Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 34
·9130-9139
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IF 5.976
Junlei Qi,Minghe Cao,James P. Heath,Julian S. Dean,Hua Hao,Zhonghua Yao,ZhiYong Yu,Hanxing Liu
For single phase dielectric ceramics prepared using a traditional solid state method, the conflict between high dielectric permittivity and low breakdown strength has always limited the improvement of energy storage density. Here, we design a core–shell structure of Sr0.985Ce0.01TiO3 (SCT)@x wt% SiO2 combining a high dielectric permittivity core with an insulating shell material. The sample of x = 3 wt% sintered at 1300 °C has the largest energy storage density ∼2.23 J cm−3. The effects that different amounts of SiO2 have on phase, microstructure, dielectric and energy storage properties were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy with energy dispersive X-ray spectrum (SEM-EDS) and dielectric measurements. As verified by finite element simulations, the energy storage properties are mainly governed by the electric field distribution owing to the introduction of a high dielectric permittivity core (SCT) in a low permittivity shell. The shell material provides an electrical shielding effect around the core, resulting in significant reduction in the field strength within the core material. A comparison of experimental and simulated results is also shown, which is in good agreement with the breakdown properties.
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JOURNAL OF NUCLEAR MATERIALS
·
2015
·
IF 1.865
Kuibao Zhang,Guanjun Wen,Dan Yin,Haibin Zhang
Synroc is recognized as the second generation waste form for the immobilization of high-level radioactive waste (HLW). Zirconolite-rich (CaZrTi 2 O 7 ) Synroc minerals were attempted by self-propagating high-temperature synthesis (SHS) using Fe 2 O 3 , CrO 3 , Ca(NO 3 ) 2 as the oxidants and Ti as the reductant . All designed reactions were ignited and sustained using Ca(NO 3 ) 2 as the oxidant, and zirconolite-rich ceramic matrices were successfully prepared with pyrochlore (Ca 2 Ti 2 O 6 ), perovskite (CaTiO 3 ) and rutile (TiO 2 ) as the minor phases. The sample CN-4, which was designed using Ca(NO 3 ) 2 as the oxidant with TiO 2 /Ti ratio of 7:9, was readily solidified with density of 4.62 g/cm 3 and Vickers hardness of 1052 HV. CeO 2 was successfully stabilized by the CN-4 sample with resultant phase constituent of 2M-CaZrTi 2 O 7 and CaTiO 3 .
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ELECTROPHORESIS
·
2016
·Vol. 37
·期 14
·2097-2105
·
IF 2.482
Ya-Jun Duan,Li-Yun Zhang,Xiao-Feng Guo,Hong Wang
A rapid and robust CE method using a long wavelength fluorescent reagent 1,7-dimethyl-3,5-distyryl-8-phenyl-(2-maleimide)difluoroboradiaza- s -indacene as the labeling reagent has been developed for the simultaneous determination of thiols, including glutathione, cysteine, homocysteine, N -acetylcysteine, cysteinylglycine, and penicillamine. The derivatization reaction was carried out in 14 mmol/L pH 8.5 borate buffer at 30°C for 6 min and the labeled thiols derivatives were separated with the running buffer containing 30 mmol/L pH 7.4 phosphate, 30% v/v acetonitrile and 8 mmol/L SDS within 12 min. Detection limits ranged from 0.4 to 2.4 nmol/L. To demonstrate the capability of this method, it was applied to the analysis of thiols in human urine with recoveries of 92.4–105.6%. The derivatization reaction was much faster at milder conditions, and the analysis was rapider. Moreover, with excitation wavelength at long wavelength region, background interference from samples was reduced effectively. The present method seems to be a potential choice for quantifying thiols in human urine.
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Catalysis Science & Technology
·
2016
·Vol. 6
·期 14
·5656-5667
·
IF 5.287
Fufeng Cai,Guomin Xiao
In this work, a series of Cu–Co–Al catalysts with different Ce loadings were applied to the hydrogenolysis of glycerol to 1,2-propanediol in a fixed-bed flow reactor. The physicochemical properties of the synthesized catalysts were analyzed using BET, N2O chemisorption, SEM, TEM, XRD, H2-TPR, NH3-TPD and XPS techniques. Systematic characterization demonstrated that the incorporation of Ce into the Cu–Co–Al catalyst could effectively restrain the aggregation of active metal species as well as the growth of metallic particles during calcination and reduction, which resulted in the formation of highly dispersed active metals. Large amounts and superior strength of acid sites were present in the Ce-promoted Cu–Co–Al catalysts, as confirmed by NH3-TPD analysis. The reducible nature of the Cu–Co–Al catalyst greatly increased after the addition of Ce. The higher concentration of acid sites, excellent reducibility and highly dispersed active metals were responsible for the superior catalytic activity of the 8Ce/Cu–Co–Al catalyst and it attained 91.6% glycerol conversion and 92.4% 1,2-propanediol selectivity. In addition, the effects of different process parameters such as the solvent, reaction temperature, operating pressure, catalyst loading, glycerol concentration and liquid flow rate on glycerol hydrogenolysis together with the catalyst stability were studied in detail, showing that the Ce-promoted Cu–Co–Al catalyst had high efficiency and stability for glycerol hydrogenolysis.
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APPLIED CATALYSIS A-GENERAL
·
2017
·
IF 4.339
Baohuai Zhao,Rui Ran,Xingguo Guo,Li Cao,Tengfei Xu,Ze Chen,Xiaodong Wu,Zhichun Si,Duan Weng
Mn/Ce/Ti and Mn/Ce/Nb/Ti catalysts were synthesized using a precipitation method and their catalytic activities for NO selective reduction with NH 3 at low temperatures were evaluated. Nb doping not only improved the activity of the catalyst over a wide temperature range but also restricted the generation of NO 2 and N 2 O. The Mn/Ce/Nb/Ti catalyst displayed 100% NO conversion from 150 to 250 °C and >90% N 2 selectivity below 250 °C. The specific surface area of the catalyst was increased and its surface acidity was strengthened after Nb doping. Moreover, Nb doping increased the NO oxidation ability and lowered the NH 3 oxidation activity of the catalyst. All the above factors contributed to enhancing the overall NH 3 -SCR performance of the Mn/Ce/Nb/Ti catalyst compared with that of the Mn/Ce/Ti one. The long-term stability and resistance to H 2 O and SO 2 of the Mn/Ce/Nb/Ti catalyst were also evaluated.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Chunlei Zhang,Guangyan Xu,Yanshuang Zhang,Chuang Chang,Miao Jiang,Luna Ruan,Min Xiao,Zidi Yan,Yunbo Yu,Hong He
Selective catalytic reduction of nitrogen oxides with methane (CH 4 -SCR) has emerged as a promising technology for mitigating exhaust emissions from natural gas vehicles, while its insufficient catalytic activity and durability are key barriers to application. In this study, novel Ce/In-CHA OXZEO catalysts were prepared, demonstrating exceptional catalytic performance and stability in the CH 4 -SCR reaction. Over these OXZEO catalysts, indium species predominantly existed in the form of InO + and In x O y within the CHA zeolite framework, while CeO 2 nanoparticles primarily resided as an external layer. During the CH 4 -SCR reaction, NO oxidation to form NO 2 and nitrate species was triggered by CeO 2 , which further enhanced the activation of CH 4 on InO + sites, thus boosting the low-temperature CH 4 -SCR process by facilitating the formation of the key intermediate CH 3 NO 2 . The synergy between InO + and CeO 2 underscores the exceptional performance and stability of the Ce/In-CHA with a low SiO 2 /Al 2 O 3 ratio in reducing NO x and CH 4 emissions.
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DIAMOND AND RELATED MATERIALS
·
2024
·
IF 4.3
Xiaochen Yu,Xiao He,Xu Zhang,Yadi Peng,Pengfei Zhao,Ziqiao Zhang,Yifan Liu,Lingcheng Zhang,Peng Zhao
Element doping strategies are commonly employed to achieve effective photocatalysts. In this work, a novel form of P and Ce co-doped g-C 3 N 4 nanosheets was synthesized using a one-step thermal polymerization technique, exhibiting remarkable efficiency in the degradation of organic pollutants under visible light. The prepared catalysts underwent comprehensive characterization through XRD, FT-IR, SEM, TEM, BET, XPS, UV–vis, PL, and electrochemical testing. The electronic and optical properties of the catalysts were further elucidated using first-principles density functional theory (DFT). In the photocatalytic experiment of degrading Rhodamine B (RhB), the photocatalytic ability of g-C 3 N 4 nanosheets was improved at different degrees, among which g-C 3 N 4 nanosheets co-doped with P and Ce showed the highest photocatalytic activity, with a degradation efficiency of 90.58 % for RhB. Furthermore, the photocatalytic mechanism was confirmed through free radical capture experiments. This study presents a novel approach for the development of efficient photocatalysts to remove pollutants.
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JOURNAL OF HAZARDOUS MATERIALS
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2024
·
IF 12.2
Shun Qiu,Zhanxun Chen,Ling Yu,Chuying Liu,Chenghan Ji,Pengfei Shen,Sikai Cheng,Hui Qiu,Zhuoyao Fang,Xiaolin Zhang
Herein, a highly efficient As(III) purifier Ce-Mn@N201 with excellent reusability was developed by stepwise precipitating hydrated cerium(IV) oxides (HCO) and hydrated manganese(IV) oxides (HMO) inside N201, a widely-used gel-type anion exchange resin . Owing to confinement of unique nanopores in N201, the in-situ generated nanoparticles (NPs) inside Ce-Mn@N201 were highly dispersed with ultra-small sizes of around 2.6 nm. Results demonstrated that HMO NPs effectively oxidized As(III) to As(V) with the conversion of Mn(IV) to Mn(II), while the generated Mn 2+ was mostly re-adsorbed onto the negatively-charged surface of HMO NPs. During the regeneration process by simple alkaline treatment , the re-adsorbed Mn 2+ was firstly precipitated as (hydr)oxides of Mn(II) and then oxidized to HMO NPs by dissolved oxygen to fully refresh its oxidation capacity. Though HCO NPs mainly served as adsorbent for arsenic, they could partially oxidize As(III) to As(V) at the beginning, while the oxidation capacities continuously diminished with the irreversible conversion of Ce(IV) to Ce(III). In 10 consecutive adsorption-regeneration cycle, Ce-Mn@N201 efficiently decontaminated As(III) from 500 μg/L to below 5 μg/L with Mn 2+ leaching less than 0.3% per batch. During 3 cyclic fixed-bed adsorptions, Ce-Mn@N201 steadily produced 8500–9150 bed volume (BV) and 3150–3350 BV drinkable water from the synthesized and real groundwater, respectively, with Mn leaching in effluent constantly < 100 μg/L.
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POLYMERS FOR ADVANCED TECHNOLOGIES
·
2024
·Vol. 35
·期 6
·e6474
·
IF 3.1
Yi Li,Ning Zhang,Yanchao Zhu,Min Cheng,Shuang Gao
In this work, surface-modified Ce-Zr oxides and ZnO nanoparticles were conveniently prepared by dopamine (Dpa) treatment and then composited with epoxy (EP) by hot pressing. Thermogravimetric analysis (TGA) and UV-shielding properties of the EP composites with surface modification with Dpa-CZ and Dpa-ZnO were measured. The TGA results showed that the modified treated fillers had no loss of heat resistance of the matrix and had an enhancement effect on the initial and maximum decomposition temperatures. In addition, the UV-shielding properties of EP composites after Dpa-CZ and Dpa-ZnO modifications both showed a significant enhancement effect compared to pure EP. The T(UVA) of the 0.5 wt% Dpa-ZnO modified composite decreased to less than 0.017%, and the T(UVB) decreased to less than 0.0059%. The T(UVA) of the 0.5 wt% Dpa-CZ modified composite decreased to less than 15.98%, and the T(UVB) decreased to below 1.14%. The composites have both excellent thermal stability and UV-shielding efficiency.
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Analytical Methods
·
2024
·Vol. 16
·期 22
·3551-3561
·
IF 2.7
Kaigang An,Xin Li,Jia Chen,Shuang Zhang,Jing Xiao,Qing Wang,Hongdeng Qiu
Tetracycline (TC) as a broad-spectrum antibiotic, is widely used in the prevention and treatment of various bacterial diseases. However, its abuse in the livestock industry may lead to interference in human microecology, thereby causing various side effects. In this study, deep eutectic solvents (DESs) were synthesized using L-(–)-threonine (L-(–)-Thr) and cerium nitrate hexahydrate (Ce(NO3)3·6H2O), and later lanthanum nitrate hexahydrate (La(NO3)3·6H2O) was doped to synthesize La–Ce hybrid nanorods. These nanorods can be used for the determination of TC with high sensitivity and selectivity by the colorimetric method. This approach has a linear response to TC between 0.05 μM and 10 μM, with a detection limit of 0.016 μM. In this system, good dispersion provides the substance with a distinct peroxidase activity, which is used to create a colorimetric sensor for detecting TC. Mechanism studies show that the superoxide radical generated by the La–Ce nanomembrane plays a key role in peroxidase catalysis. Finally, the practicality of the method was verified by the determination of TC in food products (milk, pork and honey), which demonstrated that a good recovery rate can be obtained (91.4–102%).
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Dong Wang,Fengqin Tang,Hui Bai,Pengju Wu,Yaju Zhang,Lingyun Fang,Beibei Sun,Chunhui Shi,Libing Hu
The fabrication of advanced electrocatalysts for urea-assisted electrolytic water splitting is of great significance for yielding green hydrogen. In this study, Ce doping a quaternary sea urchin like medium-entropy NiCoFe layered double hydroxide (Ce 1.2 -NiCoFe-LDH) nanoshe et s were obtained by employing a doping engineering strategy. Characterization experimental results confirmed that Ce dopants could modify the oxygen vacancy structure of NiCoFe-LDH, accelerating charge and mass transfer. thereby enhancing the urea decomposition. The electrochemical results indicated that Ce 1.2 -NiCoFe-LDH demonstrated high-efficiency catalysis for UOR, characterized by high intrinsic activity, rapid kinetics, and robust durability. The overpotential of Ce 1.2 -NiCoFe-LDH was only 48 mV at the current density of 10 mA cm −2 , much lower than the commercial IrO 2 (126 mV at 10 mA cm −2 ). The tafel slope of Ce 1.2 -NiCoFe-LDH (62 mV dec −1 ) was also better than those of IrO 2 (88 mV dec −1 ) and NiCoFe-LDH (99 mV dec −1 ). Compared with the commercial IrO 2 , the Ce 1.2 -NiCoFe-LDH exhibited a change of only 3.2 % after a 12-hour chronoamperometric test, indicating an improvement in stability. Impedance comparison between the two hydrotalcites revealed that Ce 1.2 -NiCoFe-LDH possessed lower impedance, potentially enhancing catalytic efficiency. Therefore, this work illustrates that the modulation of oxygen vacancies in electrocatalysts, induced by the heteroatom doping effect, can enhance the electrocatalytic oxidation performance of small molecules for hydrogen production.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Youwei Cheng,Lian Zhu,Yaqiong Gong
Metal-organic frameworks (MOFs) are widely recognized as precursors or sacrificial templates for the synthesis of target catalysts on account of their high porosity and high active surface area . Elemental doping strategy is considered as an effective method for the synthesis of efficient and stable catalysts for electrolytic water. Therefore, in this paper, Ce-doped Ni(OH) 2 nanoparticles and Ni-MOF nanosheets composites were synthesized by electrodeposition using Ni-MOF as precursor. Catalyst Ce–Ni(OH) 2 @Ni-MOF/NF displays excellent OER performance, requiring only 193 mV and 279 mV overpotentials to realize current densities of 10 mA cm −2 and 100 mA cm −2 , respectively, while the UOR performance was very remarkable, only a potential of 1.28 V was demanded to reach a current density of 10 mA cm −2 . In addition, no obvious change in the overpotential was noticed during the stability test of 16 h, indicating good stability of Ce–Ni(OH) 2 @Ni-MOF/NF. This study provides a meaningful reference for the design of an efficient and stable environmental friendly electrocatalyst .
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