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[2] viXra:2001.0338 [pdf] submitted on 2020-01-17 08:49:56
Authors: Mathies V. Evers, Miguel Bernal, Beatriz Roldan Cuenya, Kristina Tschulik
Comments: 9 Pages.
The impact of individual HAuCl4 nanoreactors is measured electrochemically, which provides operando insights and precise control over the modification of electrodes with functional nanoparticles of well-defined size. Uniformly sized micelles are loaded with a dissolved metal salt. These solution-phase precursor entities are then reduced electrochemically - one by one - to form nanoparticles (NPs). The charge transferred during the reduction of each micelle is measured individually and allows operando sizing of each of the formed nanoparticles. Thus, particles of known number and sizes can be deposited homogenously even on nonplanar electrodes. This is demonstrated for the decoration of cylindrical carbon fibre electrodes with 25 +/- 7 nm sized Au particles from HAuCl4-filled micelles. These Au NP-decorated electrodes show great catalyst performance for ORR (oxygen reduction reaction) already at low catalyst loadings. Hence, collisions of individual precursor-filled nanocontainers are presented as a new route to nanoparticle-modified electrodes with high catalyst utilization.
Category: Chemistry
[1] viXra:2001.0337 [pdf] submitted on 2020-01-17 08:58:33
Authors: Alexander Bagger, Rosa M. Arán-Ais, Joakim Halldin Stenlid, Egon Campos dos Santos, Logi Arnarson, Kim Degn Jensen, María Escudero-Escribano, Beatriz Roldan Cuenya, Jan Rossmeisl
Comments: Pages.
Electrochemical reactions depend on the electrochemical interface; between the catalytic surfaces and the electrolytes. To control and advance electrochemical reactions there is a need to develop realistic simulation models of the electrochemical interface to understand the interface from an atomistic point-of-view. Here we present a method for obtaining thermodynamic realistic interface structures, a procedure to derive specific coverages and to obtain ab initio simulated cyclic voltammograms. As a case study, the method and procedure is applied in a matrix study of three Cu facets in three different electrolyte. The results are validated by a direct comparison with experimental cyclic voltammograms. The alkaline (NaOH) electrolyte CV are described by H* and OH*, while neutral (KHCO3) the CO3* species are present and in acidic (KCl) the Cl* species dominate. An almost one-to-one mapping is observed from simulation to experiments giving an atomistic understanding of the interface structure of the Cu facets. The strength of atomistic understanding the interface at electrolyte conditions will allow realistic investigations of electrochemical reactions in future studies.
Category: Chemistry
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