scholarly journals CO Oxidation Capabilities of La- and Nd-Based Perovskites

Fuels ◽  
2022 ◽  
Vol 3 (1) ◽  
pp. 31-43
Author(s):  
Thomas Ruh ◽  
Richard Buchinger ◽  
Lorenz Lindenthal ◽  
Florian Schrenk ◽  
Christoph Rameshan
Keyword(s):  
Co Oxidation ◽  
Ignition Temperature ◽  
Heterogeneous Catalysts ◽  
Catalyst Design ◽  
Co Doping ◽  
Interesting Approach ◽  
Material Choice ◽  
A Site ◽  
Perovskite Type

Catalytic tests to assess the performance of mixed perovskite-type oxides (La0.9Ca0.1FeO3-δ, La0.6Ca0.4FeO3-δ, Nd0.9Ca0.1FeO3-δ, Nd0.6Ca0.4FeO3-δ, Nd0.6Ca0.4Fe0.9Co0.1O3-δ, Nd0.6Ca0.4Fe0.97Ni0.03O3-δ, and LSF) with respect to CO oxidation are presented as well as characterization of the materials by XRD and SEM. Perovskites are a highly versatile class of materials due to their flexible composition and their ability to incorporate dopants easily. CO oxidation is a widely used “probe reaction” for heterogeneous catalysts. In this study, it is demonstrated how tuning the composition of the catalyst material (choice of A-site cation, A-site and B-site doping) greatly influences the activity. Changing the A-site cation to Nd3+ or increasing the concentration of Ca2+ as A-site dopant improves the performance of the catalyst. Additional B-site doping (e.g., Co) affects the performance as well—in the case of Co-doping by shifting ignition temperature to lower temperatures. Thus, perovskites offer an interesting approach to intelligent catalyst design and tuning the specific properties towards desired applications.

scholarly journals Syntheses and Characterization of Novel Perovskite-Type LaScO3-Based Lithium Ionic Conductors

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 299
Author(s):  
Guowei Zhao ◽  
Kota Suzuki ◽  
Masaaki Hirayama ◽  
Ryoji Kanno
Keyword(s):  
Activation Energy ◽  
Ionic Conductivity ◽  
Structure Refinement ◽  
Compositional Analysis ◽  
Unit Cell ◽  
Phase Identification ◽  
Ionic Conductors ◽  
Co Doping ◽  
A Site ◽  
Perovskite Type

Perovskite-type lithium ionic conductors were explored in the (LixLa1−x/3)ScO3 system following their syntheses via a high-pressure solid-state reaction. Phase identification indicated that a solid solution with a perovskite-type structure was formed in the range 0 ≤ x < 0.6. When x = 0.45, (Li0.45La0.85)ScO3 exhibited the highest ionic conductivity and a low activation energy. Increasing the loading of lithium as an ionic diffusion carrier expanded the unit cell volume and contributed to the higher ionic conductivity and lower activation energy. Cations with higher oxidation numbers were introduced into the A/B sites to improve the ionic conductivity. Ce4+ and Zr4+ or Nb5+ dopants partially substituted the A-site (La/Li) and B-site Sc, respectively. Although B-site doping produced a lower ionic conductivity, A-site Ce4+ doping improved the conductive properties. A perovskite-type single phase was obtained for (Li0.45La0.78Ce0.05)ScO3 upon Ce4+ doping, providing a higher ionic conductivity than (Li0.45La0.85)ScO3. Compositional analysis and crystal-structure refinement of (Li0.45La0.85)ScO3 and (Li0.45La0.78Ce0.05)ScO3 revealed increased lithium contents and expansion of the unit cell upon Ce4+ co-doping. The highest ionic conductivity of 1.1 × 10−3 S cm−1 at 623 K was confirmed for (Li0.4Ce0.15La0.67)ScO3, which is more than one order of magnitude higher than that of the (LixLa1−x/3)ScO3 system.

The Catalytic Activity for CO Oxidation and Characterization of Perovskite-type Oxides Catalysts La1+X/2Sr1-x/2Co1-xCuxO3

1996 ◽  
Vol 12 (06) ◽  
pp. 502-507
Author(s):  
Li Xu-Yuan ◽  
◽  
Zhang Zi-Ping ◽  
Ma Jian-Tai ◽  
Zhu Zong-Zhen ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Co Oxidation ◽  
Perovskite Type

Synthesis and characterization of A-site deficient rare-earth doped BaZrxTi1−xO3 perovskite-type compounds

2009 ◽  
Vol 11 (5) ◽  
pp. 1016-1022 ◽  
Author(s):  
C. Ostos ◽  
L. Mestres ◽  
M.L. Martínez-Sarrión ◽  
J.E. García ◽  
A. Albareda ◽  
...  
Keyword(s):  
Rare Earth ◽  
Synthesis And Characterization ◽  
A Site ◽  
Perovskite Type ◽  
Rare Earth Doped

scholarly journals A rational catalyst design of CO oxidation using the bonding contribution equation

2017 ◽  
Vol 53 (58) ◽  
pp. 8106-8109 ◽  
Author(s):  
Ziyun Wang ◽  
P. Hu
Keyword(s):  
Co Oxidation ◽  
Rational Design ◽  
Heterogeneous Catalysts ◽  
Catalyst Design ◽  
Rational Catalyst Design

A rational design of heterogeneous catalysts is an important yet challenging task.

Preparation and characterization of A-site doped Perovskite-type manganese oxides

2013 ◽  
Author(s):  
Yingqun Huang ◽  
Xiong Li ◽  
Xinglai Che ◽  
Hailang Ju
Keyword(s):  
Manganese Oxides ◽  
A Site ◽  
Perovskite Type

Quantitative nano-characterization of heterogeneous catalysts

1995 ◽  
Vol 53 ◽  
pp. 398-399
Author(s):  
P.A. Crozier ◽  
M. Pan
Keyword(s):  
Heterogeneous Catalysts ◽  
Low Dose ◽  
Imaging Techniques ◽  
Structural Features ◽  
Catalyst Characterization ◽  
New Developments ◽  
Double Phase ◽  
Phase Systems ◽  
Dose Imaging

Heterogeneous catalysts can be of varying complexity ranging from single or double phase systems to complicated mixtures of metals and oxides with additives to help promote chemical reactions, extend the life of the catalysts, prevent poisoning etc. Although catalysis occurs on the surface of most systems, detailed descriptions of the microstructure and chemistry of catalysts can be helpful for developing an understanding of the mechanism by which a catalyst facilitates a reaction. Recent years have seen continued development and improvement of various TEM, STEM and AEM techniques for yielding information on the structure and chemistry of catalysts on the nanometer scale. Here we review some quantitative approaches to catalyst characterization that have resulted from new developments in instrumentation.HREM has been used to examine structural features of catalysts often by employing profile imaging techniques to study atomic details on the surface. Digital recording techniques employing slow-scan CCD cameras have facilitated the use of low-dose imaging in zeolite structure analysis and electron crystallography. Fig. la shows a low-dose image from SSZ-33 zeolite revealing the presence of a stacking fault.

Preparation and Characterization of Ag Doped Mn2O3 Nanomaterial for CO Oxidation

2013 ◽  
Vol 2 (3) ◽  
pp. 213-218
Author(s):  
R. K. Kunkalekar ◽  
A. V. Salker
Keyword(s):  
Co Oxidation

Stability and Microstructure Characterization of Barrierless Cu (Sn, C) Films

2014 ◽  
Vol 1052 ◽  
pp. 163-168 ◽  
Author(s):  
Xiao Na Li ◽  
Lu Jie Jin ◽  
Li Rong Zhao ◽  
Chuang Dong
Keyword(s):  
Diffusion Barrier ◽  
Amorphous Layer ◽  
Barrier Effect ◽  
Co Doping ◽  
Cu Alloy ◽  
Large Atom ◽  
Cu Film ◽  
Small Atom ◽  
Lower Resistivity

Thermal stability, adhesion and electronic resistivity of the Cu alloy films with diffusion barrier elements (large atom Sn and small atom C) have been studied. Ternary Cu (0.6 at.% Sn, 2 at.% C) films were prepared by magnetron co-sputtering in this work. The microstructure and resistivity analysis on the films showed that the Cu (0.6 at.% Sn, 2 at.% C) film had better adhesion with the substrate and lower resistivity (2.8 μΩ·cm, after annealing at 600 °C for 1 h). Therefore, the doping of carbon atoms makes less effect to the resistivity by decreasing the amount of the doped large atoms, which results in the decreasing of the whole resistivity of the barrierless structure. After annealing, the doped elements in the film diffused to the interface to form self-passivated amorphous layer, which could further hinder the diffusion between Cu and Si. So thus ternary Cu (0.6 at.% Sn, 2 at.% C) film had better diffusion barrier effect. Co-doping of large atoms and small atoms in the Cu film is a promising way to improve the barrierless structure.

Functional and Structural Characterization of Acquired Pan-Aminoglycoside Resistance 16S rRNA Methyltransferase NpmB1

2021 ◽  
Author(s):  
Akito Kawai ◽  
Masahiro Suzuki ◽  
Kentaro Tsukamoto ◽  
Yusuke Minato ◽  
Yohei Doi
Keyword(s):  
Amino Acid ◽  
16S Rrna ◽  
Amino Acid Identity ◽  
Single Amino Acid ◽  
Aminoglycoside Resistance ◽  
E Coli ◽  
The United Kingdom ◽  
Amino Acid Variant ◽  
A Site

Post-translational methylation of the A site of 16S rRNA at position A1408 leads to pan-aminoglycoside resistance encompassing both 4,5- and 4,6-disubstituted 2-deoxystreptamine (DOS) aminoglycosides. To date, NpmA is the only acquired enzyme with such function. Here, we present function and structure of NpmB1 whose sequence was identified in Escherichia coli genomes registered from the United Kingdom. NpmB1 possesses 40% amino acid identity with NpmA1 and confers resistance to all clinically relevant aminoglycosides including 4,5-DOS agents. Phylogenetic analysis of NpmB1 and NpmB2, its single amino acid variant, revealed that the encoding gene was likely acquired by E. coli from a soil bacterium. The structure of NpmB1 suggests that it requires a structural change of the β6/7 linker in order to bind to 16S rRNA. These findings establish NpmB1 and NpmB2 as the second group of acquired pan-aminoglycoside resistance 16S rRNA methyltransferases.

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