Correlation between Catalyst Surface Structure and Polypropylene Tacticity in Ziegler−Natta Polymerization System†

2001 ◽  
Vol 105 (18) ◽  
pp. 3922-3927 ◽  
Author(s):  
Seong Han Kim ◽  
Gabor A. Somorjai
Keyword(s):  
Surface Structure ◽  
Catalyst Surface ◽  
Polymerization System

Enhancing electrocatalytic nitrogen reduction to ammonia with rare earth (La, Y, Sc) on high-index faceted platinum alloy concave nanocubes

2021 ◽  
Author(s):  
Yu-Jie Mao ◽  
Feng Liu ◽  
You-Hu Chen ◽  
Xin Jiang ◽  
Xinsheng Zhao ◽  
...  
Keyword(s):  
Rare Earth ◽  
Surface Structure ◽  
Catalyst Surface ◽  
High Index ◽  
Structure Effect ◽  
Structure Dependence ◽  
Nitrogen Reduction ◽  
Platinum Alloy ◽  
Atomic Arrangement ◽  
Rare Earth La

Surface structure effect is the key subject in electrocatalysis, and consists of the structure dependence of interaction between reaction molecules and catalyst surface in specifying the surface atomic arrangement, chemical...

On the Catalyst Surface Structure

1949 ◽  
Vol 17 (12) ◽  
pp. 1348-1349
Author(s):  
Shou‐Chu Liang
Keyword(s):  
Surface Structure ◽  
Catalyst Surface

Information on catalyst surface structure from crystallite morphologies observed by scanning electron microscopy (SEM)

1992 ◽  
Vol 15 (1-2) ◽  
pp. 123-131 ◽  
Author(s):  
S. C. Parker ◽  
P. J. Lawrence ◽  
C. M. Freeman ◽  
S. M. Levine ◽  
J. M. Newsam
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Surface Structure ◽  
Catalyst Surface ◽  
Scanning Electron

scholarly journals Modifying the Surface Structure of Perovskite-Based Catalysts by Nanoparticle Exsolution

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 268 ◽  
Author(s):  
Lorenz Lindenthal ◽  
Raffael Rameshan ◽  
Harald Summerer ◽  
Thomas Ruh ◽  
Janko Popovic ◽  
...  
Keyword(s):  
Transition Metal ◽  
Surface Structure ◽  
Catalyst Surface ◽  
Nano Particles ◽  
Nominal Composition ◽  
In Situ Xrd ◽  
Highly Active ◽  
Catalytically Active ◽  
Co Nanoparticles ◽  
Perovskite Type

In heterogeneous catalysis, surfaces decorated with uniformly dispersed, catalytically-active (nano)particles are a key requirement for excellent performance. Beside standard catalyst preparation routines—with limitations in controlling catalyst surface structure (i.e., particle size distribution or dispersion)—we present here a novel time efficient route to precisely tailor catalyst surface morphology and composition of perovskites. Perovskite-type oxides of nominal composition ABO3 with transition metal cations on the B-site can exsolve the B-site transition metal upon controlled reduction. In this exsolution process, the transition metal emerges from the oxide lattice and migrates to the surface where it forms catalytically active nanoparticles. Doping the B-site with reducible and catalytically highly active elements, offers the opportunity of tailoring properties of exsolution catalysts. Here, we present the synthesis of two novel perovskite catalysts Nd0.6Ca0.4FeO3-δ and Nd0.6Ca0.4Fe0.9Co0.1O3-δ with characterisation by (in situ) XRD, SEM/TEM and XPS, supported by theory (DFT+U). Fe nanoparticle formation was observed for Nd0.6Ca0.4FeO3-δ. In comparison, B site cobalt doping leads, already at lower reduction temperatures, to formation of finely dispersed Co nanoparticles on the surface. These novel perovskite-type catalysts are highly promising for applications in chemical energy conversion. First measurements revealed that exsolved Co nanoparticles significantly improve the catalytic activity for CO2 activation via reverse water gas shift reaction.

Surface Structure of the Spores of Glugea Weissenbergi

1969 ◽  
Vol 27 ◽  
pp. 238-239
Author(s):  
Sanford H. Vernick ◽  
Anastasios Tousimis ◽  
Victor Sprague
Keyword(s):  
Electron Microscope ◽  
Surface Structure ◽  
Transmission Electron Microscope ◽  
Mature Spore ◽  
Spore Surface ◽  
Sectioned Material ◽  
Transmission Electron ◽  
Surface Detail

Recent electron microscope studies have greatly expanded our knowledge of the structure of the Microsporida, particularly of the developing and mature spore. Since these studies involved mainly sectioned material, they have revealed much internal detail of the spores but relatively little surface detail. This report concerns observations on the spore surface by means of the transmission electron microscope.

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