scholarly journals The electronic structure, surface properties, and in situ N2O decomposition of mechanochemically synthesised LaMnO3

2020 ◽  
Vol 22 (34) ◽  
pp. 18774-18787
Author(s):  
Rachel H. Blackmore ◽  
Maria Elena Rivas ◽  
George F. Tierney ◽  
Khaled M. H. Mohammed ◽  
Donato Decarolis ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Surface Properties ◽  
N2o Decomposition ◽  
Catalytic Performance ◽  
Structure Surface

This study reports the importance of advanced synchrotron techniques for understanding the effect of milling atmosphere, either air or argon, on mechanochemically prepared LaMnO3 and the catalytic performance towards N2O decomposition (deN2O).

scholarly journals Ambient base-free glycerol oxidation over bimetallic PdFe/SiO2 by in situ generated active oxygen species

2021 ◽  
Author(s):  
Ricci Underhill ◽  
Mark Douthwaite ◽  
Richard J. Lewis ◽  
Peter J. Miedziak ◽  
Robert D. Armstrong ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Bimetallic Catalyst ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Active Oxygen Species ◽  
Catalytic Performance ◽  
Resonance Spectroscopy ◽  
Oxygen Species ◽  
Paramagnetic Resonance ◽  
Temperature Oxidation

AbstractLow temperature oxidation of alcohols over heterogeneous catalysts is exceptionally challenging, particularly under neutral conditions. Herein, we report on an efficient, base-free method to oxidise glycerol over a 0.5%Pd-0.5%Fe/SiO2 catalyst at ambient temperature in the presence of gaseous H2 and O2. The exceptional catalytic performance was attributed to the in situ formation of highly reactive surface-bound oxygenated species, which promote the dehydrogenation on the alcohol. The PdFe bimetallic catalyst was determined to be significantly more active than corresponding monometallic analogues, highlighting the important role both metals have in this oxidative transformation. Fe leaching was confirmed to occur over the course of the reaction but sequestering experiments, involving the addition of bare carbon to the reactions, confirmed that the reaction was predominantly heterogeneous in nature. Investigations with electron paramagnetic resonance spectroscopy suggested that the reactivity in the early stages was mediated by surface-bound reactive oxygen species; no homogeneous radical species were observed in solution. This theory was further evidenced by a direct H2O2 synthesis study, which confirmed that the presence of Fe in the bimetallic catalyst neither improved the synthesis of H2O2 nor promoted its decomposition over the PdFe/SiO2 catalyst.

scholarly journals Mesoscopic simulations of the in situ NMR spectra of porous carbon based supercapacitors: Electronic structure and adsorbent reorganisation effects

2021 ◽  
Author(s):  
Anagha Sasikumar ◽  
Anouar Belhboub ◽  
Camille Bacon ◽  
Alexander C. Forse ◽  
John Griffin ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Nmr Spectroscopy ◽  
Molecular Species ◽  
Porous Carbon ◽  
Nmr Spectra ◽  
Charge Storage ◽  
In Situ Nmr Spectroscopy ◽  
In Situ Nmr ◽  
Carbon Based

In situ NMR spectroscopy is a powerful technique to investigate charge storage mechanisms in carbon-based supercapacitors thanks to its ability to distinguish ionic and molecular species adsorbed in the porous...

In situ growth of ultrathin Ni–Fe LDH nanosheets for high performance oxygen evolution reaction

2017 ◽  
Vol 4 (7) ◽  
pp. 1173-1181 ◽  
Author(s):  
Haidong Yang ◽  
Sha Luo ◽  
Yun Bao ◽  
Yutong Luo ◽  
Jun Jin ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
High Performance ◽  
Copper Foil ◽  
Catalytic Performance ◽  
In Situ Growth ◽  
Ultrathin Nanosheet

The ultrathin Ni70Fe30LDH nanosheets were successfullyin situgrown on anodic polarized copper foil, denoted as u-Ni70Fe30LDHs/a-CF. Benefiting from the ultrathin nanosheet structure, the catalyst exhibits remarkable catalytic performance for OER in 1 M KOH solution.

scholarly journals Stoichiometry and disorder influence over electronic structure in nanostructured VOx films

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
A. D’Elia ◽  
S. J. Rezvani ◽  
N. Zema ◽  
F. Zuccaro ◽  
M. Fanetti ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Distorted Octahedral Geometry ◽  
Edge Structure ◽  
Distorted Octahedral ◽  
X Ray Absorption ◽  
Complex Matter ◽  
Nanometric Size

AbstractWe present and discuss the role of nanoparticles size and stoichiometry over the local atomic environment of nanostructured VOx films. The samples have been characterized in situ using X-ray absorption near-edge structure (XANES) spectroscopy identifying the stoichiometry-dependent fingerprints of disordered atomic arrangement. In vanadium oxides, the ligand atoms arrange according to a distorted octahedral geometry depending on the oxidation state, e.g. trigonal distortion in V2O3 and tetragonal distortion in bulk VO2. We demonstrate, taking VO2 as a case study, that as a consequence of the nanometric size of the nanoparticles, the original ligands symmetry of the bulk is broken resulting in the coexistence of a continuum of distorted atomic conformations. The resulting modulation of the electronic structure of the nanostructured VOx as a function of the oxygen content reveals a stoichiometry-dependent increase of disorder in the ligands matrix. This work shows the possibility to produce VOx nanostructured films accessing new disordered phases and provides a unique tool to investigate the complex matter.

Sign in / Sign up

Export Citation Format

Share Document