Insight in the properties of WO3|Y: A first-principle study

Enhancing Tungsten Oxide Gasochromism with Noble Metal Nanoparticles: The Importance of the Interface

“…[64][65][66] Based on past measures, we can estimate the work function for the 15Au-WO 3 sample to be ≈3.8-4.0 eV, [64] while the work function of pristine WO 3 is ≈4.6-4.8 eV. [67,68] Such a difference in the work functions generates a net electrostatic potential at the NP-semiconductor interface whose magnitude is larger for small NPs (in this framework we are neglecting the effect the NPs themselves have on the work function of the substrate, which although present [69][70][71] is not large enough to affect our argument). The performed ab initio calculations not only support the existence of such contact potential but also suggest its possible connection with the capability to adsorb hydrogen at the interface via a heterolytic adsorption mechanism.…”

Entropy-Driven Microstructure Evolution Predicted with the Steepest-Entropy-Ascent Quantum Thermodynamic Framework

“…The system microstructure is described by a 2dimensional grid of pixels [22][23][24][25][26] whose energy is given by a q-state Potts model. This model defines a variable, q, that monitors the phase at each pixel in the system.…”

“…The system is represented by a square L × L lattice where L is the linear size in pixels. The total energy, E, of the system is the sum of the energies of all the surface and grain boundaries and is represented mathematically by the following Potts model interaction Hamiltonian [22][23][24][25][26]:…”

“…The Potts coupling constant or interaction energy, J, switches between a surface energy, γ s , and a grain boundary energy, γ gb , depending upon the identities of q n and q z . The δ on the right side represents the Kronecker delta which returns a value of 1 if the neighboring z th grain to n is of the same orientation (i.e., q n = q z ), or 0 if it is not (q n = q z ) [22][23][24][25][26]. Thus, the only contributions to the total energy come from boundaries in the system.…”

“…An example of this difference is in the calculation of the relative density. In KMC, the relative density values are commonly calculated by selecting an inner region of the sintering mass and calculating the fraction of the occupied sites versus the number of occupiable sites within the selected region [22,26,40]. Additionally, KMC simulations often utilize processes to optimize the evolution of the sintering mass, which are not replicated with the SEAQT framework.…”