| Full text | |
| Author(s): |
Cassinelli, Wellington H.
[1]
;
Martins, Leandro
[1]
;
Passos, Aline R.
[2, 1]
;
Pulcinelli, Sandra H.
[1]
;
Santilli, Celso V.
[1]
;
Rochet, Amelie
[2]
;
Briois, Valerie
[2]
Total Authors: 7
|
| Affiliation: | [1] Univ Estadual Paulista, UNESP, Inst Quim, BR-14800900 Araraquara, SP - Brazil
[2] Synchrotron SOLEIL, F-91192 Gif Sur Yvette - France
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | CATALYSIS TODAY; v. 229, p. 114-122, JUN 15 2014. |
| Web of Science Citations: | 43 |
| Abstract | |
The pure X-ray Absorption (XAS) spectral constituents and related concentration profiles characterizing the reduction of a copper-based catalyst supported on hierarchically porous alumina were disentangled from a set of time-resolved Quick-XAS using a Multivariate Curve Resolution-methodology. First, the number of components involved in the data set and the range of existence of intermediate species were determined by Principal Component Analysis (PCA). Then, a Multivariate Curve Resolution with Alternating Least Squares fitting of the set of time-resolved Quick-XANES was performed using the constraints of non-negativity of both absorption and concentration and of closure of concentration. Consideration about the strategy of use of the chemometric methods and robustness regarding the reliability of results for time-resolved XAS data is discussed. The intermediate copper species determined by MCR-ALS is at the monovalent oxidation state and characterized by a local order of 2 oxygen atoms at 1.915 angstrom. Upon isothermal treatment under 60% H-2/He at 250 degrees C for 30 min, the intermediate species appears quite resistant to complete copper reduction. Copper speciation obtained using MCR-ALS method leads to very different results than those obtained using bulk CuO, Cu2O and metallic Cu as constituents, MCR-ALS concentration profile so-determined being fully consistent with the reducibility of the catalyst measured by TPR. (C) 2013 Elsevier B.V. All rights reserved. (AU) | |
| FAPESP's process: | 07/53073-4 - Mesoporous ceramics and multifunctional organic-inorganic hybrids prepared by sol-gel process |
| Grantee: | Celso Valentim Santilli |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 13/05346-2 - E-MRS 2013 Spring Meeting |
| Grantee: | Wellington Henrique Cassinelli |
| Support Opportunities: | Research Grants - Meeting - Abroad |