CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Xin Wang,Yunfei Gao,Zhiyang Cai,Shan Hu,Junxian Zhang,Fuchen Wang,Yifei Wang
Chemical looping air separation (CLAS) represents a promising approach to use thermal energy for high-purity oxygen production. CeO 2 represents a class of material that uncouples oxygen using thermal energy, but the required temperature is usually very high (>1400 °C). This limits the potential use for CeO 2 -based materials in CLAS. This study reports a Pr doped CeO 2 oxygen sorbents for chemical looping air separation at ultra-low temperatures. The as-formed Ce 1-x Pr x O 2 solid solution can uncouple oxygen effectively, achieving a redox oxygen capacity of 0.88 wt% at isothermal condition as low as 500 °C. The redox oxygen capacity can be further enhanced to 1.63 wt% in temperature-swing cycles between 400 °C and 900 °C. Moreover, oxygen partial pressure-swing cycles show that the Ce 1-x Pr x O 2 solid solution maintains 95% of its redox oxygen capacity at oxygen partial pressure as low as 0.02 atm, indicating its potential applications in oxygen separation from diluted air. DFT calculations and other physio-chemical characterizations indicate that Pr doping can effectively reduce the oxygen vacancy formation energy, and gaseous oxygen is uncoupled when Pr 4+ and Ce 4+ are reduced in the Ce 1-x Pr x O 2 solid solution. Overall, this study highlights the novel performance of CeO 2 with Pr doping and could offer insights into CeO 2 modification strategies for thermal chemical applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Surfaces and Interfaces
·
2024
·
IF 5.7
Fan Wang,Fansheng Zeng,Zhongyang Yu,Chaoyi Chen,Xuelong Huang,Wei Zhang,Yuanpei Lan,Junqi Li
Aimed to evaluate the influence of nitrogen doping on the photocatalytic performance of ceria, three ceria samples, including nitrogen doped, rich oxygen vacancies contained and contrastive ceria were prepared from the decomposition of CeCO 3 OH under varied atmospheres. The physico-chemical characterizations and photocatalytic properties towards methylene blue (MB) and tetracycline (TC) of the obtained ceria were comparatively discussed in detail. Nitrogen-doped CeO 2 exhibited significantly superior photocatalytic activities compared to CeO 2 with rich oxygen vacancies for MB and TC photodegradation, which is mainly attributed to the significantly enhanced separation of photo-generated carriers ( e − / h + ). Density Functional Theory (DFT) simulation suggests that the introduced impurity states of N-doped CeO 2 advance the formation and separation of e − / h + . Moreover, the electrons are simultaneously excited from N 2 p and O 2 p , which further elevates the carrier concentration on the nitrogen-doped CeO 2 , and promotes the effect of e − during the photodegradation. The obtained results offer powerful evidences for the significant enhancement on photocatalytic performances of nitrogen doped CeO 2 .
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
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Jiaojie He,Yuhong Xu,Penghui Shao,Liwei Yang,Yan Sun,Yue Yang,Fuyi Cui,Wei Wang
The electronic structure and associated chemical characteristics of metal-based adsorbent are directly relevant to the selectivity and efficiency of phosphate uptake. However, few studies focus on the nature of metal centers’ electronic orbit (i.e., the coordination number and valence state). Herein, we report a coordinatively unsaturated Ce(III)-based materials, which exhibits excellent potential in effective phosphate removal. Via controlled partial thermolysis and the following reduction process, the valence state and coordination number of original Ce(III)-MOF (denoted as CM) can be tuned and optimized. The manufacture of more coordination vacancy was fulfilled through total release of solvent molecules under annealing at 300 °C in air. Meanwhile, the reduction procedure could precisely tuned the ratio of Ce(III)/Ce(IV). The result shows that samples only annealed induce a sharp decrease of the phosphate capacity due to the high amount of Ce(IV) state. After the reduction process, the XPS spectra reveal the growth of oxygen vacancy content calculated as 11.6% and the increase of Ce(III)/Ce(IV) values from 0.79:1 to 1.36:1. Based on those great improvement of the unsaturated coordination numbers and the recovery of Ce(III) content for metal centers, the maximum capacity of CM-300(R) to adsorb phosphate is up to 273 mg/g, 2.6 times larger than that of pristine CM. Those new insights provide a novel strategy for synthesizing a highly active adsorbent by controlling the electronic structure of metal centers for efficient phosphate removal.
研究领域:
环境科学
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材料科学
✓ 已验证
DOI
高影响因子
Catalysts
·
2022
·Vol. 12
·期 5
·460
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IF 4.501
Yifan Zheng,Lijun Lu,Wei Chen,Anmin Zheng,Aiwen Lei,Abhishek Dutta Chowdhury
Global warming and rising waste content collectively accelerate the development of renewable-derived ‘low-carbon’ chemical technologies. Among all abundant renewables, marine-/food-waste-derived chitin, the only nitrogen-containing sustainable biomass, contains the uniqueN-acetylglucosamine units, which could be synthetically manipulated to a plethora of organonitrogen chemicals. Herein, we report the efficient one-step catalytic valorization of chitin toN-acylethanolamine over cost-effective Ni/CeO2-based materials, which interestingly demonstrate shape-based reactivity based on CeO2supports. In general, all three catalysts (Ni on cubic-, rod-, and polyhedral-shaped CeO2supports) were active for this reaction, but they differed in their catalytic efficiency and time-monitored reaction profiles. Herein, Ni on cubic-shaped CeO2delivered relatively better and stable catalytic performance, along with its rod-shaped counterpart, while the polyhedral CeO2-based material also delivered decent performance. Such interesting catalytic behavior has been corroborated by their physicochemical properties, as revealed by their characterization studies. Herein, to establish an appropriate structure-property-reactivity relationship, multimodal characterization techniques and control mechanistic experiments have been performed. This work demonstrates a concept to reduce the consumption of primary carbon resources and increase the utilization of secondary waste materials to facilitate a smooth transition from a linear economy (cf. cradle-to-grave model) to a circular economy (cf. cradle-to-cradle model).Keywords:chitin;waste valorization;heterogeneous catalysis;ceria;functionalization of C–C bonds
研究领域:
生物化学
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环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Sujie Shan,Tao Zhang,Wei Wang,Dongmei Liu,Wenxin Shi,Fuyi Cui
Recently, to mitigate eutrophication nuisance, the use of cerium(Ce)-based materials for effectively eliminating phosphate from waters and wastewaters has garnered increasing attention. However, insufficient sorption capacities as well as difficulty for spent sorbents separation still restrict their development and utilization. Herein, magnetic Ce 2 (CO 3 ) 3 ·xH 2 O/Fe 3 O 4 (M−HCC) sorbent was firstly synthesized via a facile co-precipitation method and employed for removing phosphate from aqueous solutions. It was showed that M−HCC displays a fast sorption kinetic, notable sorption capacity of 98.3 mg-P/g, wide pH applicable range (pH 3–9) and strong selectivity for phosphate in the co-existence of common anions (i.e. Cl − , NO 3 − , SO 4 2− , HCO 3 − and F − ) and cations (i.e. Ca 2+ and Mg 2+ ). Moreover, the uptake of phosphate by M−HCC was independent of the ionic strength of solution. The application of as-prepared sorbent in eutrophic water and wastewaters evidenced that, M−HCC performs very well in the real water bodies, and the phosphate level of outflow could be reduced from 0.55 mg-P/L to ≤ 0.03 mg-P/L at a low dosage of 0.1 g/L. As the spent M−HCC could be easily recovered from treated liquids and regenerated satisfactorily, M−HCC also exhibits a good reusability. Mechanistic investigation revealed that the formation of inner-sphere complexation via ligand exchange between phosphate and carbonate/surface hydroxyls of M−HCC as well as electrostatic attraction are answerable for the superior uptake of phosphate by M−HCC. Overall, M−HCC sorbent with the novel species of Ce 2 (CO 3 ) 3 ·xH 2 O as active site could be considered as a promising alternative for phosphate removal from waters or wastewaters.
研究领域:
环境科学
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水处理技术
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2022
·
IF 7.139
Zhihua Gao,Fengyan Fu,Zhaozhi Zhang,Lili Niu,Min Jin,Jian Zhang,Zekun Zhao
Support materials are indispensable to promote the durability of iron oxides for chemical looping applications. However, the dilution effect of supports on the active phase would lead to decreased bulk oxygen conduction, thus leading to compromised activity. Here, we propose several Gd 3+ , La 3+ and Nd 3+ doped CeO 2 as active supports for iron oxides and investigate the support effect to improve hydrogen generation via chemical looping water gas shift . The characterizations show that the dopants improve the oxygen vacancy concentration in the CeO 2 lattice and Fe 2 O 3 /Ce 0.8 Gd 0.1 La 0.1 O 2-δ exhibits the most oxygen vacancy concentration among all the oxygen carriers. Pulse reactions of oxygen carriers show that an abundance of oxygen vacancy concentration can promote the lattice oxygen transfer in bulk, thus contributing to improved redox reactions . The high oxygen conductivity mitigates the dilution effect on the active phase. Therefore, Fe 2 O 3 /Ce 0.8 Gd 0.1 La 0.1 O 2-δ shows the highest hydrogen yield (∼9.49 mmol −1 .g −1 ) and hydrogen generation rate (∼0.632 mmol.g −1 .min −1 ) with only a slight decrease at 650 °C over 100 cycles. Overall, this work highlights the influence of support properties on the redox reactivity of iron oxides for chemical looping applications.
研究领域:
材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Weirui Chen,Jinxin Xie,Xukai Li,Laisheng Li
The low efficiency of peroxone (O 3 /H 2 O 2 ) at acidic and neutral pH restrained its application in water purification . To overcome this shortcoming, CeO X @SiO 2 with large surface area, abundant surface oxygen vacancies (V o ), Lewis sites (L sites) and high Ce(III)/Ce(IV) ratio were synthesized to change the traditional electron transfer pathway between O 3 and H 2 O 2 . V o was facile in absorbing H 2 O 2 to form V o -H 2 O 2 and L sites were capable of absorbing O 3 to form L-O 3 . The electron at V o could be donated to V o -H 2 O 2 and generate V o -HO 2 − , which then effectively triggered the decomposition of L-O 3 at CeO X @SiO 2 ’s interface and O 3 in bulk solution. The electron transfer at the solid-liquid interface with the help of Ce 3+ /Ce 4+ redox cycle and V o was pH independent and different from the traditional electron transfer of peroxone reaction. Nitrobenzene (NB) mineralization was promoted to 92.5% in CeO X @SiO 2 -peroxone, but only 63.8% TOC was removed in tradition peroxone process. Moreover, CeO X @SiO 2 -peroxone had a wide pH application range. NB’s degradation in CeO X @SiO 2 -peroxone process followed the co-oxidation mechanism of superoxide free (•O 2 − ) and hydroxyl radical (•OH). The finding of this study could broaden the popularization of peroxone in water treatment and provided a strategy for catalyst design.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
Applied Materials Today
·
2024
·
IF 7.2
Guangyou Shi,Qingshan Liu,Yu Huang,Yonghui Wu,Run Huang,Ling Zou,Xiaoling Liu,Jinbao Li,Jian He,Lu Yang,Xiaochao Yang
Hollowing and doping are two important technologies to improve the performance of nanoparticles. Ideally, doping the hollow nanoparticles can generate synergistic effect of these two technologies. However, this strategy is challenged by low doping content and/or loss of hollow structure. Herein, a method following Ostwald ripening pathway is developed to synthesize hollow ceria nanoparticles. Sixteen ions are selected to dope the nanoparticles with aim to find out how the Ostwald ripening is modulated by these ions. The results demonstrate that the solid nanoparticles formation and the central parts dissolution processes involved in the Ostwald ripening are highly dependent on the negative logarithm solubility product constant ( p K sp ) values of the doping ions. The low p K sp ions can not be easily incorporated into the solid nanoparticles thus their doping contents are low even they do not impair the central parts dissolution of the nanoparticles. In contrast, the high p K sp ions can be readily incorporated into the solid nanoparticles resulting in high doping contents, but these ions can delay the dissolution of the central parts leading to the formation of yolk-shell structures in the nanoparticles. The revealed mechanisms provide very useful information to construct doping platform for screening highly active hollow ceria nanoparticles.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2021
·
IF 6.024
Jingjing Liu,Fan Yang,Zheng Jiang,Yifei Zhang,Enyi Hu,Hao Wang,Xinlei Yang
Low temperature performance and durability have been the main indicators of fuel cells. In this work, we develop a novel solid oxide fuel cell (SOFC) by constructing a heterostructure electrolyte based on Gd0.15Ni0.05Ce0.8O2−δ (GNDC) and SnO2, which acquires an open circuit voltage of 1.026 V and a maximum power density (MPD) of 879.4 mW cm–2 at 550 °C. It is demonstrated that the composites are a hybrid ionic and protonic conductor with competent conductivity of 0.124–0.220 S cm–1 at 450–550 °C. Further characterization authenticates the valence state alteration of Ni, creating more oxygen vacancies during the tests. Also, the existence of the Schottky junction is detected to confirm the electron suppressing effects due to the Schottky barrier. These two key points guarantee the superionic conductivity and promising durability of the cells. This work thus presents a creative insight for constructing low temperature solid oxide fuel cells (LT-SOFCs).
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2020
·
IF 4.551
Junjie Zhou,Hao Liu,Yichao Lin,Chen Zhou,Aisheng Huang
A well-shaped Ce (IV)-based metal organic framework (Ce-BDC) is prepared under solvothermal method. The influence of synthesis time, temperature and the amount of acetic acid (HAc) as a modulator is studied to develop a new strategy for the synthesis of well-shaped Ce-based MOF. The relationship between the synthesis parameters and morphology as well as crystallinity of Ce-BDC is investigated by XRD and SEM. Furthermore, the obtained well-shaped Ce-BDC shows a CO 2 uptake capacity of 2.28 mmol g −1 at 0 °C and 1.0 bar. Meanwhile, the breakthrough curve behaviors of Ce-BDC are investigated for a CO 2 /CH 4 and CO 2 /N 2 mixture gas . It is found that the Ce-based MOF adsorbs CO 2 under ambient temperature and pressure, but completely excludes CH 4 and N 2 , suggesting that it is a promising adsorbent for efficient separation of CO 2 from natural gas.
研究领域:
材料科学
·
无机化学
·
多孔材料
·
气体分离
·
环境催化
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）