JOURNAL OF CHEMICAL THERMODYNAMICS
·
2019
·
IF 2.29
Zhan-Ping Qiao,Meng-Yao Su,Yuan-Lin Dang,Qi-Chao Yang
The phase diagrams of the Mg(NO 3 ) 2 –Ln(NO 3 ) 3 (Ln = Nd, Sm, Eu, Tb)–HNO 3 –H 2 O systems in the (∼20%) HNO 3 regions at T = 298.15 K were determined by using an isothermal solution saturation method. The Schreinemaker’s wet residues method was used to determine the compositions of solid-phases. Both Mg(NO 3 ) 2 –Nd(NO 3 ) 3 –HNO 3 –H 2 O and Mg(NO 3 ) 2 –Sm(NO 3 ) 3 –HNO 3 –H 2 O systems are complicated with three equilibrium solid phases Mg(NO 3 ) 2 ·6H 2 O, Mg 3 Ln 2 (NO 3 ) 12 ·24H 2 O and Ln(NO 3 ) 3 ·6H 2 O (Ln = Nd, Sm). But the systems Mg(NO 3 ) 2 –Eu(NO 3 ) 3 –HNO 3 –H 2 O and Mg(NO 3 ) 2 –Tb(NO 3 ) 3 Tb–HNO 3 –H 2 O are simple eutonic type. The two new solid-phase compounds Mg 3 Nd 2 (NO 3 ) 12 ·24H 2 O and Mg 3 Sm 2 (NO 3 ) 12 ·24H 2 O are congruently soluble in an average medium of ∼20 mass % HNO 3 , and they were identified and characterized by the methods of powder X-ray diffraction, X–ray diffraction single crystal structure analysis, and thermogravimetric/differential thermogravimetric. The XRD diffraction patterns for the two new solid-phase compounds are identical due to their isomorphic structure. They belong to hexagonal systems, with space group R 3 . For Mg 3 Nd 2 (NO 3 ) 12 ·24H 2 O, a = b = (1.0993 ± 0.0005) nm, c = (1.7211 ± 0.0007) nm, V = (1.8012 ± 0.0013) nm 3 , D c = (4.2532 ± 0.0024) g·cm −3 , Z = 3; for Mg 3 Sm 2 (NO 3 ) 12 ·24H 2 O, ( a = b = 1.1198 ± 0.0004) nm, c = (1.7257 ± 0.0006) nm, V = (1.8742 ± 0.0011) nm 3 , D c = (4.1201 ± 0.0012) g cm −3 , Z = 3. The standard molar enthalpies of solution of the compounds Mg 3 Nd 2 (NO 3 ) 12 ·24H 2 O and Mg 3 Sm 2 (NO 3 ) 12 ·24H 2 O in water (aq) were measured to be (101.26 ± 0.77) kJ mol −1 and (80.27 ± 0.81) kJ mol −1 , and their standard molar enthalpies of formation were calculated to be – (12214.13 ± 2.5) kJ mol −1 and – (12183.6 ± 2.5) kJ mol −1 , respectively.
研究领域:
化学
·
物理化学
·
材料科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2016
·
IF 3.205
Jiaguang Zheng,Xuezhang Xiao,Liuting Zhang,Yan He,Shouquan Li,Hongwei Ge,Lixin Chen
Mg(BH 4 ) 2 has been considered as one of the promising light metal complex hydrides due to its high hydrogen capacity and low cost. But its higher thermal stability (dehydrogenation at above 300 °C) needs to be improved for the practical application. In this study, the aluminum hydride AlH 3 was introduced into complex borohydride Mg(BH 4 ) 2 to synthesize a new Mg(BH 4 ) 2 AlH 3 composite by ball milling method. It is found that the active Al ∗ formed from the self-decomposition of AlH 3 can effectively improve the dehydrogenation properties of Mg(BH 4 ) 2 , the Mg(BH 4 ) 2 AlH 3 composite starts to release hydrogen at 130.8 °C with a total hydrogen capacity of 11.9 wt.%. The dehydrogenated products of the composite is composed of Mg 2 Al 3 and B at 350 °C, resulting in the improved hydrogen desorption properties of Mg(BH 4 ) 2 AlH 3 composite. The Mg 2 Al 3 and B products would be further transformed into MgAlB 4 and Al at 500 °C. Moreover, the Mg 2 Al 3 and B dehydrogenated products show better reversible hydrogen storage property than that of the MgAlB 4 and Al products. This research shows a way to alter hydrogen de/hydrogenation route and reversibility of Mg(BH 4 ) 2 complex hydride by compositing with AlH 3 and controlling the dehydrogenation temperature.
研究领域:
材料科学
·
能源化学
✓ 已验证
DOI
高影响因子
CRYSTAL GROWTH & DESIGN
·
2014
·
IF 4.558
Huachao Ding,Haihua Pan,Xurong Xu,Ruikang Tang
Magnesium ions (Mg2+) are widely present in biological fluids, and they are suggested as the vital factors that inhibit spontaneous hydroxyapatite (HAP) precipitation in nature. However, the regulation mechanisms of Mg2+ on HAP crystallization are still under intensive debates. We find that a typical precipitation of HAP from supersaturated solutions should include five stages: s1, formation of ion clusters and amorphous calcium phosphate (ACP); s2, stabilization of ACP; s3, transformation from ACP to HAP via dissolution and crystallization; s4, classical crystal growth of HAP; s5, HAP aging under a near equilibrium state. Actually, Mg2+ ions exhibit different inhibitory effects on these stages. The ions have a negligible influence on the kinetics of initial ACP formation in solutions (s1) and final aging of crystals (s5). Rather, the ions can either adsorb onto or incorporate into the ACP precursor particles during s1. In s2, the lifetime of ACP in solution is extended significantly by both two types of Mg2+ ions. However, the absorbed ones are more effective than the incorporated ones on the inhibition of the phase transformation from ACP to HAP in this s2. In stages of s3 and s4, it is only surface Mg2+ ions that retard crystal growth of HAP and the incorporated Mg2+ become inert. These detailed findings reveal how Mg2+ ions affect the crystallization process of HAP mineralization from supersaturation. Such a detailed understanding can provide a chemical strategy for precise regulation of HAP formation kinetics in intermediate phase mediated crystallization.
研究领域:
生物材料学
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矿物学
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生物化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2021
·Vol. 11
·期 8
·4365-4372
·
IF 3.361
Wei Wang,Xiao-Na Yang,Yang Wang,Yong Fan,Jia-Ning Xu
The design of a highly adhesive, defect-free and low-temperature sol–gel coating for the protection of magnesium alloys is desirable yet challenging. In this study, a novel SiO2-based sol–gel coating is developed by a ring-opening addition reaction. Notably, the integration of individual sol clusters endows the sol–gel coating with a smooth and compact surface morphology, and eliminates the potential corrosion site of the low-temperature-prepared sol–gel coating. Besides, the as-obtained sol–gel coating exhibits excellent metallic adhesion nature. Most importantly, it increases the overall impedance modulus by 27 times than that of the conventional strategy and decreases the corrosion rate from 3.8 ± 0.5 mg cm−2 per day (commercial chromate conversion coating) to 0.5 ± 0.2 mg cm−2 per day.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
Membranes
·
2022
·Vol. 12
·期 9
·839
·
IF 4.562
Xianjie Zeng,Li Xu,Tao Deng,Chengyi Zhang,Wei Xu,Wen Zhang
The separation of lithium and magnesium from salt-lake brines with high Mg2+/Li+ratios is a main challenge for lithium extraction. In this work, novel polymer inclusion membranes (PIMs) were developed by incorporating 2-ethylhexyl phosphonic acid mono 2-ethylhexyl (P507) and tributyl phosphate (TBP) as the carriers into cellulose triacetate (CTA) polymers. The Li+could be stripped from the P507-TBP extracting carriers using pure water eluents without adding concentrated hydrochloric acid, which can help decrease carriers’ leakage risk from membrane matrixes and keep the stability of PIMs. The morphology, composition, and wettability of P507-TBP-based PIMs were characterized systematically, and the carrier content in the PIM was also optimized. In the transport experiment with the feed of 0.1 mol/L LiCl and 4.0 mol/L MgCl2, the CTA/P507-TBP60% membrane exhibits a Li+permeability of 4.76 × 10−3mol·m−2·h−1and a Li/Mg separation ratio of 10.2. After recycling seven times, the selectivity of the PIM is well-retained (>10), and the permeability of Li+decreases slightly (less than 15%). With a decent selectivity and excellent stability, PIMs containing P507-TBP carriers show great potential for sustainable and efficient lithium recovery from brines with high Mg/Li ratios.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2020
·Vol. 49
·期 19
·6418-6424
·
IF 4.174
Zhiqiang Guo,Tengfei Pang,Yakong Wang,Yongbin Zhang,Xuehong Wei
Five new heterobimetallic magnesiates bearing bidentate dianionic pyrrolyl ligands have been synthesized through co-complexation with alkali-metal reagents and di-n-butylmagnesium. Single-crystal X-ray structural analysis of these complexes revealed a variety of intriguing bonding modes. These alkali-metal (Li, Na, and K) organomagnesiates were utilized as catalysts for cross-coupling Tishchenko reactions with two different aldehydes. The sodium alkyl magnesiate complex {nBuMg[2-(Me3CNCH2)C4H3N]Na(Et2O)}∞ (3) was identified as a competent catalyst, as it exhibited higher catalytic activities and chemoselectivity under mild conditions.
研究领域:
有机化学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2023
·
IF 10.9
Lina Wang,Peiyi Yan,Huairui Chen,Zhuo Li,Shu Jin,Xiaoxiang Xu,Jun Qian
Narrow bandgap semiconductor MgIn 2 S 4 has been readily grown onto In 2 O 3 nanofibers by an in situ growing method. The so-formed MgIn 2 S 4 -In 2 O 3 hybrid nanofibers are characterized by strong visible light absorption and intimate MgIn 2 S 4 /In 2 O 3 heterointerfaces. Under visible light illumination ( λ ≥ 400 nm), the hybrid nanofibers demonstrate an exceptionally high photocatalytic activity for Escherichia coli ( E. coli ) disinfection, outcompeting pristine MgIn 2 S 4 , naked In 2 O 3 nanofibers, and many other photocatalytic systems reported. Specifically, the hybrid nanofibers achieve a 7 log reduction in viable cells for merely 20 min illumination while pristine MgIn 2 S 4 and naked In 2 O 3 nanofibers alone are almost inactive. Further analysis indicates that the hybrid nanofibers essentially form a type-II semiconductor heterojunctions which enable spatial separation of photocarriers. Owing to the intimate heterointerfaces, photocarriers can be promptly separated and accumulated respectively in In 2 O 3 and MgIn 2 S 4 thereby allowing continuous generation of copious reactive species for disinfection. This work signifies the usefulness of heterointerfaces in promoting photocarrier separation and provides a useful strategy to upgrade photocatalytic performance from otherwise almost inactive semiconductors.
研究领域:
材料科学
·
光催化
·
纳米材料
·
环境科学
·
微生物学
✓ 已验证
DOI
高影响因子
Inorganics
·
2024
·Vol. 12
·期 11
·273
·
IF 3.1
Quan Yang,Xiansong Jia,Zhikang Qin,Xiaoli Ding,Yongtao Li
Carbon-based materials with excellent catalytic activity provide new ideas for the development of magnesium-based hydrogen storage. C-H bonding interactions may play a key role in performance improvement. In this work, we comprehensively compare the magnesium-carbon cloth composites (CC) prepared by method of dry ball milling and wet impregnation. The results were that the hydrogen release activation energy (Ea) of MgH2@CC composites prepared by wet immersion method was 175.1 ± 19.5 kJ·mol−1, which was lower than that of pure MgH2(Ea= 213.9 ± 6.4 kJ·mol−1), and the activation energy of MgH2-CC composites prepared by ball milling method was 137.3 ± 8.7 kJ·mol−1, which provided better results. The kinetic enhancement should be attributed to C-H interactions. The presence of carbon carriers and electron transfer to reduce the activation energy of Mg-H bond fracture. These results will provide further insights into the promotion of hydrogen ab-/desorption from metal hydrides.
研究领域:
材料科学
·
能源化学
·
纳米技术
·
物理化学
·
氢能技术
✓ 已验证
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Mengran Li,Qinke Tang,Lili Yang,Rui Shi,Shihao Chen,Yingzhen Zhu,Yunfeng Zhu,Yao Zhang,Jiguang Zhang,Yana Liu,Jun Wang,Zhixin Ba
Magnesium-based hydrogen storage alloy serves as an ideal substance for hydrogen storage and transportation because of its high hydrogen storage capacity, low expense, and eco-friendly properties. However, the stable thermodynamic properties and poor kinetic properties during de/hydrogenation limit its application. In this work, a novel high-efficiency catalyst CeF 3 was successfully synthesized and induced into Mg 90 Al 10 , which exhibited excellent performance during de/hydrogenation. In particular, the Mg 90 Al 10 + 8 wt% CeF 3 can absorb 4.0 wt% hydrogen within 600 s at 200 °C, and release 4.3 wt% hydrogen within 900 s at 275 °C, better than the Mg 90 Al 10 that can only absorb 1.36 wt% and release 0.3 wt% hydrogen in similar conditions. Meanwhile, the introduction of CeF 3 can also decrease the dehydrogenation apparent activation energy (E a ) of Mg 90 Al 10 obviously from 155.95 kJ/mol to 79.31 kJ/mol. The Al 4 Ce and MgF 2 formed in situ, combined with the high thermal conductivity of Al in charge of the good hydrogen storage behavior of Mg 90 Al 10 + 8 wt% CeF 3 . The study results are of great importance for applying Mg-Al hydrides in solid-state hydrogen storage.
研究领域:
储能
·
材料科学
·
催化
·
氢能
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Chenjie Dong,Guansheng Li,Jiajing Zhu,Jie Cui,Liangjun Huang,Hui Wang
MgH 2 is a high-density hydrogen storage material but requires an efficient catalyst to improve its poor kinetics and reduce high operating temperature. TiO 2 is a widely used photocatalyst for water splitting and hydrogen production, and has also demonstrated catalytic ability in the gas-solid reaction of MgH 2 . In this study, we synthesize the Ni-doped TiO 2 nanoparticles, which significantly reduce the hydrogen absorption temperature down to subzero temperatures. The milled composite of MgH 2 with 10 wt% Ti(5Ni)O 2 can absorb 5.25 wt% H 2 within 30 s at 25 °C, 4.30 wt% H 2 within 50 s at 0 °C, and 3.94 wt% H 2 within 50 s even at a low temperature of −30 °C. This composite can release 6.04 wt% of hydrogen in 3 min at 250 °C, and the dehydrogenation activation energy is reduced to 74.57±1.36 kJ/mol, a notable reduction in comparison to that observed in pure MgH 2 . This study demonstrates the potential of the modified TiO 2 as an important kind of catalyst for solid-state hydrogen storage materials.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
CORROSION SCIENCE
·
2017
·
IF 5.245
Chunmin Wang,Jun Shen,Fuxing Xie,Bin Duan,Xiong Xie
Dopamine (DA), with strong adhesion to metal substrate via self-polymerization reaction, was introduced as a versatile template layer for subsequent polyether imide (PEI) deposition to confer a highly robust coating on AZ31 magnesium alloy . The complicated corrosion behaviour of the coating was disclosed and investigated by employing electrochemical impedance spectroscopy (EIS) coupled with equivalent electrical circuits (EECs) analysis. The results showed that the hybrid PEI/PDA coating exhibited evidently higher retardation performance (up to 35 days) after immersing in 3.5 wt.% NaCl solution compared to PDA or PEI coated Mg.
研究领域:
材料科学
·
腐蚀与防护
✓ 已验证
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
危险品化学品经营许可证（带存储）