Catalysts
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2019
·Vol. 9
·期 3
·218
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IF 3.444
Shaoxia Guo,Guilong Liu,Tong Han,Ziyang Zhang,Yuan Liu
Owing to the outstanding catalytic performance for higher alcohol synthesis, Ga-Co catalysts have attracted much attention. In view of their unsatisfactory stability and alcohol selectivity, herein, K-modulated Co nanoparticles trapped in La-Ga-O catalysts were prepared by the reduction of La1−xKxCo0.65Ga0.35O3perovskite precursor. Benefiting from the atomic dispersion of all the elements in the precursor, during the reduction of La1−xKxCo0.65Ga0.35O3, Co nanoparticles could be confined into the K-modified La-Ga-O composite oxides, and the confinement of La-Ga-O could improve the anti-sintering performance of Co nanoparticles. In addition, the addition of K modulated parts of La-Ga-O into La2O3, which ameliorated the anti-carbon deposition performance. Finally, the addition of K increased the dispersion of cobalt and provided more electron donors to metallic Co, resulting in a high activity and superior selectivity to higher alcohols. Benefiting from the above characteristics, the catalyst possesses excellent activity, good selectivity, and superior stability.Keywords:perovskite-type oxide (PTO);cobalt;gallium;potassium;higher alcohols;syngas
研究领域:
化学工程
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催化材料
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
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2020
·
IF 6.182
Siran Zhang,Kang An,Shuangshuang Li,Ziyang Zhang,Ruolin Sun,Yuan Liu
A new scheme for constructing bi-active sites of highly dispersed Pt and oxygen vacancies on a catalyst was put forward in this study. Pt/LaCo x Ni 1−x O 3 /SiO 2 was synthesized by reducing LaCo x Ni 0.87−x Pt 0.13 O 3 with the structure of perovskite loaded on silica. The catalytic performance for carbon monoxide oxidation over the catalysts were studied. The catalysts were characterized via using XRD, XPS, XAFS, N 2 adsorption–desorption, H 2 -TPR, TEM, O 2 and CO-TPD techniques. The results pointed out that nanocrystal lines of LaCo x Ni 0.87−x Pt 0.13 O 3 were supported on SiO 2 . Pt clusters could be formed through reduction process at 300 °C and highly dispersed on catalyst’s surface, and the catalyst transformed to Pt/LaCo x Ni 1−x O 3 /SiO 2 ; at the same time, oxygen vacancies also formed on the surface of LaCo x Ni 1−x O 3 . The catalytic test revealed that LaCo 0.44 Ni 0.43 Pt 0.13 O 3 /SiO 2 displayed high activity and good stability for the oxidation of CO. The highly dispersed closely contact bi-active sites, the confinement of oxygen vacancies and strong interaction between Pt clusters and support were responsible for the significant catalytic activity and stability of LaCo 0.44 Ni 0.43 Pt 0.13 O 3 /SiO 2 catalyst.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2020
·
IF 4.65
Xinyi Zhang,Jian-Feng Sun
An intriguing novel perovskite-type Cs 4 Mg 3 CaF 12 : Eu 2+ phosphor with desirable properties for potential application in the field of white light-emitting diodes was first time synthesized. The Rietveld structural refinement, scanning electron microscopy and high resolution transmission electron microscopy were used to determine the crystallographic parameters, morphology and microstructure of Cs 4 Mg 3 CaF 12 : Eu 2+ phosphor. The first principle calculation based on the density functional theory further provided a theoretical understanding of the band structure for the undoped Cs 4 Mg 3 CaF 12 and indicated that it has a large direct band gap of 7.1 eV. Upon the excitation of Cs 4 Mg 3 CaF 12 : Eu 2+ phosphor in the broad range of 250–450 nm, the bright blue light emission was observed with the maximum at 474 nm and a full width at half-maximum of 2808 cm −1 that was attributed to the electric-dipole allowed 4f 6 5 d 1 →4f 7 transition of Eu 2+ ions. Based on the Dexter’s theory, the concentration quenching mechanism among Eu 2+ in the Cs 4 Mg 3 CaF 12 : Eu 2+ phosphor was validated to be the dipole-dipole interaction, and the critical distance was determined to be 23.34 Å. On the basis of temperature-dependent luminescence measurement, an analysis of the origins of thermal quenching behavior was presented. The Cs 4 Mg 3 CaF 12 : Eu 2+ phosphor not only has favorable thermal stability with emission intensity reduction by 20% at T = 473 K in reference to the room temperature level, but also shows the integrated PL intensity 95% as high as that of BaMgAl 10 O 17 : Eu 2+ , internal quantum efficiency of 64% and color purity of 85%. The results of this work indicate that the blue-emitting Cs 4 Mg 3 CaF 12 : Eu 2+ phosphor with promising luminescence properties has a capacity for incorporation as a component to the near-UV based phosphor-converted WLEDs.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
·
IF 11.698
Fan Fang,Nengjie Feng,Lei Wang,Jie Meng,Geng Liu,Peng Zhao,Pengfei Gao,Jing Ding,Hui Wan,Guofeng Guan
Perovskite-type macro/mesoporous nanotube shows large specific surface area and high utilization of catalytic sites, which gives rise to the enhancement of catalytic activity and broaden their application. In this work, perovskite-type La 1-x K x FeO 3-δ nanotubes were prepared for efficient soot oxidation by a simple electrospinning technique following calcination. The as-prepared samples were characterized by XRD, FI-IR, FE-SEM, TEM, XPS, N 2 adsorption-desorption, H 2 -TPR and O 2 -TPD techniques to investigate the physical-chemical properties. A certain amount of K + doped in to LaFeO 3-δ nanotubes sample could inhibit the growth of crystallites during the calcination at a high temperature, which could prevent the destruction of macro/mesoporous tubular structure and contribute to the more contact between soot particles and active sites. Meanwhile, it could also bring about the higher oxygen vacancy density responsible for the enhancement of redox abilities. However, excessive doping of K + could lead to the collapsing of macro/mesoporous tubular structure, ascribable to the formation of low-melting compounds or eutectics with other components of the catalyst, which would have a negative influence on the catalytic performance. The performance for soot catalytic oxidation was evaluated in a temperature programmed oxidation device using O 2 (without or with NO) as oxidant. Among the as-prepared catalysts, the well-structured La 0.8 K 0.2 FeO 3-δ nanotubes catalyst is the best candidate for soot removal.
研究领域:
材料科学
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环境催化
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
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2023
·Vol. 13
·期 1
·131
·
IF 3.9
Jingwei Wang,Xiaocen Liang,Zifan Xing,Haitao Chen,Yang Li,Da Song,Fang He
As a novel reaction mode of oxidative dehydrogenation of ethane to ethylene, the chemical looping oxidative dehydrogenation (CL-ODH) of ethane to ethylene has attracted much attention. Instead of using gaseous oxygen, CL-ODH uses lattice oxygen in an oxygen carrier or redox catalyst to facilitate the ODH reaction. In this paper, a perovskite type redox catalyst LaMnO3+δwas used as a substrate, Ce3+with different proportions was introduced into its A site, and its CL-ODH reaction performance for ethane was studied. The results showed that the ratio of Mn4+/Mn3+on the surface of Ce-modified samples decreased significantly, and the lattice oxygen species in the bulk phase increased; these were the main reasons for improving ethylene selectivity. La0.7Ce0.3MnO3showed the best performance during the ODH reaction and showed good stability in twenty redox cycle tests.Keywords:chemical looping oxidative dehydrogenation;LaMnO3;Ethane;perovskite type redox catalyst
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
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2017
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IF 4.857
Zhongxia Wang,Yang Lu,Hai-Peng Chen,Jia-Zhen Ge
In this report, two new hybrid organic–inorganic perovskite-type compounds, (IBA)CdBr3 (1; IBA = isobutylammonium cation, i-C4H9-NH3) and (IBA)2CdBr4 (2), have been successfully synthesized by reasonable modulation of the ratio of the reactants. 1 with a one-dimensional (1D) chained structure presents sequential solid-state phase transitions, and 2 with a two-dimensional (2D) layered structure undergoes triple structural phase transitions. The phase transitions are attributable to the stepwise ordering process of the organic IBA cation of the title compounds, which also exhibit temperature-dependent dielectric transitions and dielectric anisotropies. Among the different structural environments, the dynamic motions of organic cations show distinct differences, driving the variation of physical properties.
研究领域:
材料科学
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物理化学
✓ 已验证
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
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2018
·Vol. 47
·期 48
·17276-17284
·
IF 4.099
Chun Chen,Ruoyu Fan,Wanbing Gong,Haimin Zhang,Guozhong Wang,Huijun Zhao
Water is inevitably associated with the production of bio-derived platform molecules, but most supported metallic catalysts have poor water compatibility. Although there have been a great number of investigations regarding the hydrogenation of bio-derived unsaturated compounds in the organic phase, the reactions that proceed in water are still quite challenging. Herein, we report the synthesis of a supported nickel catalyst (Ni-LN650) by the reduction of the perovskite-type oxide LaNiO3 precursor at 650 °C. The derived catalyst affords attractive activity in the hydrogenation of furfural by using water as the reaction medium, in which furfural is completely converted into tetrahydrofurfuryl alcohol with the highest productivity of 289.7 mmol gNi−1 h−1 at 120 °C and 1 MPa of H2 within 5 h of reaction. The Ni-LN650 catalyst also exhibits good stability and renewability in a cycle test, stemming from the self-regeneration peculiarity of the perovskite-type oxide precursor. Moreover, the catalyst can also demonstrate high activity in the aqueous-phase hydrogenation of various aldehydes, alkenes and carboxylic acids in a series of experiments. Due to the merits of usability in water, the renewability and wide application scope, the Ni-LN650 catalyst can be treated as a promising candidate for the catalytic conversion of bio-derived platform molecules into high value-added fuels and chemicals.
研究领域:
催化化学
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可再生资源转化
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绿色化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials Advances
·
2022
·Vol. 3
·期 15
·6171-6178
·
IF 0
Mingsheng Cai,Tianchun Lang,Tao Han,Damir Valiev,Shuangqiang Fang,Houjiang You,Bitao Liu,Ling Du,Zichao Xu,Elena F. Polisadova
Investigating narrow-band green emitting phosphors with high efficiency and good thermal stability is the main goal of the present light-emitting diode (LED) display research. Here, Ba1−xCaxScO2F:0.001Bi3+,0.001K+ (x = 0–0.12) perovskite phosphors, emitting narrow green light excited by a 415 nm chip, were developed using the cation substitution design strategy. The effects of Ca2+ substitution for Ba2+ in the Ba1−xCaxScO2F:0.001Bi3+,0.001K+ crystal structures and photoluminescence properties were investigated. All the phosphors show the cubic perovskite-type structure in the space group Pm3m. The evolution of the cell parameters and the Ba/Ca/K/Bi–O bond lengths were evaluated. The phosphors with the internal quantum efficiency of 77.4% exhibit bright green emission peaking at 510 nm under 415 nm chip excitation. The improvement of luminescence efficiency and thermal stability was discussed in detail in relation to the local structure variation. The cation substitution design strategy mentioned here can become an important approach to realize the spectral modulation through controlling the micro-environment in the lattice for excellent LED backlight displays.
研究领域:
材料科学
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光学工程
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无机化学
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固体物理
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显示技术
✓ 已验证
DOI
Nano Select
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2023
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IF 0
Jianyi Xu,Guofang Zhang,Xin Zhao,Feng Hu,Dandan Ke
In this study, the perovskite-type oxide LaFeO 3 is treated by electroless Ni deposition with different reaction time and the electrochemical properties of the resulting material are investigated as the anode for MH-Ni batteries. XRD, SEM, and TEM measurements reveal a uniform deposition of crystalline nickel on the oxide surface and a clear increase in the amount of Ni coating with the deposition time. The electrochemical analysis shows that the electroless deposition can significantly improve the maximum discharge capacity of the battery. Furthermore, the coated electrodes exhibit excellent activation performance and superior cyclic stability. With the increase in the reaction temperature, improvements in the discharge ability, exchange current density, and diffusing coefficient of hydrogen are also observed.
研究领域:
材料科学
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电化学
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能源技术
✓ 已验证
DOI
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Zicheng Shao,Qiuwan Shen,Haoran Ding,Yaowei Jiang,Shian Li,Guogang Yang
The perovskite-type metal oxides SrCo 1-x Cu x O 3-δ (x = 0, 0.2, 0.4, 0.6, 0.8, 1) powders, synthesized by ethylenediaminetetraacetic acid (EDTA) sol-gel method, were investigated for hydrogen production from methanol steam reforming (MSR). The synthesized catalysts were characterized by a scanning X-ray diffraction (XRD), an energy-dispersive X-ray spectroscope (EDS), scanning electron microscopy (SEM), Brunauer-Emmett-Teller specific area (BET), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The XPS results reveal that the perovskite structure of the catalyst sample after reduction treatment is destroyed, resulting in significant changes in oxygen species and the element chemical environment, which is consistent with the XRD results. The experimental results show that the doping content of cobalt and the reaction conditions have affect the catalytic performance of the catalysts. SrCo 0.8 Cu 0.2 O 3-δ displays the maximum hydrogen production (about 4.6 × 10 −3 mol/gcat/min). The Co-doping in the B-site may have an influence on the water-gas shift reaction, which leads to changes in the CO/CO 2 selectivity in the gas products. The optimum reaction conditions (the reaction temperature = 600 °C; the molar ratio of water to methanol (W/M) = 2: 1; the feed flow rate = 3 ml/h) with the best comprehensive catalytic performance were determined by MSR experiments. In addition, the morphological characteristics of porous structure, small particle size, and rough surface contribute to the improvement of the catalytic performance of the catalyst in the MSR for H 2 production.
研究领域:
材料科学
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化学工程
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能源科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2020
·
IF 4.65
Wenlong Huang,Yushi Ding,Ying Li,Zezhong Wang
Ba 3 Ca 1·18 Nb 1·82 O 9-δ (BCN18), which has a high conductivity and protonic conductive dominant above 600 °C, is regarded as a promising double perovskite-type proton conductor for solid oxide fuel cells, catalysis, and electrochemical sensors . To further increase the conduction properties of the double perovskite-type proton conductor, it can be considered to decrease the electronegativities of A and B site elements. In this study, Ba and Ta, which have lower electronegativities than those of Ca and Nb, were introduced to totally substitute Ca and Nb. The double perovskite-type proton conductor Ba 4·3 Ta 1·7 O 8.55 (BBT30) was prepared by solid-state sintering. We found that the total conductivities increased linearly with the increase of the temperature, with the total conductivities being in the range of 1.2 × 10 −5 −8.7 × 10 −4 S cm −1 in humid air at 400 °C−800 °C; the estimated activation energy of proton was obviously lower than those of oxide ion and hole. The standard molar hydration enthalpy of BBT30 was calculated to be −79.9 kJ/mol. Additionally, the transport numbers were determined systematically by defect equilibria model. Our results indicated that both the transport numbers of oxide ion and hole remarkably increased with increasing oxygen partial pressure, while the protonic conduction was always predominant in those atmospheric conditions, with the protonic transport number being 0.64 at 700 °C, and it was significantly higher than those of other double perovskite-type proton conductors. This indicates that BBT30 is an excellent candidate for an electrochemical sensor, and our work has demonstrated a new direction in developing a high conductivity and protonic transport number perovskite-type proton conductor.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2023
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IF 6.4
Zhishan Li,Meilan Peng,Xiaoxin Zhang,Lizhong Zhang,Jianhui Li,Yifei Sun
Various perovskite-type materials have been developed and applied in the field of solid oxide fuel cells (SOFCs). The perovskite oxides prepared by the traditional solid-state method usually need to be calcined at a temperature higher than 1000 °C. Herein, a modified solvothermal synthesis is proposed to prepare the La0.43Ca0.37Ti0.94Ni0.06O3−δ (LCTNi) anode at 800 °C. Compared to the material with identical composition synthesized by the solid-state method (denoted as LCTNi-ss), LCTNi synthesized at the lower temperature possesses smaller particle size, greater specific surface area, higher total conductivity, and better interfacial contact with the electrolyte. The single cell assembled with the LCTNi anode exhibits desirable electrochemical performance using wet H2 as fuel. The maximum power density is as high as ∼425 mW cm–2 at 800 °C in 3% H2O/97% H2 (∼2.5 times higher than that of the LCTNi-ss anode single cell). The boosted performance is mainly attributed to the facilitated gas diffusion process at the LCTNi anode side.
研究领域:
材料科学
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能源工程
✓ 已验证
DOI
高影响因子
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