On the Promotion of Catalytic Reactions by Surface Acoustic Waves.
Angew Chem Int Ed Engl
; 59(45): 20224-20229, 2020 Nov 02.
Article
in En
| MEDLINE
| ID: mdl-32729648
ABSTRACT
Surface acoustic waves (SAW) allow to manipulate surfaces with potential applications in catalysis, sensor and nanotechnology. SAWs were shown to cause a strong increase in catalytic activity and selectivity in many oxidation and decomposition reactions on metallic and oxidic catalysts. However, the promotion mechanism has not been unambiguously identified. Using stroboscopic X-ray photoelectron spectro-microscopy, we were able to evidence a sub-nanosecond work function change during propagation of 500â
MHz SAWs on a 9â
nm thick platinum film. We quantify the work function change to 455â
µeV. Such a small variation rules out that electronic effects due to elastic deformation (strain) play a major role in the SAW-induced promotion of catalysis. In a second set of experiments, SAW-induced intermixing of a five monolayers thick Rh film on top of polycrystalline platinum was demonstrated to be due to enhanced thermal diffusion caused by an increase of the surface temperature by about 75â
K when SAWs were excited. Reversible surface structural changes are suggested to be a major cause for catalytic promotion.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Angew Chem Int Ed Engl
Year:
2020
Document type:
Article
Affiliation country:
Germany