New reflections on hard X-ray photon-in/photon-out spectroscopy

Lafuerza, Sara; Retegan, Marius; Detlefs, Blanka; Chatterjee, Ruchira; Yachandra, Vittal K.; Yano, Junko; Glatzel, Pieter

doi:10.1039/d0nr01983f

Cited by 23 publications

(19 citation statements)

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“…Between the pre-edge at 8977.3 eV and the peak at 8986.7 eV (Δ E = 9.5 eV), a peak appeared at about 8982.8 eV (Δ E = 5.6 eV; Figures a and S5a). The energy corresponds to the Cu + 1s to 4p transition and is hypothesized to indicate either presence of Cu + stabilized by the zeolite ,,, or is caused by beam damage due to the larger X-ray dose in HERFD-XANES. , In either form, this cation would not be actively involved in CH 4 oxidation. Figure b shows the L 3 -edge XANES of Cu-MOR-B-280 with the main peak at about 928.8 eV and distinct satellite peaks at about 932.4 and 936.5 eV.…”

Section: Resultsmentioning

confidence: 99%

Activity of Cu–Al–Oxo Extra-Framework Clusters for Selective Methane Oxidation on Cu-Exchanged Zeolites

Lee

Tao

et al. 2021

JACS Au

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Cu-zeolites are able to directly convert methane to methanol via a three-step process using O 2 as oxidant. Among the different zeolite topologies, Cu-exchanged mordenite (MOR) shows the highest methanol yields, attributed to a preferential formation of active Cu–oxo species in its 8-MR pores. The presence of extra-framework or partially detached Al species entrained in the micropores of MOR leads to the formation of nearly homotopic redox active Cu–Al–oxo nanoclusters with the ability to activate CH 4 . Studies of the activity of these sites together with characterization by 27 Al NMR and IR spectroscopy leads to the conclusion that the active species are located in the 8-MR side pockets of MOR, and it consists of two Cu ions and one Al linked by O. This Cu–Al–oxo cluster shows an activity per Cu in methane oxidation significantly higher than of any previously reported active Cu–oxo species. In order to determine unambiguously the structure of the active Cu–Al–oxo cluster, we combine experimental XANES of Cu K- and L-edges, Cu K-edge HERFD-XANES, and Cu K-edge EXAFS with TDDFT and AIMD-assisted simulations. Our results provide evidence of a [Cu 2 AlO 3 ] 2+ cluster exchanged on MOR Al pairs that is able to oxidize up to two methane molecules per cluster at ambient pressure.

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Section: Resultsmentioning

confidence: 99%

Activity of Cu–Al–Oxo Extra-Framework Clusters for Selective Methane Oxidation on Cu-Exchanged Zeolites

Lee

Tao

et al. 2021

JACS Au

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“…More recently, Ca VtC XES has been utilized to examine protonation events in Mn 3 CaO 4 -based molecular mimics of the OEC indicating that this could be an additional tool to provide mechanistic insight into biological water splitting . We note, however, that preliminary published Mn VtC XES of different S-states in the OEC catalytic cycle, suggest that the low count rates combined with rapid damage make such experiments extremely challenging …”

Section: X-ray Spectroscopic Methods and Recent Applicationsmentioning

confidence: 99%

Challenges and Opportunities for Applications of Advanced X-ray Spectroscopy in Catalysis Research

Cutsail

DeBeer

2022

ACS Catal.

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X-ray spectroscopy has had a significant and continually growing impact on catalysis research for nearly 50 years. In particular, the ability to obtain element selective electronic and geometric structural information via the X-ray absorption (XAS) edge and extended X-ray absorption fine structure regions, respectively, has been a major asset for catalysis research. In the last two decades, the development of dedicated synchrotron-based X-ray emission spectrometers has greatly expanded the range of possible experiments, enabling both nonresonant and resonant Xray emission spectroscopy experiments that can provide greater selectivity and more detailed electronic and structural information. Herein, we briefly review the range of hard X-ray photon-in, photon-out experiments that are presently possible, and highlight their recent applications in catalysis research. We also discuss the ongoing need for conventional XAS applications, either in standalone applications or in combination with more advanced approaches. The open opportunities and ongoing challenges for applying these methods, and ultimately for analyzing and interpreting the data, are also discussed.

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“…Slight beam damage was found with exposure times longer than 60 s. To avoid the damage, the scan time was set to 60 s, the sample was moved between each scan and a concentration correction scan was done after recording the RIXS plane. 44 In addition to the Ni-TPA sample, bulk polycrystalline NiO was measured as a reference. The Ni 1s2p RIXS planes were simulated using the crystal field multiplet code Quanty, 45 together with the Cripsy user interface.…”

Section: Methodsmentioning

confidence: 99%

Atomic/molecular layer deposition of Ni-terephthalate thin films

et al. 2021

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New reflections on hard X-ray photon-in/photon-out spectroscopy

Abstract: Analysis of the electronic structure and local coordination of an element is an important aspect in the study of the chemical and physical properties of materials. This is particularly relevant...

Cited by 23 publications

References 100 publications

Activity of Cu–Al–Oxo Extra-Framework Clusters for Selective Methane Oxidation on Cu-Exchanged Zeolites

Activity of Cu–Al–Oxo Extra-Framework Clusters for Selective Methane Oxidation on Cu-Exchanged Zeolites

Challenges and Opportunities for Applications of Advanced X-ray Spectroscopy in Catalysis Research

Atomic/molecular layer deposition of Ni-terephthalate thin films

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