Ab initio molecular dynamics simulations are presented of vibrational dynamics and spectra of crystal HCl hydrates. Depending on the composition, the hydrates include distinct protonated water forms, which in their equilibrium structures approximate either the Eigen ion H3O+(H2O)3 (in the hexahydrate) or the Zundel H2O...H+...OH2 ion (in the di- and trihydrate). Thus, the hydrates offer the opportunity to study spectra and dynamics of distinct species of protonated water trapped in a semirigid solvating environment. The experimentally measured spectra are reproduced quite well by BLYP/DZVP-level calculations employing Fourier transform of the system dipole. The large overall width (800-1000 cm-1) of structured proton bands reflects a broad range of solvating environments generated by crystal vibrations. The aqueous HCl solution was also examined in search of an objective criterion for separating the contributions of "Zundel-like" and "Eigen-like" protonated forms. It is suggested that no such criterion exists since distributions of proton-related structural properties appear continuous and unimodal. Dipole derivatives with respect to OH and O...H+ stretches in water and protonated water were also investigated to advance the understanding of the corresponding IR intensities. The effects of H bonding and solvation on the intensities were analyzed with the help of the Wannier centers' representation of electron density.

No abstract

The electroreduction of CO32− ions on a molybdenum cathode in a NaCl-KCl-Li2CO3 melt was studied by cyclic voltammetry. The electrochemical synthesis of Mo2C on molybdenum substrates has been performed at 1123 K for 7 h with a cathodic current density of 5 mA cm−2. If molybdenum carbide is present as a thin (ca. 500 nm) film on a molybdenum substrate (Mo2C/Mo), its catalytic activity in the water gas-shift reaction is enhanced by at least an order of magnitude compared to that of the bulk Mo2C phase.

The joint electroreduction of CO 3 2-and MoO 4 2-ions on a molybdenum cathode in a NaCl-KCl-Li 2 CO 3 -Na 2 MoO 4 melt was studied by cyclic voltammetry. The electrochemical synthesis of Mo 2 C on molybdenum and graphite substrates has been performed. In all cases Mo 2 C coatings with the hexagonal lattice were obtained. The molybdenum carbide coatings on a molybdenum substrate (Mo 2 C/Mo) show catalytic activity in the water gas shift (WGS) reaction at least three orders of magnitude higher than that of the bulk Mo 2 C phase. It was found that the H 2 S does not affect on the activity, stability, and selectivity of the catalyst.