Stochastic Analysis of Electron Transfer and Mass Transport in Confined Solid/Liquid Interfaces

Abstract

Molecular-level understanding of electrified solid/liquid interfaces has recently been enabled thanks to the development of novel in situ/operando spectroscopic tools. Among those, ambient pressure photoelectron spectroscopy performed in the tender/hard X-ray region and coupled with the “dip and pull” method makes it possible to simultaneously interrogate the chemical composition of the interface and built-in electrical potentials. On the other hand, only thin liquid films (on the order of tens of nanometers at most) can be investigated, since the photo-emitted electrons must travel through the electrolyte layer to reach the photoelectron analyzer. Due to the challenging control and stability of nm-thick liquid films, a detailed experimental electrochemical investigation of such thin electrolyte layers is still lacking. This work therefore aims at characterizing the electrochemical behavior of solid/liquid interfaces when confined in nanometer-sized regions using a stochastic simulation approach. The investigation was performed by modeling (i) the electron transfer between a solid surface and a one-electron redox couple and (ii) its diffusion in solution. Our findings show that the well-known thin-layer voltammetry theory elaborated by Hubbard can be successfully applied to describe the voltammetric behavior of such nanometer-sized interfaces. We also provide an estimation of the current densities developed in these confined interfaces, resulting in values on the order of few hundreds of nA·cm−2. We believe that our results can contribute to the comprehension of the physical/chemical properties of nano-interfaces, thereby aiding to a better understanding of the capabilities and limitations of the “dip and pull” method.

Oxidation of Aqueous Phosphorous Acid Electrolyte in Contact with Pt Studied by X-ray Photoemission Spectroscopy

“…reference electrode (ET072, eDAQ). The solid/liquid interface was created using the “Dip-and-pull” method. − The incoming X-rays were monochromatized using the Si (111) crystal pair of a double crystal monochromator and kept at an energy of 3 keV. The measurements were conducted with a beam spot of approximately 400 μm × 700 μm .…”

pH jump kinetics in colliding microdroplets: accelerated synthesis of azamonardine from dopamine and resorcinol

“…Kinetiscope has been used to accurately describe a wide range of chemical reactions in droplets, aerosols and emulsions with equivalent accuracy to solving systems of differential equations. 25,41–44…”

“…Kinetiscope has been used to accurately describe a wide range of chemical reactions in droplets, aerosols and emulsions with equivalent accuracy to solving systems of differential equations. 25,[41][42][43][44] Rate constants for this reaction are constrained where possible using prior literature. Table S1 † shows the rate constants for the ve reaction steps in Fig.…”

Study of the behavior and determination of phenol Based on modified carbon pa s te electrode with nickel oxide-nitrogen carbon quantum dots using cyclic voltammetry

“…It has three cases: reversible, quasi-reversible, or irreversible [26]. Cyclic voltammetry can provide kinetic and mechani s tic information; as such: Diffusion coefficient (D) [27][28][29][30], mass transport (m trans ) [31][32][33], Charge Transfer Coefficient (α. n α ), [34], and con s tant K 0 [35], the highe s t occupied molecular orbital (HOMO), lowe s t unoccupied molecular orbital (LUMO) [36,37], Gibbs free energy (ΔG) [38] and interface trap density (Dit) [39]. The diffusion coefficient is calculated from Randles-Sevcik irreversible Equation 1 [27][28][29][30].…”

“…The diffusion coefficient is calculated from Randles-Sevcik irreversible Equation 1 [27][28][29][30]. The mass transport is given by Equation 2 [31][32][33]. Also, the charge transfer coefficient (CTC) is given by Equation 3 [34].…”