Generating Highly Active Partially Oxidized Platinum during Oxidation of Carbon Monoxide over Pt/Al2O3: In Situ, Time-Resolved, and High-Energy-Resolution X-Ray Absorption Spectroscopy

2008 ◽  
Vol 120 (48) ◽  
pp. 9400-9404 ◽  
Author(s):  
Jagdeep Singh ◽  
Evalyn M. C. Alayon ◽  
Moniek Tromp ◽  
Olga V. Safonova ◽  
Pieter Glatzel ◽  
...  
2015 ◽  
Vol 112 (52) ◽  
pp. 15803-15808 ◽  
Author(s):  
Ofer Hirsch ◽  
Kristina O. Kvashnina ◽  
Li Luo ◽  
Martin J. Süess ◽  
Pieter Glatzel ◽  
...  

The lanthanum-based materials, due to their layered structure and f-electron configuration, are relevant for electrochemical application. Particularly, La2O2CO3 shows a prominent chemoresistive response to CO2. However, surprisingly less is known about its atomic and electronic structure and electrochemically significant sites and therefore, its structure–functions relationships have yet to be established. Here we determine the position of the different constituents within the unit cell of monoclinic La2O2CO3 and use this information to interpret in situ high-energy resolution fluorescence-detected (HERFD) X-ray absorption near-edge structure (XANES) and valence-to-core X-ray emission spectroscopy (vtc XES). Compared with La(OH)3 or previously known hexagonal La2O2CO3 structures, La in the monoclinic unit cell has a much lower number of neighboring oxygen atoms, which is manifested in the whiteline broadening in XANES spectra. Such a superior sensitivity to subtle changes is given by HERFD method, which is essential for in situ studying of the interaction with CO2. Here, we study La2O2CO3-based sensors in real operando conditions at 250 °C in the presence of oxygen and water vapors. We identify that the distribution of unoccupied La d-states and occupied O p- and La d-states changes during CO2 chemoresistive sensing of La2O2CO3. The correlation between these spectroscopic findings with electrical resistance measurements leads to a more comprehensive understanding of the selective adsorption at La site and may enable the design of new materials for CO2 electrochemical applications.


2009 ◽  
Vol 145 (3-4) ◽  
pp. 300-306 ◽  
Author(s):  
Jagdeep Singh ◽  
Moniek Tromp ◽  
Olga V. Safonova ◽  
Pieter Glatzel ◽  
Jeroen A. van Bokhoven

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Yi-Tao Cui ◽  
Yoshihisa Harada ◽  
Hideharu Niwa ◽  
Tatsuya Hatanaka ◽  
Naoki Nakamura ◽  
...  

ChemInform ◽  
2006 ◽  
Vol 37 (38) ◽  
Author(s):  
Jeroen A. van Bokhoven ◽  
Catherine Louis ◽  
Jeffrey T. Miller ◽  
Moniek Tromp ◽  
Olga V. Safonova ◽  
...  

2006 ◽  
Vol 118 (28) ◽  
pp. 4767-4770 ◽  
Author(s):  
Jeroen A. van Bokhoven ◽  
Catherine Louis ◽  
Jeffrey T. Miller ◽  
Moniek Tromp ◽  
Olga V. Safonova ◽  
...  

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 642 ◽  
Author(s):  
Shogo Kusano ◽  
Daiju Matsumura ◽  
Kenji Ishii ◽  
Hirohisa Tanaka ◽  
Jun’ichiro Mizuki

The oxygen reduction reaction (ORR) on Pt/C in alkaline solution was studied by in situ high energy resolution X-ray absorption spectroscopy. To discuss the X-ray absorption near-edge structure (XANES), this paper introduced the rate of change of the Δμ (RCD), which is an analysis method that is sensitive to surface adsorption. The surface adsorptions as hydrogen (below 0.34 V), superoxide anion (from 0.34 V to 0.74 V), hydroxyl species (from 0.44 V to 0.74 V), atomic oxygen (above 0.74 V), and α-PtO2 (above 0.94 V) were distinguished. It is clarified that the catalytic activity in an alkaline solution is enhanced by the stability of atomic oxygen and the low stability of superoxide anion/peroxide adsorption on the platinum surface.


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