JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Cheng Liu,Huiling Chen,Qi Chen,Jinhong Bi,Jimmy C. Yu,Ling Wu
A series of Al 3+ -doped UiO-66(Ce) MOFs (U(Ce x Al 1−x )) was developed to reveal the roles of metal doping on active site formation and substrate activation in photocatalytic selective transformation of amines to imines. Al 3+ doping induced crystal structure distortion to form coordinately unsaturated metal (Al, Ce) sites as Lewis acid sites to chemisorb and activate benzylamine (BA). In situ FTIR revealed that the Al site with stronger acid strength facilitated BA activation. The activation degree of N–H bonds in BA was evaluated by changes of calculated force constant. The intermediate products were confirmed through time-dependent in situ FTIR. The Al 3+ -doped sample U(Ce 0.90 Al 0.10 ), the optimal catalyst, showed a significantly increased BA conversion (97.6 %) than that (47.5 %) of undoped sample, which was attributed to enough active sites and the optimal charge mobility. Finally, the present study proposes a synergistic photocatalytic mechanism associated with molecular activation to demonstrate selective oxidation pathways at the molecular level.
研究领域:
材料科学
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化学工程
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催化化学
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2019
·
IF 7.65
Wen Tao,Hong Zhong,Xiangbo Pan,Peng Wang,Haiying Wang,Lei Huang
In this paper, Ce-AlOOH were investigated to develop as an adsorbent for removing fluoride. Oxalic acid was selected as an effectively modified reagent to improve the performance of adsorption. Cerium existed in the form of CeO 2 and kept good stability during the adsorption process through XRD, TEM, BET, Raman, and Infrared spectra. The adsorption capacity could be improved with the addition of cerium (62.8 mg/g). Specially, the oxalic acid modification significantly promoted the adsorption capacity to 90 mg/g. There adsorption isotherm and kinetics were estimated independently. These adsorption behaviors were in accordance with the Freundlich model and pseudo-second-order model, indicating that chemisorption was the rate-determining step. the obtained adsorbents all exhibited good recycling performance using oxalic acid as the regeneration reagent. The species of tetravalent cerium was the important adsorption sites. The mechanism was carefully explored by XPS analysis. The fluoride adsorption process can be ascribed to the combined effect of the electrostatic action, surface coordination, and ion exchange between M−OH and F − . Furthermore, modification of oxalic acid exhibited a new easier way to quickly increase M−OH content, which contributed to the dominated adsorption sites.
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
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2022
·Vol. 105
·期 7
·4974-4985
·
IF 4.186
Hang Liu,Xiaofeng Zhao,Yuancheng Teng,Yuxiang Li,Xiayu Zheng,Shanlin Wang,Lang Wu,Pritam Kumar Panda,Rajeev Ahuja
LnPO 4 · 0.667H 2 O rhabdophane has been considered as a potential material for the precipitation of actinides from radioactive waste liquid, owing to its outstanding characteristics of high actinide bearing and easy synthesis in acid solutions. However, a comprehensive understanding of the actinide occupation and the precipitation response of rhabdophane to remove actinides has yet to be established. In this study, the effect of ions concentration and pH values on the detailed precipitation reaction of Ce x Nd 1- x PO 4 · 0.667H 2 O rhabdophane in acid solutions are systematically investigated. Some specific issues such as structural distortion and flexibility, and occupation mechanism are discussed by combining with experiments and density functional theory (DFT) calculation. The results reveal that ions concentration and pH values have a significant impact on the crystallization nucleation step before 12 h. The obtained removal rate of Nd 3+ is more than 99% in pH 1–5 solutions with the ions concentration of 0.05–0.1 mol/L. Moreover, incorporating Nd in CePO 4 · 0.667H 2 O rhabdophane will easily result in the lattice distortion in b -axis. DFT calculation and X-ray photoelectron spectroscopy (XPS) results reveal that Nd is preferentially incorporated in nonhydrated site to form a weaker binding energy of NdO 8 polyhedron.
研究领域:
材料科学
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核化学与放射化学
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DOI
高影响因子
ENVIRONMENTAL ENGINEERING SCIENCE
·
2022
·Vol. 39
·期 1
·56-63
·
IF 2.172
Jie Zhang,Ben Dong,Jing Liu,Wuxu Yang,Sijie Ge,Shilong He
In this article, Mn doping on Ce-based γ-Al2O3 (i.e., Mn-Ce-γ-Al2O3) was synthesized and then employed as catalysts to study the removal of phenol from aqueous solutions through catalytic ozonation process. The results showed that the phenol removal was remarkably increased to 97.50% if Mn-Ce-γ-Al2O3 was adopted as the catalyst. In addition, the kinetic rate of the reaction was increased, approximately, about 1.49 times when using Ce-γ-Al2O3 catalyst with Mn doping. Moreover, X-ray diffraction, transmission electron microscopy, Brunner-Emmet-Teller measurements, and X-ray photoelectron spectroscopy techniques were used to comprehensively characterize the physicochemical properties of the synthesized Mn-Ce-γ-Al2O3 catalyst, including the phases, morphologies, textural properties, and dispersity of the surface active species. More uniform channel mesoporous structures were obtained after Mn doping on Ce-γ-Al2O3, which could enhance the gas-liquid mass transfer rate, surface hydroxyl groups, Ce3+/Ce4+ ratio, and the formation of Mn-Ce solid solution. In this study, the effects of Mn doping on Ce-based γ-Al2O3 on phenol degradation were investigated and the removal mechanisms were suggested for a better understanding of the improved removal efficiency.
研究领域:
环境科学
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催化化学
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2023
·
IF 13.6
Yuanfeng Wei,Jing Zhao,Weijian Yang,Zhiyuan Qiu,Yufen Xia,Zhimin Wang,Yuxin Li,Chengbin Liu
Arsenic contamination of groundwater harms the health of millions of people, especially As(III), which is extremely toxic and difficult to remediate. Herein, we fabricated a reliable La-Ce binary oxide-anchored carbon framework foam (La-Ce/CFF) adsorbent for As(III) deep removal. Its open 3D macroporous structure ensures fast adsorption kinetic. The incorporation of an appropriate amount of La could enhance the affinity of La-Ce/CFF for As(III). The adsorption capacity of La-Ce 10 /CFF reached 40.01 mg/g. It could purify the As(III) concentrations to drinking standard level (< 10 μg/L) over the pH ranges 3–10. It also possessed excellent anti-interference ability to the interfering ions. In addition, it worked reliably in the simulated As(III)-contaminated groundwater and river water. La-Ce 10 /CFF could easily apply in fixed-bed, and La-Ce 10 /CFF (1 g) packed column could purify 4580 BV (36.0 L) of As(III)-contaminated groundwater. When further considering the excellent reusability of La-Ce 10 /CFF, it is a promising and reliable adsorbent for As(III) deep remediation.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
APPLIED SURFACE SCIENCE
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2024
·
IF 6.3
Xueqian Zhao,Weiqiang Zhou,Liming Xu,Danqin Li,Zian Huang,Mingming Zhang,Yize Li,Xiaojing Hao,Jingkun Xu
MoO 3 with Pt-like d-band center electronic structure is an ideal catalyst carrier, but its low conductivity, wide-bandgap and poor photoresponse limits the application of photoelectrocatalysis. Designing doping and oxygen vacancies simultaneously in MoO 3 is a candidate strategy to address some challenges. Herein, a 2D oxygen-vacancies Ce-MoO 3 /Pt (OVs-Ce-MoO 3 /Pt) nanosheet is developed using a two-step method of hydrothermal and chemical reduction. The band gap, optical properties, and methanol adsorption capacity of MoO 3 are well regulated after Ce doping and oxygen vacancy introduction. Profiting by the synergistic promotion of sufficient oxygen vacancies and Ce element, the OVs-Ce-MoO 3 /Pt catalyst exhibits super-efficient photoelectrocatalytic activity (2858 mA mg −1 ) and poisoning-tolerance ability towards methanol oxidation, which is superior to the Ovs-MoO 3 /Pt catalyst (1542 mA mg −1 ) and commercial JM Pt/C catalyst (377 mA mg −1 ). These results indicate that the OVs-Ce-MoO 3 /Pt catalyst can serve as a highly promising catalyst in the field of photoelectrocatalysis.
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
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2018
·
IF 3.794
Lan Wang,Xiaoyan Shu,Facheng Yi,Dadong Shao,Kuibao Zhang,Haibin Zhang,Xirui Lu
A series of Nd and Ce co-doped Gd 2- x Nd x Zr 2- y Ce y O 7 (0.0 ≤ x , y ≤ 2.0) ceramics were rapidly fabricated through spark plasma sintering (SPS) within 3 min. The effects of Nd and Ce contents on the phase composition, lattice parameter , active modes, microtopography and microstructure have been investigated in detail. XRD studies reveal that the compositions corresponding to 0.0 ≤ y ≤ 1.0 show a single phase and beyond 1.0 exhibit multiphase. The lattice parameters increase with elevated Nd and Ce content. The grains are densely packed on each other with cube-like shape, and the elements are almost homogeneously distributed in the compound. This synthetic method provides a simple pathway for the preparation of highly densified single phase ceramic at 1600–1700 ℃ for 3 min under pressure of 80 MPa.
研究领域:
材料科学
·
无机化学
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产品关联
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Yaping Yang,Xuesong Liu,Zhiming Sui,Yanghui Wang,Ping Fang,Peng Jiang,Xiaodong Wu
The purpose of this study is to investigate the interaction of Ce and W species with TiO 2 , Al 2 O 3 and SiO 2 supports, so as to illustrate the influence of supports and distribution of Ce, W species on SCR reaction. It is found that low-temperature activity followed the order of CeW > CeWTi > CeWAl > CeWSi. The reasons for the various activity of the catalyst were investigated by a series of characterization. The low-temperature NH 3 -SCR activity is associated with the surface concentrations of Ce 3+ , oxygen vacancies and active oxygen species, which are dominated by the dispersion and interactions of Ce/W species with the supports. Arising from interactions of Ti 4+ with high-density electron cloud, finely dispersed Ce and W species facilitate the W-Ce synergism and produce more active oxygen. All these contribute toTiO 2 can make Ce and W species in an ideal distribution, so the corresponding catalyst shows excellent NO x conversion of CeWTi catalyst at 200–350 °C. The reaction process observed by in situ DRIFT indicated that the NH 3 -SCR reaction on CeO 2 -WO 3 containing catalysts mainly follow Langmuir-Hinshelwood (L-H) mechanism at low temperature. Based on the analysis of the characterization and reaction process, it is concluded that the control step of NH 3 -SCR reaction at low temperature over CeO 2 -WO 3 containing catalysts is the adsorption and activation of NO x .
研究领域:
催化化学
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环境科学
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产品关联
DOI
高影响因子
CHEMICAL GEOLOGY
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2023
·
IF 3.9
Tao Wu,Yujie Hong,Dongchen Shao,Jiatong Zhao,Zhengye Feng
The impact of the diffuse double-layer on the diffusion of radionuclide anions remains unclear, impeding the application of Archie's law for adsorptive anions. Through-diffusion experiments were carried out to measure the effective diffusion coefficient and distribution coefficient of Ce(III) in the presence of EDTA. A multi-porosity model, in combination with Archie's law, was used to estimate the effective diffusion coefficient. The predominant species, CeEDTA − , exhibited an effective diffusion coefficient of (0.88–1.92) × 10 −11 m 2 /s and the distribution coefficient of (0.81–1.18) × 10 −3 m 3 /kg at the compacted dry density of 1300–1800 kg/m 3 . The accessible porosity, the diffuse double-layer porosity, and the interlayer porosity were analyzed using the multi-porosity model, based on the characterization of bentonite via Scanning electron microscopy with energy dispersive spectrometry, X-ray diffractometer , and Nitrogen-Brunner-Emmett-Teller method. Due to the low external surface area of Zhisin bentonite (27.7–35.3 m 2 /g), the impact of the diffuse double-layer was insignificant on the total and accessible porosities. Additionally, the diffuse double-layer porosity had insignificant impact on the effective diffusion coefficient of CeEDTA − in compacted bentonite, as its value was one order magnitude lower than that of the interlayer porosity and the accessible porosity.
研究领域:
环境科学
·
放射生物学
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产品关联
DOI
高影响因子
Catalysts
·
2019
·Vol. 9
·期 8
·682
·
IF 3.444
Wenjie Sun,Xiaomin Li,Chao Sun,Zhen Huang,Hualong Xu,Wei Shen
Metal organic frameworks (MOFs) have recently been used as precursors of the catalysts for the combustion of volatile organic compounds (VOCs). In the present work, three kinds of CeO2catalysts were successfully synthesized from Ce-MOF-808, Ce-BTC, and Ce-UiO-66, with specific topological structures and coordinate environments. Catalysts with small particle size, stacking mode, and structural defects could be created by pyrolysis of Ce-MOFs, which affects the activity in the toluene combustion significantly. Raman spectra, XPS, and OSC studies were performed to reveal the formation of defect sites. The thermal redox properties were determined by H2-TPR. Catalytic activity tests were conducted on the toluene combustion, and CeO2-MOF-808 showed the best catalytic performance (T90 = 278 °C) due to its having the largest specific surface area, abundant active surface oxygen species, and low-temperature reducibility.Keywords:Ce-MOF;cerium oxide;catalytic combustion of toluene;environmental catalysis;pyrolysis process
研究领域:
材料科学
·
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
·
2024
·
IF 9.6
Liu Cheng,Shi Ying-Zhang,Chen Qi,Ye Bing-Hua,Bi Jin-Hong,Yu Jimmy C.,Wu Ling
Defect engineering in metal organic frameworks (MOFs) has captured significant attention in the field of photocatalysis. A series of UiO-66(Ce) (UiO = University of Oslo) MOFs with different contents of missing-linker defects have been developed for the photocatalytic selective oxidation of benzylamine (BA) and thioanisole (TA) under visible light. The introduction of missing-linker defects promotes the formation of unsaturated Ce sites with a high Ce 3+ content. It also generates a high concentration of oxygen vacancies. In situ Fourier transform infrared spectroscopy (FTIR) results revealed that BA and TA molecules were activated on coordinatively unsaturated Ce sites via the H–N···Ce and the C–S···Ce interactions, respectively. Simulated in situ electron paramagnetic resonance (EPR) data indicate that O 2 activation and reduction occur at coordinatively unsaturated Ce 3+ sites to form ·O 2 – . This is accelerated by the Ce 3+ /Ce 4+ redox cycle associated with the photogenerated electrons. The corresponding photogenerated holes are involved in the deprotonation of the activated BA and TA. The most active sample exhibits 98.4% and 95.5% conversion rates for BA and TA oxidation. Mechanisms for the molecular activation are proposed at the molecular level. Graphical abstract
研究领域:
材料科学
·
催化化学
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产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2021
·
IF 3.712
Ye Zhang,Yong Gao,Peng Wang,Duo Na,Zhenming Yang,Jinsong Zhang
Extraction reactor is a major research area of interest within the field of rare earths extraction and separation. SiC foam offers excellent material characteristics as well as three-dimensional (3-D) reticulated structure; however, very little research has been carried out on its application in extraction reactor so far. In this work, a static mixer reactor based on SiC foam was designed and demonstrated to extract and separate Ce(III) and Pr(III) from nitric acid media by using 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) as extractant. The structure–performance relationship between SiC foam and extraction performance was studied by experiment combined with computational fluid dynamics (CFD) simulation. The experiment data are in good agreement with the simulation results. Contrast experiment by using a Kenics mixer was carried out, and SiC foam shows better extraction and mass transfer performance. Using the optimal structural SiC foam (pore size D = 2.3 mm, open porosity ε = 85%, foam length L = 80 mm), high extraction efficiency η (Pr(III): 94.6%, Ce(III): 88.5%) and separation factor β (2.27) between Ce(III) and Pr(III) is achieved at a high total throughput of 200 mL/min. Besides, overall volumetric mass transfer coefficient K L a of Pr(III) and Ce(III) are 0.519 and 0.378 s −1 at the residence time τ of 3.6 s, respectively, which reach the high level of microchannel reactors and are better than conventional extractors and other static mixers. SiC foam is found to be applicable as a static mixer for efficient and high-throughput extraction and separation of rare earths.
研究领域:
稀土提取
·
分离工程
·
化学工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）