Solid-State Reactivity at Heterophase Interfaces

Abstract

▪ Abstract Chemical reactivity at heterophase interfaces is reviewed with a special focus on metal-oxide and oxide-oxide interfaces. Equilibrium chemistry of interfaces is discussed in terms of processes at the macroscopic and atomic level. The dependency on thermodynamic and crystallographic variables is described and illustrated by experimental results. Any reaction-related motion of an interface is associated with numerous transport and reaction steps that include not only atom transfer across the interface, chemical reactions between species and defects and phase transitions, but also steps accommodating lattice mismatch and volume changes. Faceting and morphology evolution of interfaces are included in the considerations.

Crystallographic preferred orientation produced by diffusional creep of harzburgite: Effects of chemical interactions among phases during plastic flow

“…Finally, and most importantly, neither mineral has its stoichiometric composition. The presence of trace elements, none of which have equal solubility in both minerals, leads to a solute drag pinning the climb of geometrically necessary interfacial dislocations (the motion necessary to effect both grain boundary migration and sliding) [ Backhaus‐Ricoult , 2003; Sutton and Balluffi , 1996, chapter 10]. For example, the orthopyroxene in our experiments contains ∼1 wt % CaO and ∼0.7 wt % Al 2 O 3 that cannot be incorporated into olivine, while olivine contains ∼0.4 wt % NiO that is less compatible in orthopyroxene (see Table 1).…”

Interaction of nanostructured metal overlayers with oxide surfaces

“…Whereas parabolic reaction kinetics, where the reaction rate is proportional to the square root of time, is observed in case of diffusion-controlled reactions (e.g. [113]). At many metal/oxide systems, as we will see below, interface reactions at relatively low temperatures are often limited by mass transport, e.g.…”

Interface chemistry in LSM–YSZ composite SOFC cathodes

“…The approach and its application were outlined in [10][11][12][13]. The approach can be extended to oxide-oxide interfaces with transition metal cations that adopt various oxidation states.…”