Understanding microscopic mechanism of multi-electron multi-proton transfer reactions at complexed systems is important for advancing electrochemistry-oriented science in the 21st century.

The issue of hydrogen (H) electroadsorption on Pt(111) is revisited to settle its theoretical description within the conventional ultrahigh vacuum (UHV) surface modeling and the semilocal Kohn–Sham level of the density functional theory (DFT). By performing a converged DFT calculation, we have confirmed nearly degenerated nature of H on the fcc hollow site (Hfcc) and H on the top site (Htop) when the nuclei are treated classically, while Hfcc is significantly more stable when the zero-point energy correction is applied. Relative abundance of the Hfcc over Htop was investigated by performing a Monte Carlo simulation using a lattice gas model parameterized by the DFT calculation. By comparing the calculated results with recent cyclic voltammetry data, we found good agreement between theory and experiment but minor discrepancy exists in that the H–H interaction is underestimated by ~10%. Possible origin of the discrepancy is the hydration effect neglected in our model although we cannot exclude the possibility that error of the semilocal approximation within DFT will also play a role

The proton conductivity maximum in doped BaZrO₃ is explained by a percolation vs. many-body trapping picture using first-principles thermodynamics calculations.

Increased Coulomb repulsion from surface states substantially modulates quantum confinement in topological semimetal nanofilms.

Nuclear quantum effect and many-body interaction importantly interplay in the hydrogen on the Pt(111) system under the high coverage conditions of electrochemical interest, as revealed by our ab initio path integral and ring polymer molecular dynamics simulations done at room temperature. At the full monolayer coverage, hydrogen atoms are close-packed either at the atop sites or the fcc sites owing to their strong repulsion and the nearly degenerate nature of the adsorption sites. While at the 2/3 monolayer, they are delocalized over the fcc and hcp sites via the bridge sites because of the hopping. The quantum many-body effect is thus crucially important in determining the coverage dependence and provides a clue for reconciling the long-standing controversy on this system.

By employing first-principles total-energy calculations we studied the electronic and structural properties of the ${\mathrm{NiSi}}_{\mathrm{2}}\mathrm{/Si(001)}$ and ${\mathrm{CoSi}}_{\mathrm{2}}\mathrm{/Si(001)}$ interfaces. We found a new structural model that is energetically more stable than previously proposed models and well explains an experimentally observed $\text{2×1}$ interfacial ordering. The new model is characterized by sevenfold-coordinated interface metals and interface Si dimers, and is achieved by compromising the bonding configuration of the interface metals and the reduction of the number of interface Si dangling bonds. The underlying mechanism of the model is in contrast to that of a semiconductor-surface reconstruction. Finally, the interfacial electronic properties are also presented to give a physical insight into the microscopic mechanism for the Schottky-barrier formation at metal/semiconductor junctions.