Daniel Fisher | Searcharxiv

arXiv2018

Voltage-dependent reconstruction of layered Bi$_2$WO$_6$ and Bi$_2$MoO$_6$ photocatalysts and its influence on charge separation for water splitting

We study the surface stability of the layered bismuth-oxide Bi$_2$WO$_6$ and Bi$_2$MoO$_6$ photocatalysts, which belong to the series of Aurivillius (Bi$_2$A$_{n-1}$B$_{n}$O$_{3n+3}$) perovskites and have been proposed as efficient visible-light absorbers, due to favorable electronic hybridization induced by the Bi 6s and 6p orbitals. We present a Newton--Raphson optimization of the charge distribution at the semiconductor--solution interface using the self-consistent continuum solvation (SCCS) model to describe the influence of the aqueous environment. Our analysis provides a description of the charged interface under controlled pH and applied voltage, and offers a molecular interpretation of the competing structural and electrical factors that underlie the facet-dependent photocatalytic activity of layered Bi$_2$A$_{n-1}$B$_{n}$O$_{3n+3}$ compounds.

cond-mat.mtrl-sci↗

arXiv1997

Random Walks, Reaction-Diffusion, and Nonequilibrium Dynamics of Spin Chains in One-dimensional Random Environments

Sinai's model of diffusion in one-dimension with random local bias is studied by a real space renormalization group which yields asymptotically exact long time results. The distribution of the position of a particle and the probability of it not returning to the origin are obtained, as well as the two-time distribution which exhibits "aging" with $\frac{\ln t}{\ln t'}$ scaling and a singularity at $\ln t =\ln t'$. The effects of a small uniform force are also studied. Extension to motion of many domain walls yields non-equilibrium time dependent correlations for the 1D random field Ising model with Glauber dynamics and "persistence" exponents of 1D reaction-diffusion models with random forces.

cond-mat↗