0000000000349705
AUTHOR
Minttu M. Kauppinen
Unraveling the Role of the Rh–ZrO2 Interface in the Water–Gas-Shift Reaction via a First-Principles Microkinetic Study
The industrially important water–gas-shift (WGS) reaction is a complex network of competing elementary reactions in which the catalyst is a multicomponent system consisting of distinct domains. Herein, we have combined density functional theory calculations with microkinetic modeling to explore the active phase, kinetics, and reaction mechanism of the WGS over the Rh–ZrO2 interface. We have explicitly considered the support and metal and their interface and find that the Rh–ZrO2 interface is far more active toward WGS than Rh(111) facets, which are susceptible to CO poisoning. CO2 forming on the zirconia support rapidly transforms into formate. These findings demonstrate the central role of…
DFT Prediction of Enhanced Reducibility of Monoclinic Zirconia upon Rhodium Deposition.
Oxides are an important class of materials and are widely used, for example, as supports in heterogeneous catalysis. In a number of industrial catalytic processes, oxide supports actively participate in chemical transformations by releasing lattice oxygen anions. While this is intuitively understood for reducible oxides, the reducibility of irreducible oxides may be modified via nanoengineering or upon inclusion of foreign species. Our calculations predict that the ability of irreducible monoclinic zirconia to release oxygen improves substantially upon deposition of rhodium. Through a comprehensive screening of Rh/ZrO2 with different size of the rhodium species, we find that a Rh adatom and…
Escaping scaling relationships for water dissociation at interfacial sites of zirconia-supported Rh and Pt clusters
<p>Water dissociation is an important reaction involved in many industrial processes and a good model reaction for probing the activity of catalytic sites. In this computational study, the dissociation of water at interfacial sites of globally optimized ZrO2 sup- ported Pt and Rh clusters is investigated under the framework of density functional theory. Our findings demonstrate that the perimeter sites of these small clusters can activate water, but the dissociation behavior varies considerably between sites. It is shown that the studied clusters break scaling relationships for water dissociation, suggesting these catalysts may achieve activities beyond the maximum imposed by such rel…
First-principles insight into CO hindered agglomeration of Rh and Pt single atoms on m-ZrO2
In this first-principles study we evaluate the thermodynamic and kinetic stability of Rh and Pt single-atoms (SAs) and subnano clusters on the monoclinic zirconia surface with and without a CO atmosphere. To address the kinetic stability and agglomeration of SAs to clusters and nanoparticles, a non-equilibrium nanothermodynamic approach is developed and parametrised using data computed with density functional theory. The bare subnano clusters are more stable than SA and become more so with increasing size, which means the agglomeration is always favoured. CO binds strongly to the single atoms and clusters, and our atomistic thermodynamics treatment indicates that some CO will be present eve…