ChemInform Abstract: Active Site Elucidation in Heterogeneous Catalysis via in situ X-Ray Spectroscopies

ChemInform ◽  
2012 ◽  
Vol 43 (42) ◽  
pp. no-no
Author(s):  
Adam F. Lee
Keyword(s):  
Heterogeneous Catalysis ◽  
Active Site ◽  
X Ray

scholarly journals A Cobalt-Iron Double-Atom Catalyst for the Oxygen Evolution Reaction

2019 ◽  
Author(s):  
Lichen Bai ◽  
Chia-Shuo Hsu ◽  
Duncan Alexander ◽  
Hao Ming Chen ◽  
Xile Hu
Keyword(s):  
Oxygen Evolution ◽  
Active Site ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Single Atom ◽  
X Ray ◽  
Highly Active ◽  
Cobalt Iron ◽  
X Ray Absorption

Single atom catalysts exhibit well-defined active sites and potentially maximum atomic efficiency. However, they are unsuitable for reactions that benefit from bimetallic promotion such as the oxygen evolution reaction (OER) in alkaline medium. Here we show that a single atom Co precatalyst can be in-situ transformed into a Co-Fe double atom catalyst for OER. This catalyst exhibits one of the highest turnover frequencies among metal oxides. Electrochemical, microscopic, and spectroscopic data including those from operando X-ray absorption spectroscopy, reveal a dimeric Co-Fe moiety as the active site of the catalyst. This work demonstrates double-atom catalysis as a promising approach for the developed of defined and highly active OER catalysts.

X-ray absorption fine structure measurements on Ru–Zn/ZSM-5 during heterogeneous catalysis using an in situ spectroscopic cell

2020 ◽  
Vol 2 (3) ◽  
pp. 034002
Author(s):  
Lijia Liu ◽  
Peng He ◽  
Yujian Xia ◽  
Hua Song ◽  
Lo-Yueh Chang ◽  
...  
Keyword(s):  
Fine Structure ◽  
Heterogeneous Catalysis ◽  
X Ray ◽  
Absorption Fine ◽  
X Ray Absorption

scholarly journals A Cobalt-Iron Double-Atom Catalyst for the Oxygen Evolution Reaction

2019 ◽  
Author(s):  
Lichen Bai ◽  
Chia-Shuo Hsu ◽  
Duncan Alexander ◽  
Hao Ming Chen ◽  
Xile Hu
Keyword(s):  
Oxygen Evolution ◽  
Active Site ◽  
Oxygen Evolution Reaction ◽  
Active Sites ◽  
Single Atom ◽  
X Ray ◽  
Highly Active ◽  
Cobalt Iron ◽  
X Ray Absorption

Single atom catalysts exhibit well-defined active sites and potentially maximum atomic efficiency. However, they are unsuitable for reactions that benefit from bimetallic promotion such as the oxygen evolution reaction (OER) in alkaline medium. Here we show that a single atom Co precatalyst can be in-situ transformed into a Co-Fe double atom catalyst for OER. This catalyst exhibits one of the highest turnover frequencies among metal oxides. Electrochemical, microscopic, and spectroscopic data including those from operando X-ray absorption spectroscopy, reveal a dimeric Co-Fe moiety as the active site of the catalyst. This work demonstrates double-atom catalysis as a promising approach for the developed of defined and highly active OER catalysts.

Design of a high-pressure and high-temperature cell for operando X-ray absorption spectroscopy in heterogeneous catalysis

2011 ◽  
Vol 1 (SRMS-7) ◽  
Author(s):  
A. Rochet ◽  
V. Moizan ◽  
V. Briois ◽  
C. Pichon
Keyword(s):  
Heterogeneous Catalysis ◽  
Absorption Spectroscopy ◽  
Working Conditions ◽  
Elevated Temperatures ◽  
Fixed Bed ◽  
Absorption Cell ◽  
X Ray ◽  
Fixed Bed Reactors ◽  
X Ray Absorption

A new X-ray absorption cell dedicated to in situ and operando experiments in heterogeneous catalysis has been built and tested. It allows measurement of X-ray absorption spectroscopy (XAS) spectra in transmission mode under the flow of various gas mixtures at elevated temperatures (600°C) and pressures (50 bar). The working conditions are representative of phenomena that take place in fixed bed reactors.

Study on Effect Recyclability of Ru/Bentonite-TiO2 Catalysts in Glycerol Hydrogenolysis Reaction Using X-Ray Photoelectron Spectroscopy (XPS)

2012 ◽  
Vol 620 ◽  
pp. 289-294 ◽  
Author(s):  
Noraini Hamzah ◽  
Nor Asikin Mohamad Nordin ◽  
Wan Nor Roslam Wan Isahak ◽  
Mohamad Bin Kassim ◽  
Mohd Ambar Yarmo
Keyword(s):  
Active Site ◽  
Photoelectron Spectroscopy ◽  
Hydrogen Pressure ◽  
Catalytic Performance ◽  
Atomic Ratio ◽  
Xps Analysis ◽  
X Ray ◽  
Glycerol Hydrogenolysis ◽  
Repeated Runs

Recyclability effect on catalytic performance of Ru supported on the mixture of bentonite-TiO2 for the hydrogenolysis of glycerol was investigated under reaction condition of 150°C, 2.0 MPa hydrogen pressure and 7 h reaction time. Interestingly, the recovered Ru/bentonite-TiO2 catalyst was found to be active in the repeated runs. The conversion of glycerol increased in the four successive reactions as follows: 61.3%, 65.6%, 68.1% and 75.3%. This suggested that a sort of metal activation affect such as in situ reduction occurred during the repeated reaction. In order to confirm in situ reduction had occurred during the repeated reaction, XPS analysis of used catalyst after each reaction were carried out to study the chemical state of Ru 3d species. Narrow scan of peak Ru 3d revealed that intensity of Ru 3d5/2 peak at BE 280.0 eV which is corresponding to Ru0 species increased until three cycle reaction. This result confirmed that in situ reduction had occurred during the repeated reaction and this made the activities of the catalyst increased upon recycling due to the availability of more metallic Ru on the surface of the catalyst. This study also shows that conversion of glycerol increased linearly with the percentage atomic ratio of Ru metal active site available on the surface of catalyst.

scholarly journals Active Site Elucidation in Heterogeneous Catalysis via In Situ X-Ray Spectroscopies

2012 ◽  
Vol 65 (6) ◽  
pp. 615 ◽  
Author(s):  
Adam F. Lee
Keyword(s):  
Active Site ◽  
Heterogeneous Catalysts ◽  
Chemical Transformations ◽  
X Ray ◽  
Gas Phase Chemistry ◽  
Catalytic Sites ◽  
Artificial Photosynthetic ◽  
Phase Chemistry ◽  
Water Photooxidation

Nanostructured heterogeneous catalysts will play a key role in the development of robust artificial photosynthetic systems for water photooxidation and CO2 photoreduction. Identifying the active site responsible for driving these chemical transformations remains a significant barrier to the design of tailored catalysts, optimized for high activity, selectivity, and lifetime. This highlight reveals how select recent breakthroughs in the application of in situ surface and bulk X-ray spectroscopies are helping to identify the active catalytic sites in a range of liquid and gas phase chemistry.

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