Oxygen vacancies on Pd/TiO2 are detected at low pressures by ESR spectroscopy at ambient temperatures

Download

index.pdf

Date

2022-1-01

Author

Üner, Deniz
Yarar, Melis

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

107
views

24
downloads

All rights reserved.A low field benchtop electron spin resonance (ESR) (also referred to as electron paramagnetic resonance (EPR)) spectrometer is used to reveal paramagnetic centres such as oxygen vacancies and Ti+3 centres over 0.5%Pd/TiO2. The measurement was performed at room temperature after the sample was reduced in situ under mild hydrogen pressures and evacuated to P < 10–6 Torr. The measurement was possible due to a T1 compensation effect under vacuum: Correlation times at low pressures enabled sufficient line narrowing and detection of the ESR signal, justifying a method using benchtop spectrometers coupled to vacuum manifolds. The method justification was demonstrated using similar measurements performed on a reference compound, Mn(II) in plasticine: a measurement performed by saturation recovery technique revealed that T1 of the signal due to Mn(II) was smaller in vacuum than its atmosphere exposed counterpart. By applying vacuum, the ESR spectra of 0.5%Pd/TiO2 were collected at ambient temperatures, with features equivalent to the published data obtained at cryogenic temperatures.

Subject Keywords

low pressure ESR, room temperature electron paramagnetic resonance (EPR), Room temperature electron spin resonance (ESR), saturation-recovery CW-ESR

URI

https://hdl.handle.net/11511/101792

Journal

Turkish Journal of Chemistry

DOI

https://doi.org/10.55730/1300-0527.3416

Collections

Department of Chemical Engineering, Article

Suggestions

OpenMETU
Core

Endohedrally halogen and interhalogen substituted C-70-AM1 study Türker, Burhan Lemi (2002-12-09) C-70 structure having a certain halogen (Cl-2, Br-2, I-2) or interhalogen molecule (BrCl, ICl, IBr) as the endohedral substituent was considered for semiempirical quantum chemical calculations at the level of AMI (RHF). All the endohedrally monosubstituted systems were found to be stable (inversely related to the bulkiness of the substituent) but endothermic (directly related to the size of the substituent). Some electronic and physicochemical properties of these systems were also reported.
Direct epoxidation of propylene to propylene oxide on various catalytic systems: A combinatorial micro-reactor study Kalyoncu, Sule; Duzenli, Derya; Önal, Işık; Seubsai, Anusorn; Noon, Daniel; Senkan, Selim (2015-02-10) A combinatorial approach is used to investigate several bimetallic catalytic systems and the promoter effect on these catalysts to develop highly active and selective catalysts for direct epoxidation of propylene to propylene oxide (PO) using molecular oxygen. 2%Cu/5%Ru/c-SiO2 catalyst yielded the highest performance with high propylene conversion and PO selectivity among the bimetallic catalytic systems including silver, ruthenium, manganese and copper metals. On the other hand, the most effective catalyst...
Experimental and mathematical investigation of mass transfer in food andhydrogel systems using magnetic resonance imaging and NMR relaxometry Çıkrıkcı, Sevil; Öztop, Halil Mecit; Department of Food Engineering (2019) Nuclear magnetic resonance (NMR) and Magnetic Resonance Imaging (MRI) are well-known non-invasive characterization methods used in a wide range of areas; from medical to food applications. NMR experiments are conducted either through spectroscopy with high resolution systems or with relaxometery (Time Domain NMR) through mid or low field systems. Time domain NMR is primarily based on relaxation times and diffusion measurements from the signal coming from the whole sample while MRI enables to visualize the i...
Stress evolution of Ge nanocrystals in dielectric matrices Bahariqushchi, Rahim; Raciti, Rosario; KASAPOGLU, Ahmet Emre; GÜR, Emre; Sezen, Meltem; Kalay, Yunus Eren; MIRABELLA, Salvatore; Aydınlı, Alptekin (2018-05-04) Germanium nanocrystals (Ge NCs) embedded in single and multilayer silicon oxide and silicon nitride matrices have been synthesized using plasma enhanced chemical vapor deposition followed by conventional furnace annealing or rapid thermal processing in N-2 ambient. Compositions of the films were determined by Rutherford backscattering spectrometry and x-ray photoelectron spectroscopy. The formation of NCs under suitable process conditions was observed with high resolution transmission electron microscope mi...
Indirect nuclear exchange coupling and electronic structure of the chain semiconductor TlSe: A Tl-203 and Tl-205 NMR study Panich, AM; Hasanlı, Nızamı (2001-05-15) We report an NMR study of the indirect nuclear exchange coupling, electronic structure, and wave-functions overlap in the single crystal of semiconductor TlSe which has a chain structure and comprises two kinds of Tl atoms, Tl1+ and Tl3+. Strong exchange coupling among the spins of Tl1+ and Tl3+ ions, which reside in neighboring chains, is observed. This interaction is significantly stronger than the exchange coupling of the equivalent atoms within the chains. Such an interchain coupling is realized due to ...

Citation Formats

D. Üner and M. Yarar, “Oxygen vacancies on Pd/TiO2 are detected at low pressures by ESR spectroscopy at ambient temperatures,” Turkish Journal of Chemistry, vol. 46, no. 4, pp. 1081–1088, 2022, Accessed: 00, 2023. [Online]. Available: https://hdl.handle.net/11511/101792.