Time-resolved impact electrochemistry for quantitative measurement of single-nanoparticle reaction kinetics
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Single-nanoparticle electrochemistry has been established as a tool to characterize various nanomaterials based on the charge passed during their random impact at an electrode. Here it is demonstrated that the duration and shape of the resulting current peak can be used to quantify the reaction kinetics on a single-particle basis. Both the chemical rate constant and reaction mechanism for oxidation of single nanoparticles in different electrolytes can be determined directly from the duration of the current signal recorded in high-speed, highsensitivity current measurements. Using 29-nm-sized Ag particles in four different electrolytes as a proof of concept for this general approach, hitherto inaccessible insights into single-particle reactivity are provided. While comparable rate constants were measured for the four electrolytes at low overpotentials, transport-limited impacts at high overpotentials were found to depend strongly on the type and quantity of anions present in solution.
Keywordssingle-particle reactivity electrochemical kinetics nano-impact method silver reaction mechanism
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We thank Professor Bernhard Wolfrum (TU Munich) for fruitful discussion and Sandra Schmidt for assistance in the SEM imaging. This work was financially supported by the Cluster of Excellence RESOLV (EXC 1069) funded by the German Research Foundation (DFG) and by a NRW Rückkehrer Fellowship
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