Revisiting the Atomistic Structures at the Interface of Au(111) Electrode–Sulfuric Acid Solution

Abstract

Knowledge of atomistic structures at solid/liquid interfaces is essential to elucidate interfacial processes in chemistry, physics, and materials sciences. The (Ö3´Ö7) structure associated with a pair of sharp reversible current spikes in the cyclic voltammogram on a Au(111) electrode in sulfuric acid solution, represents one of the most classical structures at electrode/electrolyte interfaces. Although more than ten adsorption configurations have been proposed by more than ten groups in the past four decades, the atomistic structure remains ambiguous and is consequently an open problem in electrochemistry and surface science. Herein, by combining high-resolution electrochemical scanning tuning microscopy, electrochemical infrared and Raman spectroscopies, and in particular, the newly developed quantitative computational method for electrochemical infrared and Raman spectra, we unambiguously reveal that the adstructure is Au(111)(Ö3´Ö7)-(SO4•••w2) with a sulfate anion (SO4*) and two structured-water molecules (w2*) in a unit cell, and the crisscrossed [w•••SO4•••w]n and [w•••w•••]n hydrogen-bonding network comprises the symmetric adstructure. We further elucidate that the electrostatic potential energy dictates the proton affinity of sulfate anions, leading to the potential-tuned structural transformations. Our work enlightens the structural details of the inner Helmholtz plane and thus advances our fundamental understanding of the processes at electrochemical interfaces.

Probing Interfacial Electronic Effects on Single‐Molecule Adsorption Geometry and Electron Transport at Atomically Flat Surfaces

“…[1] Thus, considerable research has been undertaken to tune molecular adsorption sites,c overages,a nd geometries at surface. [2] Tailoring the interfacial electronic structure induced with organic modifiers has recently emerged as an effective and low-cost approach to optimizing adsorption processes. [3] For example,aprotic ionic liquid (IL) with high oxygen solubility was used to tailor the geometric and chemical architecture of nanoporous Ni-Pt alloy surfaces to improve ORR catalysis.…”

Revisiting the Active Sites at the MoS2/H2O Interface via Grand-Canonical DFT: The Role of Water Dissociation

“…In our approach, the electrode and adsorbates, as well as the surface charge which tunes the electrochemical potential are described via DFT while the electrolyte and solvent are represented by the solution of the linearized Poisson-Boltzmann (PB) equation. 50,51 Previously, we have successfully applied this approach not only to the characterization of the electrochemical interface, 52,53 but also to the elucidation of reaction mechanisms at electrified interfaces such as the oxygen evolution reaction on CoOOH 54 or on iron doped graphenes 55 and even for the electrochemical promotion of catalysis, 56,57 demonstrating its great versatility.…”

Advances and challenges for experiment and theory for multi-electron multi-proton transfer at electrified solid–liquid interfaces

“…Although nowadays there is a wide spectrum of ''advanced'' materials for electrocatalysis, the ''classical'' single crystal electrodes are now even more important than before to advance the field of electrode process science. 467, In these above works, the close collaborations between theory and experiment are key, as already well discussed. 362,398,[569][570][571][572][573][574] We hope that these fundamental investigations will bring knowledge to enable the study of more complicated model systems, such as MOFs/COFs and model electrocatalysts having porous structures or heterojunctions (Fig.…”