JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2019
·
IF 3.218
Meng Zhang,Zhengwei Xiong,Jinzhi Jia,Zhangyang Zhou,Botao Wu,Yuanyuan Ni,Xiuwen Zhou,Linhong Cao
A hollow Cr 2 O 3 /CrN nanoshell was synthesized directly in the ammonia atmosphere. X-ray diffraction analysis indicated that the crystalline phase was gradually transformed from the hexagonal Cr 2 O 3 to cubic CrN, in company with the shrinking of the lattice cells with the increase of ammonification time. Based on its more stable crystalline structure and well conductivity of the CrN relative to the Cr 2 O 3 , the electrochemical performance of Cr 2 O 3 /CrN composites was modified, including increased specific capacitance, enhanced cycle stability and improved electrical conductivity. While the ratio of oxygen to nitrogen is 81.89%, the Cr 2 O 3 /CrN composites own the highest specific capacitance of 333.2 F/g at 10 mV/s and maintain an initial capacitance of 84.7% after 5000 charge-discharge cycles, attributing to the maximum specific surface area. The variation of electrochemical properties of Cr 2 O 3 /CrN composites was systematically studied. These results provided a new route for designing transition metal oxides/transition metal nitrides composites as electrode materials for supercapacitors .
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2023
·
IF 8.2
Peiyuan Xiao,Junqing Xu,Hongliang Shi,Fengyang Du,Huanzheng Du,Guangming Li
The simultaneous reduction of Cr(VI) and sequestration of the resulting Cr(III) in one process is highly desirable as a cost-effective and environmental-friendly approach for the decontamination of Cr(VI)-polluted wastewater. However, most of the existing adsorptive materials are only effective in low pH environments (pH = 1–3), severely restricting the adsorption efficiency and cost effectiveness. Herein, we proposed a chitosan-based magnetic porous microsphere (PPy@PMCS) for simultaneous Cr(VI) reduction and Cr(III) sequestration in a wide pH range. Benefiting from its abundant interaction sites, Cr(VI) was effectively adsorbed on the surface and then immediately reduced to Cr(III) with much lower toxicity. Most importantly, the resulting Cr(III) was in-situ sequestrated by the complexation of chitosan matrix. As a result, PPy@PMCS exhibited a maximum Cr(VI) adsorption capacity of 330.42 mg/g at pH 2.0 and an adsorption capacity of 167.82 mg/g even at near neutral pH (6.0), which is superior to most reported adsorbents. Furthermore, the exhausted PPy@PMCS can be rapidly separated from solutions under an external magnetic field and facilely regenerated. The proposed novel biopolymer-based material shows great application potentials in wastewater treatment.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2025
·
IF 9.5
Meiting Guo,Zhishan Li,Lang Tang,Jingwei Li,Zehua Wang,Bo Wang,Zongping Shao,San Ping Jiang,Zhongwei Yue
Due to their low activation energy and high mobility of proton transfer, protonic ceramic cells (PCCs), including protonic ceramic fuel cells (PCFCs) and protonic ceramic electrolysis cells (PCECs), working at relatively low temperatures (400–700 °C) have gained increasing attention as promising and highly efficient energy conversion and storage technologies to replace the oxide ion-conducting, high-temperature solid oxide cells (SOCs). However, similar to SOCs, Fe–Cr based alloys are also commonly used as metallic interconnects in PCCs. Thus, the practical applicability of Ba-containing proton conducting electrolytes in PCCs is fundamentally related to their tolerance and resistance towards the deposition and poisoning of the volatile chromium species from the Fe–Cr based interconnect. This study focuses on the interaction between the Cr species and the most widely used proton conducting electrolyte BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb1711) within a temperature range from 400 °C to 700 °C. Results indicated that barium oxide and the BZCYYb1711 powder reacted with the Cr2O3 powder at 250 °C and 400 °C, respectively, while the deposition of Cr species on the BZCYYb1711 electrolyte surface occurred at temperatures as low as 500 °C. Ba segregated from the BZCYYb1711 electrolyte and reacted with gaseous Cr species, forming BaCrO4 and causing a significant depreciation in Ba content in the electrolyte. The Cr species also diffused into the inner layer of BZCYYb1711, leading to the segregation of CeO2 and degrading the conductivity of the electrolyte. This study demonstrates that the deposition and poisoning of the Cr species from the Fe–Cr based metallic interconnect are serious issues for the practical and long-term applicability of Ba-containing protonic ceramic materials in PCCs.
研究领域:
材料科学
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能源技术
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Weifang Zhang,Lianyang Huang,LingLing Zhuang,Jiahong Pan,Kun Li,Yu Luo,Chunshan Wu,Menglu Zhang,Chunli Wang
While mechanochemical reactions have garnered attention for their broad applicability and readily attainable operational conditions, their utilization in wastewater purification, particularly for the treatment of chromium-containing effluents, remains limited. In this study, we present a novel mechanism for ball milling-mediated reduction and immobilization of hexavalent chromium, achieving removal efficiencies of up to 93.7% over a pH range of 2.0 to 10.0. This mechanism advocates for the concurrent effect of mechanical force to facilitate the reduction of Cr(VI) to its stable surface form (Cr(III)), and the precipitation of BaCrO 4 , thereby immobilizing the chromium species. Density functional theory calculations demonstrate that oxygen vacancies can efficiently adsorb Cr(VI), thereby imparting electrons to it, consequently facilitating reduction processes. This study provides novel insights into metal ion-contaminated wastewater treatment and the role of naturally generated mechanical forces on the redox processes of chromium species.
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 44
·16890-16897
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IF 4.569
Shaoxi Kong,Mengfei Lu,Shicheng Yan,Zhigang Zou
An effective pathway to cope with the sluggish oxygen evolution reaction (OER) is to accelerate the electron transfer kinetics. Transition metal with high valence states doping can accelerate the reaction kinetics to afford high inherent activity. Herein, a novel trimetallic NiFeCr nanoalloy as an OER electrocatalyst is synthesized by replacing partial Fe in the Ni3Fe alloy with Cr. In the OER process, Cr leached from the surface layer of the NiFeCr alloy to form a core–shell NiFeCr@NiFeOOH structure. The electrons from the OER intermediates were significantly accelerated by the high-valence Cr6+ as an electron acceptor at the core–shell interface. As a result, NiFeCr@NiFeOOH exhibited excellent OER performances with a low overpotential of 209 mV at 25 mA cm−2 in 1.0 M KOH on conductive carbon paper, outperforming the Ni3Fe alloy without Cr doping. Our work provides a new strategy to design and synthesize the NiFe-based alloy with high OER activity.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POWDER TECHNOLOGY
·
2021
·
IF 5.134
Qingqing Hu,Donglai Ma,Yongjie Liu,Qingyun Huang,Zhixiong You,Xuewei Lv
Ferrochromium nitride is an important alloying additive for smelting nitrogen–containing steel. Preparing nitrides by using ammonia gas as reducing and nitriding agent is characterized by high–efficiency and carbon free. In this study, the reaction behavior between chromite spinel and ammonia gas was investigated. Thermodynamic analysis revealed that the reaction was feasible. The transformation of chromite spinel as well as the final products were dependent on reaction temperature, time and input fraction of ammonia gas. The experimental results proved the effect of reaction parameters on the reduction and nitridation process. Chromite spinel was reduced and nitrided to form metallic iron and CrN at temperatures below 950 °C, while metallic iron and Cr 2 N were the main products at 1000 °C. XPS analysis also proved the existence of CrN and Cr 2 N. Ferrochromium nitride with N content treater than 15 wt% was obtained when reducing above 950 °C for 3 h.
研究领域:
材料科学
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冶金工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Storage
·
2024
·
IF 8.9
Shiyang Niu,Shibo Sun,Fujun Chu,Yong Liu,Qinzhi Lai,Yuanhui Cheng
Iron chromium flow battery (ICFB) has the advances of low cost, safety, and independent design of power and capacity, but is restricted by the deactivation of chromium anolytes. Here, a complex of diethylenetriaminepentaacetic acid with chromium ion (CrDTPA) is designed with minimum capacity loss rate and best cycling stability. DTPA is an octadentate ligand and chelates with chromium ions in a seven-coordinated manner. The coordination structure was studied by Nuclear Magnetic Resonance, Fourier transform infrared and UV–vis absorption spectra, and identified as a robust structure. CrDTPA has good electrochemical activity and reversibility with a redox potential of −1.145 V versus saturated calomel electrode. A novel iron chromium flow battery (NICFB) is designed by coupling CrDTPA anolytes and Fe(CN) 6 catholytes. NICFB displays high energy conversion efficiency with coulombic efficiency of 99.0 % and energy efficiency of 82.2 % at 40 mA cm −2 . Importantly, NICFB shows superior cycling stability without performance decay for 160 cycles, ranking the best among recently reported ICFBs. This chelation approach provides a simple and practical method to solve chromium anolytes deactivation and improve cycling stability.
研究领域:
材料科学
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电化学
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能源存储
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2024
·
IF 5.8
Jinlong Wang,Shengqiang Song,Hang Liu,Ao Huang,Yunfei Wang,Mithun Nath
In the study, the solid solubility limits of Cr 3+ in the CaAl 12-x Cr x O 19 phase and leachability of any Cr 6+ safety were investigated. Analytical tools and leaching experiments were used to investigate the Al 3+ substitution in hibonite (CaAl 12 O 19 ) structure by Cr 3+ . The results showed that at Al:Cr=9:3, all the generated phases were chrome-hibonite (Ca 1.06 Cr 2.87 Al 9.07 O 18.99 ) and were also supported by the XPS and Cr 6+ leaching experiments results. However, when proportion of Cr in system increases to Al:Cr=7:5, the primary phases are Ca 1.09 Cr 3.92 Al 8.01 O 18.98 and alumina-chrome solid solution (Al 0.77 Cr 1.22 O 3 ) along with a small amount of wuboraite solid-solution (CaAl 2±x Cr 2±x O 7 , a Cr 3+ phase) and chrome-hauyne (Ca 4 Al 6 CrO 16 , a Cr 6+ phase). At Al:Cr=7:5, distilled water and 0.1 mol/L HCl leach around 1.9 mg/L Cr 6+ , but HCl showed relatively faster leaching of Cr 6+ than water and below the Chinese national standard of waste disposal of 3 mg/L. The maximum solid-solubility limit of Cr 3+ in CaAl 12-x Cr x O 19 could be considered as x =3.9.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
SOLVENT EXTRACTION AND ION EXCHANGE
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2023
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IF 2
Lili Cui,Jungang Cao,Shihui Jiao,Guangsheng Pang,Zhonglin Wei
A selective extraction process for recovering vanadium (IV) over chromium was proposed with use of a mixed extractant consisting of di(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP). The influence of various factors, which included the initial aqueous pH value, the concentration of leach solution and D2EHPA, phase ratio (O/A), extraction equilibrium time and extraction temperature in the extraction process on the separation of V and Cr was investigated. Under the condition of the optimum extraction, vanadium extraction was above 94.0%. Meanwhile, under the optimum stripping conditions, the vanadium stripping was above 93.0% utilizing 1.5 mol/L sulfuric acid as the effective stripping reagent. The regeneration and reusability of the loaded organic phases after stripping were discussed. In addition, continuous three-stage extraction and stripping strategy indicated that the aggregate loss of vanadium was 0.885% and that the purity of vanadium was more than 99.9%. Under the condition of the optimum precipitation, when the pH value of the stripping solution was adjusted to 7.0 with ammonia water, the precipitation efficiency reached 99.93%. The calcination conditions (above 680 °C in air) were finally determined by TG-DTA and TG-MS experiments, and the V2O5 obtained by calcination was characterized by XRD. Additionally, a method for detecting impurity elements in vanadium matrix without interference was established. The recovery technology has practical significance in enlarging production scale, reducing specific energy consumption and cost, and realizing automatic control in vanadium leaching process.
研究领域:
冶金学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Xinqian Li,Bo Li,Shuqi Li,Yaping Dong,Dandan Gao,Zhengrong Niu,Wu Li,Haitao Feng
Removing impurities from hexavalent chromium system without secondary pollution is the key to the successful development of green chromate production technology. Here, hydrated chromium oxide CrO x (OH) 3-2x with lamellar cluster microsphere structure was prepared by in-situ hydrothermal method and used to simultaneously adsorb Si (IV) and V (V) in high concentration Cr (VI) solution. In the in-situ hydrothermal process of pH 7, 160 ℃ for 8 h, the Si (IV) and V (V) removal rates of the actual chromate production Na 2 Cr 2 O 7 -Na 2 SiO 3 -NaVO 3 -H 2 O solution can reach 92.27 % and 94.81 %, respectively, which is higher than the ex-situ removal efficiency of Si (IV) (62.88 %) and V (V) (63.16 %) under the same conditions. Further characterization of STEM-elemental mapping, XPS and FT-IR results indicate that during in-situ adsorption, Si (IV) and V (V) are mainly adsorbed on the surface of CrO x (OH) 3-2X adsorbent by interacting with surface hydroxyl groups. More importantly, the simultaneous formation and adsorption of the adsorbent are more conducive to the full utilization of active adsorption sites on the adsorbent surface. After that, CrO x (OH) 3-2x was converted into nano Cr 2 O 3 with a purity of 97.87 % by simple desorption and calcination processes. In addition, the results of UV–vis DRS and SEM show that the residual Si and V elements in Cr 2 O 3 unexpectedly increase the size of the particles to about 300 nm, which redshifts the absorption band of the blue region by 3.3 nm. This results in more red absorption and makes Cr 2 O 3 more yellowish-green and exhibits excellent pigment properties. Thus, the in-situ synthesis, synergistic adsorption and green conversion of trivalent chromium adsorbent provide a promising and sustainable technology for the purification of high concentration Cr (VI) solution that avoids the discharge of Cr (VI) containing slag.
研究领域:
环境科学
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材料科学
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化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2013
·
IF 1.684
Shengping Wen,Jun Wu,Xiashi Zhu
A simple method for the speciation of chromium(III)/chromium(VI) by flame atomic absorption spectrometry (FAAS) after room temperature ionic liquid (1-octyl-3-methylimidazolium hexafluorophosophate, [C 8 MIM][PF 6 ])-based dispersive liquid–liquid microextraction (DLLME) was developed. Chromium(VI) and total chromium (Cr(VI) and Cr(III)) could be extracted by [C 8 MIM][PF 6 ] at the pH value of 5.0 and 6.5, respectively. The Cr(III) content was calculated by subtracting Cr(VI) from the total chromium. The main factors of DLLME were investigated. Under the optimized conditions, the detection limits (3σ) for Cr(III) and Cr(VI) were 1.00 μg L − 1 and 0.41 μg L − 1 . The relative standard deviations (RSDs) for Cr(III) and Cr(VI) were 3.3% and 4.0% (n = 5, c = 80.00 μg L − 1 ), respectively. The calibration curve exhibited linearity over the concentration range of 5.00–200 μg L − 1 and 3.00–800 μg L − 1 for Cr(III) and Cr(VI). The proposed method was validated by the speciation of Cr(III)/Cr(VI) in certified reference materials for environmental water sample and real samples with satisfactory results.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Analytical Methods
·
2014
·Vol. 6
·期 24
·9777-9782
·
IF 1.938
Shengping Wen,Xiashi Zhu,Xiaoyun Wu,Xingxiu Qin
A novel procedure is presented for the speciation of Cr(III)/Cr(VI) involving directly suspended single droplet microextraction combined with electrothermal atomic absorption spectrometry. In this method, Cr(III) can be extracted with 1-decanol at pH 6.0 due to the formation of a hydrophobic complex, Cr(III)-8-hydroxyquinoline (8-HQ), whereas Cr(VI) remains in the aqueous solution. The Cr(VI) concentration was calculated by subtracting the concentration of Cr(III) from the total chromium concentration after reducing Cr(VI) to Cr(III) by addition of hydroxylamine hydrochloride. Different factors affecting the extraction of Cr(III), such as pH, 8-HQ concentration, stirring rate, extraction temperature and time, and interfering ions, were schematically evaluated. Under the selected conditions, the limit of detection for Cr(III) was 0.03 ng mL−1 with a relative standard deviation of 4.7% (C = 1.0 ng mL−1, n = 5). The calibration curve was highly linear for the Cr(III) concentration range of 0.10–2.0 ng mL−1. The proposed method was validated against certified reference materials of environmental water (GSBZ50027-94, GBW(E)080642), and successfully applied in the speciation of chromium in well and tap water samples.
研究领域:
分析化学
·
环境科学
✓ 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）