scholarly journals Simultaneous sulfidation of Mo and Co oxides supported on Au(111)

2021 ◽  
Vol 23 (14) ◽  
pp. 8403-8412
Author(s):  
M. K. Prabhu ◽  
I. M. N. Groot
Keyword(s):  
Model Catalyst ◽  
Oxide Precursor

Co-Promoted MoS2 model catalyst for fundamental hydrodesulfurization studies can be synthesized from a mixed Co and Mo oxide precursor.

High-speed visualization of metal oxide precursor in multiphase AC arc during nanoparticle formation

2020 ◽  
Vol 59 (SH) ◽  
pp. SHHC08 ◽  
Author(s):  
Manabu Tanaka ◽  
Yuki Saito ◽  
Hiroki Maruyama ◽  
Takayuki Watanabe
Keyword(s):  
Metal Oxide ◽  
High Speed ◽  
Nanoparticle Formation ◽  
Oxide Precursor ◽  
Ac Arc

Diffusion of Heavy Oil in SiO2 Model Catalyst and FCC Catalyst

2012 ◽  
Vol 550-553 ◽  
pp. 158-163 ◽  
Author(s):  
Zi Yuan Liu ◽  
Sheng Li Chen ◽  
Peng Dong ◽  
Xiu Jun Ge
Keyword(s):  
Diffusion Coefficient ◽  
Pore Size ◽  
Effective Diffusion Coefficient ◽  
Pore Diameter ◽  
Effective Diffusion ◽  
Model Catalyst ◽  
Average Pore ◽  
Diffusion Factor ◽  
Fcc Catalyst ◽  
Fcc Catalysts

Through the measured effective diffusion coefficients of Dagang vacuum residue supercritical fluid extraction and fractionation (SFEF) fractions in FCC catalysts and SiO2model catalysts, the relation between pore size of catalyst and effective diffusion coefficient was researched and the restricted diffusion factor was calculated. The restricted diffusion factor in FCC catalysts is less than 1 and it is 1~2 times larger in catalyst with polystyrene (PS) template than in conventional FCC catalyst without template, indicating that the diffusion of SFEF fractions in the two FCC catalysts is restricted by the pore. When the average molecular diameter is less than 1.8 nm, the diffusion of SFEF fractions in SiO2model catalyst which average pore diameter larger than 5.6 nm is unrestricted. The diffusion is restricted in the catalyst pores of less than 8 nm for SFEF fractions which diameter more than 1.8 nm. The tortuosity factor of SiO2model catalyst is obtained to be 2.87, within the range of empirical value. The effective diffusion coefficient of the SFEF fractions in SiO2model catalyst is two orders of magnitude larger than that in FCC catalyst with the same average pore diameter. This indicate that besides the ratio of molecular diameter to the pore diameter λ, the effective diffusion coefficient is also closely related to the pore structure of catalyst. Because SiO2model catalyst has uniform pore size, the diffusion coefficient can be precisely correlated with pore size of catalyst, so it is a good model material for catalyst internal diffusion investigation.

A Novel Nitrile Oxide Precursor; 2-Methyl-4-nitro-5(2H)-isoxazolone

Heterocycles ◽  
1992 ◽  
Vol 34 (8) ◽  
pp. 1511 ◽  
Author(s):  
Masahiro Ariga ◽  
Suguru Higashida ◽  
Hiroko Nakashima ◽  
Yasuo Tohda ◽  
Keita Tani ◽  
...  
Keyword(s):  
Nitrile Oxide ◽  
Oxide Precursor

scholarly journals Inverse single-site Fe1(OH)X/Pt(111) model catalyst for preferential oxidation of CO in H2

Nano Research ◽  
2021 ◽  
Author(s):  
Chunlei Wang ◽  
Heloise Tissot ◽  
Markus Soldemo ◽  
Junling Lu ◽  
Jonas Weissenrieder
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Redox Properties ◽  
Model Catalyst ◽  
Single Site ◽  
Oxide Nanoparticles ◽  
Preferential Oxidation ◽  
Oxidation Of Co ◽  
Reaction Conditions ◽  
Preferential Oxidation Of Co

AbstractInverse oxide/metal model systems are frequently used to investigate catalytic structure-function relationships at an atomic level. By means of a novel atomic layer deposition process, growth of single-site Fe1Ox on a Pt(111) single crystal surface was achieved, as confirmed by scanning tunneling microscopy (STM). The redox properties of the catalyst were characterized by synchrotron radiation based ambient pressure X-ray photoelectron spectroscopy (AP-XPS). After calcination treatment at 373 K in 1 mbar O2 the chemical state of the catalyst was determined as Fe3+. Reduction in 1 mbar H2 at 373 K demonstrates a facile reduction to Fe2+ and complete hydroxylation at significantly lower temperatures than what has been reported for iron oxide nanoparticles. At reaction conditions relevant for preferential oxidation of CO in H2 (PROX), the catalyst exhibits a Fe3+ state (ferric hydroxide) at 298 K while re-oxidation of iron oxide clusters does not occur under the same condition. CO oxidation proceeds on the single-site Fe1(OH)3 through a mechanism including the loss of hydroxyl groups in the temperature range of 373 to 473 K, but no reaction is observed on iron oxide clusters. The results highlight the high flexibility of the single iron atom catalyst in switching oxidation states, not observed for iron oxide nanoparticles under similar reaction conditions, which may indicate a higher intrinsic activity of such single interfacial sites than the conventional metal-oxide interfaces. In summary, our findings of the redox properties on inverse single-site iron oxide model catalyst may provide new insights into applied Fe-Pt catalysis.

Effects of molecular dispersion state of surface Ti species on ethylene-propylene copolymerization with TiCl3-based Ziegler-Natta model catalyst

2010 ◽  
Vol 18 (9) ◽  
pp. 834-838 ◽  
Author(s):  
Toshiaki Taniike ◽  
Shougo Takahashi ◽  
Toru Wada ◽  
Iku Kouzai ◽  
Minoru Terano
Keyword(s):  
Model Catalyst ◽  
Ethylene Propylene ◽  
Molecular Dispersion ◽  
Dispersion State

Reactivity of Oxide Precursor States on Ru(0001)

2006 ◽  
Vol 110 (28) ◽  
pp. 13912-13919 ◽  
Author(s):  
Raoul Blume ◽  
Wolfgang Christen ◽  
Horst Niehus
Keyword(s):  
Oxide Precursor ◽  
Precursor States
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