Exploring Pretreatment–Morphology Relationships: Ab Initio Wulff Construction for RuO₂ Nanoparticles under Oxidising Conditions

Abstract

We present a density-functional theory based Wulff construction of the equilibrium shape of RuO2 particles in an oxygen environment. The obtained intricate variations of the crystal habit with the oxygen chemical potential allow for a detailed discussion of the dependence on the oxidizing pretreatment observed in recent powder catalyst studies. The analysis specifically indicates an incomplete particle shape equilibration in previously employed low temperature calcination. Equilibrated particles could be active CO oxidation catalysts with long-term stability in oxidizing feed and then represent an interesting alternative to the previously suggested core-shell concept.

Orientation-Dependent Oxygen Evolution on RuO2 without Lattice Exchange

“…The relative stability of the surfaces are found to be in good agreement with previous computational work on RuO 2 surfaces and nanoparticles, 12,25 but with the interesting addition of a new oxygen rich termination on the open (111) surface, where the active Ru-site is tetrahedrally coordinated to oxygen, see Figure 3D and S21.…”

First‐Principles Computational Screening of Dopants to Improve the Deacon Process over RuO2

“…In light of the suspected limiting nature of the Cl−Cl recombination step in the Deacon process over RuO 2 and the scaling relations between O* and Cl* binding, the Cl desorption energy, Δ E Cl‐des , from the abundant RuO 2 (1 1 0) facet appears as a suitable reactivity descriptor to assess the effect of metal dopant atoms on the catalytic process. We define this desorption energy in Equation as: …”

Facet‐dependent Chlorine and Oxygen Evolution Selectivity on RuO2: An Ab initio Atomistic Thermodynamic Study

“…The surface energies of clean/unadsorbed RuO 2 (110), RuO 2 (101), RuO 2 (111), RuO 2 (001) and RuO 2 (100) are found to be 71 meV/Å 2 , 76 meV/Å 2 , 225 meV/Å 2 , 174 meV/Å 2 and 87 meV/Å 2 , respectively. Hence, RuO 2 (110) is expected to be the most abundant (lowest surface energy) facet in polycrystalline RuO 2 , which is also found to be the case in experimental studies . Wang et al .…”

“…The effect of morphology on electrochemical activity and selectivity has been previously reported . A change in morphology is caused by variation in the ratio of exposed facets, wherein the density of active sites differs . The nature of the active sites in different facets varies with the change in co‐ordination symmetry.…”