepared through a mechanical milling method with the aim of comparatively studying the effects of La fluoride and La hydride on the hydrogen sorption behaviors of NaBH4. Experimental investigations have shown that both La fluoride and La hydride enable reversible hydrogen sorption in NaBH4. In particular, LaF3 exhibits a superior promoting effect than LaH2, which agrees well with theoretical predictions. Surprisingly, better hydrogen sorption properties can be achieved in both systems through undergoing de-/rehydriding cycles. The reversible hydrogen storage capacity reaches up to 3.0 wt% at 238 °C and 2.9 wt% at 326 °C in NaBH4 + LaF3 and NaBH4 + LaH2 systems after the 6th dehydrogenation, respectively. In both cases, the formation of La boride plays the major role in the reversible hydrogen sorption in NaBH4. The superior promoting effect of La fluoride than La hydride upon modifications of thermodynamics and kinetics of NaBH4 should be ascribed to the following factors: (i) the formation of a thermodynamically more stable compound NaF instead of NaH reduces the overall enthalpy changes of re/de-hydriding reactions in NaBH4 + LaF3 to −31.8 kJ mol−1 H2 and 72.5 kJ mol−1 H2, respectively; (ii) the ion exchange of F− for H− leads to the reduction of the onset dehydrogenation temperature of NaBH4 to 160 °C in the NaBH4 + LaF3 composite; (iii) the F− anion favors the formation of LaB6 while H− favors the formation of LaB4. The role of functional anions and cations, de-/rehydrogenation mechanisms and nucleation modes in the two reversible hydrogen storage composites have been proposed based on experimental and theoretical analyses. The comparison study carried out in this work helps to design and search for new metal borohydride based composites for reversible hydrogen storage.
研究领域:
材料科学
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能源存储
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产品关联
DOI
Journal of Cleaner Production
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2021
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IF 9.297
Liu Xia,Wenjuan Zhang,Jianyong Che,Jun Chen,Peicheng Wen,Baozhong Ma,Chengyan Wang
Phosphate and fluoride are the two most crucial contaminants in water resources. In this work, fluoride and phosphate were separately removed and recovered from wastewater through the step-by-step precipitation method. The thermodynamic analysis proved that the process could be achieved by controlling the pH value and the optimal operating window was predicted by constructing the lg c -pH diagram of the La–F–P–H 2 O system. Lab-scale experiments were performed using La 3+ as a precipitant and the results were well matched with thermodynamic analysis. It indicated that the precipitation of LaF 3(s) was predominated at 1.0< pH < 4.0 with slight precipitation of phosphate, while LaPO 4(s) was primarily formed at a pH range of 5.0–11.0 with fluoride left in the solution. Furtherly, the generated LaF 3 and LaPO 4 were treated with NaOH solution to regenerate the precipitant and recycle fluorine and phosphorus, and the regeneration efficiency reached 97.4% and 74.3%, respectively. Eventually, the continuous experiment for the simulated wastewater revealed that 97.7% of fluoride and 99.9% of phosphate could be removed and recovered by the proposed stepwise precipitation method. The process is eco-friendly and sustainable, not only realizing the removal and recovery of F and P efficiently but also making them separated.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
Journal of Water Process Engineering
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2024
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IF 6.3
Guohan Liu,Na Wei,Wenjun Wu,Qiushan Liu,Yufei Wang,Kemeng Du,Ruiyuan Jia,Yuru Liu,Jin Guo
To control the eutrophication originating from phosphate discharge, a novel adsorptive membrane was prepared by vacuum filtrating lanthanum carbonate modified multi-walled carbon nanotubes (LC@MWCNTs) on the UF membrane. The LC@MWCNTs were firstly made using an in-situ method by adding MWCNTs to LaCl 3 ·7H 2 O solution and forming lanthanum carbonate under alkaline conditions. The adsorption experiments exhibited that the maximum adsorption capacity of LC@MWCNTs was 77.58 mg P/g at pH 5. And the phosphate adsorption by LC@MWCNTs was not predominantly reliant on electrostatic interaction , but rather achieved through chemical interactions. Then, the prepared LC@MWCNTs membrane was systematically evaluated for its phosphate removal efficiency and anti-fouling performance during filtration. With the initial phosphate concentration of 1 mg P/L and membrane flux of 378 L·m −2 h −1 , the phosphate removal by LC@MWCNTs membrane approached almost 100 %. Moreover, the LC@MWCNTs membrane exhibited higher permeability (281.6 L·m −2 h −1 bar −1 ) and effectiveness for humic acid (HA) removal (75 %), and LC@MWCNTs membrane mitigated the fouling caused by HA. XPS , FTIR and XRD elucidated that phosphate removal by LC@MWCNTs membrane primarily through the formation of La-O-P inner-sphere complexes via ligand exchange, resulting in the formation of adsorption product LaPO 4 ·0.5H 2 O. Under strong alkaline conditions, the LC@MWCNTs membrane rapidly restored its phosphate removal performance (30 min) with no significant detachment of the LC@MWCNTs layer, indicating its good recovery and reusability performance. Additionally, the LC@MWCNTs membrane could continuously remove phosphate from actual water, confirming its potential for future practical applications.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Ze Zhu,Xiaoqian Zhang,Ying Peng,Zhenfeng Guo,Yongshuai Xie,Benxue Liu,Guanghui Zhang,Luyi Zhu,Xinqiang Wang,Yonggang Jiang,Jian Feng
Rare earth zirconates have incomparable chemical thermophysical properties , yet the difficulty of preparation methods limit their application as fibrous material. In present work, a spinnable La 2 Zr 2 O 7 precursor, named as carboxylate lanthanum-zirconium (COLZ), was developed using carboxylic acids as structural and functional ligands. When COLZ is in its liquid state, it can be readily processed into desired shapes, allowing preparation of high aspect ratio precursor fibers with dense and bonding-strong internal structures. The spinnability was explained by the transformation from solid to liquid state under external forces, in which dynamic bridging of carboxylate and hydroxyl between nano-sized colloidal particles play a key role. Due to weakly acidic ligands, organics in COLZ can be easily removed, making direct heat treatment at the target temperature possible, which is beneficial for massive production. The strategy of developing spinnable precursor could also be applied to prepare other rare earth zirconate fibers or new multi-oxide fibers.
研究领域:
材料科学
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化学工程
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纳米技术
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热管理
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
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2020
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IF 3.104
Mei Li,Yongcheng Zhang,Haiming Li,Hailing Jiang,Wei Han,Yang Sun
In the present work, cyclic voltammetry (CV), square wave voltammetry (SWV) and chronopotentiometry (CP) were used to investigate the electrochemical coreduction behaviors of La(III) and Mg(II) as well as La(III), Mg(II) and Mn(II) on Mo electrode in LiCl + KCl molten salts. CV and SWV results exhibit that the coreduction mechanism of La (III) and Mg(II) on Mo electrode is that La(III) is reduced and Mg–La intermetallic compound is formed, leading to the deposition potential of La(III) shifting to more positive one. The electrochemical signals pertaining to the formation of metallic La, Mg and Mn as well as Mg–La intermetallic compound are also observed by coreduction of La(III), Mg(II), and Mn(II) in LiCl + KCl molten salt on the inert Mo electrode. However, the electrochemical signals associated with the formation of La–Mn and Mg–Mn alloys are not observed, which means that the depolarization effect of La(III) and Mg(II) does not occur on pre-deposited Mn electrode. The Mg–La–Mn alloys were formed by co-deposition of La(III), Mg(II), and Mn(II) on Mo electrode at various concentration ratios of La(III) and Mg(II). The results of scanning electron microscopy equipped with energy dispersive spectroscopy and X-ray diffraction displays that the Mg–La–Mn alloys are comprised of La–Mg compound Mg 17 La 2 , Mg and Mn phases. The concentration ratio of La(III) and Mn(II) has few effects on the alloy composition .
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
MICROPOROUS AND MESOPOROUS MATERIALS
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2015
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IF 3.453
Shengxue Wang,Wei Li,Song Wang,Jinming Jiang,Zhaohui Chen
Hierarchical porous lanthanum zirconate (La 2 Zr 2 O 7 , LZO) monoliths have attracted numerous attentions as adsorption, catalysis, especially in high-temperature and high water-vapor-containing environments. Herein, La 2 Zr 2 O 7 monoliths with hierarchially distributed pores have been synthesized via a spontaneous route based on a non-alkoxide sol–gel process accompanied by phase separation. Nitrates of Zr(IV) and La(III) were used as precursors, propylene oxide and formamide were used as gelation inducers, and polyethylene glycol was used as phase separation inducer. The mechanisms of Zr(IV)/La(III) binary gelation process and competitive reaction between gelation and phase separation have been discussed. Zr(IV)/La(III) binary gels exist in the form of Zr(IV)-rich gel networks coupled with La(III)-rich discrete entities. The size of the pores can be controlled by adjusting the amount of gelation and separation inducers. The surface area of the as-prepared La 2 Zr 2 O 7 monoliths is 89 m 2 /g. La 2 Zr 2 O 7 monoliths are amorphous and heating in air at more than 600 °C leads to the formation of pyrochlore structure La 2 Zr 2 O 7 . With further increase in temperature, the crystalline degree of LZO monoliths increased. After heat treatment, the macroporous skeleton can be well retained. However, the macropores became slightly smaller and the solid skeleton became fragile. Sintering of the continuous skeleton occurred after heat treatment.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
Minerals
·
2024
·Vol. 14
·期 6
·560
·
IF 2.2
Lijinhong Huang,Xiangrong Zeng,Chunyan Fan,Lihong Liu,Shafiq Alam,Bin Zeng,Shaomin Liu,Wanfu Huang,Ronghua Shu
It is important to recover La3+from metallurgical solutions or wastewater. However, the recovery rate of La3+is usually less than 1% and the recovery methods are not environmentally friendly or user-friendly. Therefore, a straightforward, efficient, clean, and economically friendly method is needed. In this investigation, a modified adsorbent, COSAC-Na2EDTA-15, which was made from theCamellia oleiferashell (COS) and disodium ethylenediaminetetraacetic acid (Na2EDTA), was invented. In addition, characterization of the COSAC-Na2EDTA-15 adsorbent was conducted using SEM and XPS, and the principle of adsorption was revealed. The adsorption kinetics followed P-S-O KM, while the isotherm of COS-activated carbon (COSAC) aligned more closely with the Langmuir model. Compared to COSAC, the maximum La3+adsorption capacity of COSAC-Na2EDTA-15 increased from 50 to 162.43 mg/g, and the content of O and N changed from 7.31% and 1.48% to 12.64% and 4.15%, respectively. The surface of the COSAC-Na2EDTA-15 exhibited abundant C, N, and O elements, and La3+was detected on the sample surface after adsorption. The test and analysis results fully indicate that La3+can be successfully adsorbed on the surface of COSAC-Na2EDTA-15. Because of its easy preparation, low cost, and superior performance, activated carbon made from COS finds extensive applications in the adsorption and recovery of rare earth elements.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2017
·
IF 4.357
Rongshu Zhu,Fei Tian,Sainan Che,Gang Cao,Feng Ouyang
A series of RGO/La-ZnIn 2 S 4 photocatalysts were successfully synthesized using the hydrothermal method with different amount of RGO (0 wt%, 0.1 wt%, 0.5 wt%, 1.0 wt%, 2.0 wt%, 5.0 wt%) and La (0 wt%, 0.1 wt%, 0.5 wt%, 1.0 wt%, 2.0 wt%, 5.0 wt%) and characterized by various analysis techniques, such as XRD , Raman, SEM, UV–Vis, TEM, BET and PL. The photocatalytic H 2 evolution activities have also been evaluated under visible-light irradiation. The H 2 production activity of RGO/La-ZnIn 2 S 4 was influenced by both La and RGO significantly. The activity reached the best when the amounts of La and RGO were both 1.0 wt%. The hydrogen production rate of 1.0Pt/1.0RGO/1.0La-ZnIn 2 S 4 was 2255 μmol g −1 h −1 and the apparent quantum yield and the energy conversion efficiency were 29.45% and 18.79% at 420 nm respectively. The activity was related to the BET surface area, the pore microstructure and the synergistic effect of RGO and La. On the basis of the characterization of the catalysts, the synergistic effect of RGO and La on the photocatalytic activity of RGO/La-ZnIn 2 S 4 was discussed in detail.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yucheng Liu,Qian Xu,Fuping Li,Fan Yu,Zijian Yu,Kaibo Hu,Hao Chen,Xuewei Li,Chonggang Wang,Dong Han Seo,Ming Xie,Sotto Arcadio,Jiuyang Lin,Youming Yang,Yinhua Wan
Rare earth elements (REEs) are commonly categorized into light (LREEs), medium (MREEs), and heavy (HREEs) groups. Separation between LREEs and MREEs or MREEs is relatively straightforward. However, isolating LREEs themselves is particularly challenging because of their similar ionic radii and identical charges. Traditional separation processes are hindered by drawbacks including low recovery rates for dilute REEs, poor selectivity, complex protocols, and environmental pollution. Consequently, developing a cleaner and more efficient method for LREEs separation is imperative. In this study, we employed a single-module hollow fiber supported liquid membrane (HFSLM) system with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) as an extractant to concurrently extract and strip La 3+ and Nd 3+ from the mixed LREEs containing solutions. We also investigated the impact of flow rate, stripping solution acidity, feed solution pH, P507 concentration, Nd 3+ concentration of feed solution, and the volume ratio between the feed and stripping solutions influence the extraction and stripping of LREEs, as well as the molar fractions of La 3+ and Nd 3+ in the solutions. Under optimal condition, the molar fraction of La 3+ was 99.0% in the feed solution, whereas the molar fraction of Nd 3+ reached 91.6% in the stripping solution. Furthermore, the experimental results demonstrated a consistent preference of P507-HFSLM system for extracting Nd 3+ over La 3+ , and the underlying mechanism was thoroughly investigated. In summary, this study offers comprehensive insights and technical approaches for selective separation and purification of LREEs.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Gang Qu,Jingkai Zhou,Dandan Huang
The phase relationships of the ternary system Eu 2 O 3 - La 2 O 3 - ZrO 2 and binary Eu 2 O 3 - La 2 O 3 subsystem were experimentally and thermodynamically studied. Six three-phase fields and nine two-phase ones in the Eu 2 O 3 - La 2 O 3 - ZrO 2 system were investigated by X-ray diffraction, scanning electron microscopy and electron probe microanalysis with wavelength dispersive spectrometer at 1873 K and 1673 K. Nevertheless, there only existed a two-phase region in the Eu 2 O 3 - La 2 O 3 system in the temperature range from 1873 K to 1673 K. After that, the ternary mixing parameters for the system Eu 2 O 3 - La 2 O 3 - ZrO 2 including the binary interaction parameters in the Eu 2 O 3 - La 2 O 3 subsystem are optimized with the CALPHAD (CALculation of PHAse Diagrams) method, based on obtained experimental results. The high-temperature phase relationships and the special type of continuous solid solutions (La 2-x Eu x Zr 2 O 7 ) investigated in present work will contribute to exploring new materials with specific properties such as optical transparency.
研究领域:
材料科学
·
热力学
✓ 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）