While solid oxide fuel cell (SOFC) technologies have been evolving over many decades, little is known about the elementary-step mechanisms of the electrochemical reactions that underly their operation. Fundamental understanding of these systems is complicated by the fact that the heterogeneous electrochemical reactions take place at a three-phase boundary (an interface of electrolyte, metal, and gas phase), which is inaccessible to experimental probes. Furthermore, the reaction analysis is complicated by the fact that important chemical transformations, such as charge transfer steps, take place under high electric fields and large potential drops. Detailed knowledge of these mechanisms and the effects of external conditions—temperature, pressure, operating potential—is necessary in order to yield insights into fuel cell electro-catalysis, with the ultimate goal of the design of novel catalyst materials from first principles.
We have recently developed first principles quantum chemical approach which allows us to study electrochemical transformation at the three phase boundary (1). We will discus appropriate molecular-level model of the electrochemical processes at SOFC anodes. We will also describe how we have applied this model to study the electro-oxidation of hydrogen and hydrocarbon fuels over Ni-based SOFC anodes.