Journal
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume 142, Issue 24, Pages 10646-10658Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jacs.9b09362
Keywords
-
Categories
Funding
- RSF [17-13-01274]
- RFBR [17-03-00619a]
- Danish Council for Independent Research [DFF 4093-00297]
Ask authors/readers for more resources
Electrochemical electron transfer (ET) of transition metal complexes or redox metalloproteins can be catalyzed by more than an order of magnitude by molecular scale metallic nanoparticles (NPs), often rationalized by concentration enhancement of the redox molecules in the interfacial region, but collective electronic AuNP array effects have also been forwarded. Using DFT combined with molecular electrochemical ET theory we explore here whether a single molecular scale Au nanocluster (AuC) between a Au (1 1 1) surface and the molecular redox probe ferrocene/ferricinium (Fc/Fc(+)) can trigger an ET rate increase. Computational challenges limit us to AunCs (n up to 147), which are smaller than most electrocatalytic AuCs studied experimentally. AuC-coating thiols are addressed both as adsorption of two S atoms at the structural Au-55 bridge sites and as superexchange of variable-size AuCs via a single six-carbon alkanethiyl bridge. Our results are guiding, but enable comparing many AuC surface details (apex, ridge, face, direct vs superexchange ET) with a planar Au(1 11) surface. The rate-determining electronic transmission coefficients for ET between Fc/Fc(+) and AuC are highly sensitive to subtle AuC electronic features. The transmission coefficients mostly compete poorly with direct Fc/Fc(+) ET at the Au(1 1 1) surface, but Fc/Fc(+) 100 face-bound on Au(79 )and Au-147, and ridge bound on Au-19 leads to a 2- or 3-fold rate enhancement, in different distance ranges. Single AuCs can thus indeed cause rate enhancement of simple electrochemical ET, but additional, possibly collective AuNC effects, as well as larger clusters and more complete coating layers, also need to be considered.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available