A surface sensitive hard X-ray spectroscopic method applied to observe the surface layer reduction reaction of Co oxide to Co metal

2020 ◽  
Vol 22 (43) ◽  
pp. 24974-24977
Author(s):  
Hitoshi Abe ◽  
Yasuhiro Niwa ◽  
Masao Kimura

In situ TREXS captures surface reactions.

2015 ◽  
Vol 180 ◽  
pp. 171-190 ◽  
Author(s):  
Bridget Ingham ◽  
Monika Ko ◽  
Nick Laycock ◽  
Nigel M. Kirby ◽  
David E. Williams

We use in situ synchrotron small- and wide-angle X-ray scattering (SAXS/WAXS) to demonstrate that the formation of crystalline siderite (FeCO3) during the corrosion of steel in CO2-saturated brine – a problem of practical interest relating to the growth of protective scales on the interior surface of oil and gas production pipelines – is preceded by the formation of a colloidal precipitate in the solution and an amorphous surface layer, both assumed to be amorphous ferrous carbonate. Grazing incidence SAXS shows instantaneous film formation upon the application of an anodic potential, followed by development of a separate population of particles at later times, then by the formation of crystalline species, observed by WAXS. These observations can be interpreted in terms of crystal nucleation within the amorphous surface layer. Traces of Cr3+ in the solution significantly accelerate the precipitation rate of the colloidal precursor and accelerate the appearance of the crystalline scale. We speculate on the significance of these observations for the nucleation, growth and morphology of the corrosion scale and hence its protectiveness.


2019 ◽  
Vol 26 (6) ◽  
pp. 1940-1944
Author(s):  
Guang Chen ◽  
Yonghua Du ◽  
Pengfei An ◽  
Lirong Zheng ◽  
Shengqi Chu ◽  
...  

To illustrate the process of synchrotron radiation induced reduction of tetrachloroauric solutions, a confocal synchrotron radiation X-ray spectroscopy experiments system has been introduced to monitor the depth-resolved elemental Au distribution and chemical species during the Au reduction reaction. Combining the results from confocal X-ray spectroscopy with that from X-ray contrast imaging, the mechanism of synchrotron radiation induced Au reduction, along with the process of Au deposition, were proposed. These demonstrations provide novel avenues to spatially resolved analysis of in situ solution radiolysis.


2020 ◽  
Vol 92 (5) ◽  
pp. 733-749 ◽  
Author(s):  
Sung-Fu Hung

AbstractElectrocatalysis offers an alternative solution for the energy crisis because it lowers the activation energy of reaction to produce economic fuels more accessible. Non-noble electrocatalysts have shown their capabilities to practical catalytic applications as compared to noble ones, whose scarcity and high price limit the development. However, the puzzling catalytic processes in non-noble electrocatalysts hinder their advancement. In-situ techniques allow us to unveil the mystery of electrocatalysis and boost the catalytic performances. Recently, various in-situ X-ray techniques have been rapidly developed, so that the whole picture of electrocatalysis becomes clear and explicit. In this review, the in-situ X-ray techniques exploring the structural evolution and chemical-state variation during electrocatalysis are summarized for mainly oxygen evolution reaction (OER), hydrogen evolution reaction (HER), oxygen reduction reaction (ORR), and carbon dioxide reduction reaction (CO2RR). These approaches include X-ray Absorption Spectroscopy (XAS), X-ray diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). The information seized from these in-situ X-ray techniques can effectively decipher the electrocatalysis and thus provide promising strategies for advancing the electrocatalysts. It is expected that this review could be conducive to understanding these in-situ X-ray approaches and, accordingly, the catalytic mechanism to better the electrocatalysis.


2017 ◽  
Vol 19 (45) ◽  
pp. 30749-30755
Author(s):  
Haiying Qin ◽  
Longxia Lin ◽  
Junkang Jia ◽  
Huangliang Ni ◽  
Yan He ◽  
...  

The evolution of metallic Co to Co(OH)2 and then to CoOOH during the ORR was revealed by in situ XRD combined with in situ XAFS tests.


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