<i>In situ</i> STEM study on the morphological evolution of copper-based nanoparticles during high-temperature redox reactions

Sharna, Sharmin; Bahri, Mounib; Bouillet, Corinne; Rouchon, Virgile; Lambert, Arnold; Chiche, David; Ersen, Ovidiu

doi:10.1039/d1nr01648b

Cited by 19 publications

(11 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In part, this is because the majority of the existing in situ studies are based on particle ensembles [29][30][31] and thus, suffer from averaging effects. Few in situ single particle studies of Cu oxidation using (scanning) transmission electron microscopy ((S)TEM) 18,32,33 and plasmonic nanospectroscopy 34 have been reported. However, the existing in situ (S)TEM studies focus solely on the morphological changes of the particles captured at relatively few steps during oxidation, and the plasmonic nanospectroscopy studies are inherently blind to morphological details of oxidation.…”

Section: Introductionmentioning

confidence: 99%

Competing oxidation mechanisms in Cu nanoparticles and their plasmonic signatures

et al. 2022

View full text Add to dashboard Cite

show abstract

Section: Introductionmentioning

confidence: 99%

Competing oxidation mechanisms in Cu nanoparticles and their plasmonic signatures

et al. 2022

View full text Add to dashboard Cite

show abstract

“… 4 This encompasses activation or deactivation sequences, which go along with, e.g ., reconstruction of surface and bulk structures, 6 phase transformations, 7 and redox reactions or exsolution phenomena. 8 , 9 On the most detailed microscopic level, we strive to image the active sites and local dynamics relevant for an in-depth understanding of catalytic action.…”

Section: Introductionmentioning

confidence: 99%

“…This is important insofar as the current understanding of the action of solid heterogeneous catalysts under catalytic operation is of a highly dynamic nature, where the catalyst surface and bulk quickly adapt themselves to the changes in the reaction environment . This encompasses activation or deactivation sequences, which go along with, e.g ., reconstruction of surface and bulk structures, phase transformations, and redox reactions or exsolution phenomena. , On the most detailed microscopic level, we strive to image the active sites and local dynamics relevant for an in-depth understanding of catalytic action.…”

Section: Introductionmentioning

confidence: 99%

Atomic-Scale Insights into Nickel Exsolution on LaNiO₃ Catalysts via In Situ Electron Microscopy

et al. 2021

View full text Add to dashboard Cite

Using a combination of in situ bulk and surface characterization techniques, we provide atomic-scale insight into the complex surface and bulk dynamics of a LaNiO 3 perovskite material during heating in vacuo . Driven by the outstanding activity LaNiO 3 in the methane dry reforming reaction (DRM), attributable to the decomposition of LaNiO 3 during DRM operation into a Ni//La 2 O 3 composite, we reveal the Ni exsolution dynamics both on a local and global scale by in situ electron microscopy, in situ X-ray diffraction and in situ X-ray photoelectron spectroscopy. To reduce the complexity and disentangle thermal from self-activation and reaction-induced effects, we embarked on a heating experiment in vacuo under comparable experimental conditions in all methods. Associated with the Ni exsolution, the remaining perovskite grains suffer a drastic shrinkage of the grain volume and compression of the structure. Ni particles mainly evolve at grain boundaries and stacking faults. Sophisticated structure analysis of the elemental composition by electron-energy loss mapping allows us to disentangle the distribution of the different structures resulting from LaNiO 3 decomposition on a local scale. Important for explaining the DRM activity, our results indicate that most of the Ni moieties are oxidized and that the formation of NiO occurs preferentially at grain edges, resulting from the reaction of the exsolved Ni particles with oxygen released from the perovskite lattice during decomposition via a spillover process from the perovskite to the Ni particles. Correlating electron microscopy and X-ray diffraction data allows us to establish a sequential two-step process in the decomposition of LaNiO 3 via a Ruddlesden–Popper La 2 NiO 4 intermediate structure. Exemplified for the archetypical LaNiO 3 perovskite material, our results underscore the importance of focusing on both surface and bulk characterization for a thorough understanding of the catalyst dynamics and set the stage for a generalized concept in the understanding of state-of-the art catalyst materials on an atomic level.

show abstract

“…Therefore, the amount of Cu atoms, segregated from the AuCu particle and oxidized into CuO x , was estimated to be 21, 42, 58, and 74% for the AuCuO x - T samples. However, the initially formed CuO x species on the particle surface might retard or inhibit the complete oxidation of Cu atoms into Cu 2+ , and thus the CuO x species in the AuCuO x - T samples might present as a mixture of Cu + and Cu 2+ …”

Section: Resultsmentioning

confidence: 99%

“…However, the initially formed CuO x species on the particle surface might retard or inhibit the complete oxidation of Cu atoms into Cu 2+ , and thus the CuO x species in the AuCuO x -T samples might present as a mixture of Cu + and Cu 2+ . 16 CO Oxidation. The AuCuO x -T catalysts were tested for CO oxidation at 433 K (Figure 8a).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Atomic-Scale Engineering of CuO_x–Au Interfaces over AuCu Single-Nanoparticles

Han

et al. 2022

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

A face-centered tetragonal (fct) AuCu particle with a size of 7.1 nm and an Au/Cu molar ratio of 1/1 was coated by a silica shell of 6 nm thickness. Segregation of Cu atoms from the metal particle under an oxidative atmosphere precisely mediated the CuOx–Au interfacial structure by simply varying the temperature. As raising the temperature from 473 to 773 K, more Cu atoms emigrated from the AuCu particle and were oxidized into CuOx layers that grew up to 0.8 nm in thickness. Simultaneously, the size of the Au-rich particle lowered moderately while the crystalline structure transformed from the fct phase into the face-centered cubic (fcc) phase. The CuOx–Au interface shifted from the CuOx monolayer bound to Au single-atoms to Au@CuOx core–shell geometry, while the catalytic activity for CO oxidation at 433 K decreased dramatically. Moreover, a sharp loss in activity was observed as the crystal-phase transition occurred. This change in catalytic performance was ascribed to the geometrical configuration at the interfacial sites: the synergetic effect between the fct-AuCu particle and CuOx monolayer contributed to the much higher activity, whereas the fcc-AuCu/Au particle weakened its interaction with the thicker CuOx layer and thus decreased the activity.

show abstract

In situ STEM study on the morphological evolution of copper-based nanoparticles during high-temperature redox reactions

Abstract: Despite the broad relevance of copper nanoparticles in industrial applications, the fundamental understanding of oxidation and reduction of copper at the nanoscale is still a matter of debate and remains...

Cited by 19 publications

References 62 publications

Competing oxidation mechanisms in Cu nanoparticles and their plasmonic signatures

Competing oxidation mechanisms in Cu nanoparticles and their plasmonic signatures

Atomic-Scale Insights into Nickel Exsolution on LaNiO₃ Catalysts via In Situ Electron Microscopy

Atomic-Scale Engineering of CuO_x–Au Interfaces over AuCu Single-Nanoparticles

Contact Info

Product

Resources

About

In situ STEM study on the morphological evolution of copper-based nanoparticles during high-temperature redox reactions

Abstract: Despite the broad relevance of copper nanoparticles in industrial applications, the fundamental understanding of oxidation and reduction of copper at the nanoscale is still a matter of debate and remains...

Cited by 19 publications

References 62 publications

Competing oxidation mechanisms in Cu nanoparticles and their plasmonic signatures

Competing oxidation mechanisms in Cu nanoparticles and their plasmonic signatures

Atomic-Scale Insights into Nickel Exsolution on LaNiO3 Catalysts via In Situ Electron Microscopy

Atomic-Scale Engineering of CuOx–Au Interfaces over AuCu Single-Nanoparticles

Contact Info

Product

Resources

About

Atomic-Scale Insights into Nickel Exsolution on LaNiO₃ Catalysts via In Situ Electron Microscopy

Atomic-Scale Engineering of CuO_x–Au Interfaces over AuCu Single-Nanoparticles