The Potential of Operando DRIFT Spectroscopy for Studying Degradation Mechanisms of Metal Oxide-Based Electrochemical...

High-temperature electrochemical oxide devices are promising for many applications. These devices are known to be prone to degradation, yet the mechanisms remain poorly understood. In this perspective, we summarize the techniques most used to study degradation in metal oxide electrochemical devices, examining the advantages, challenges, and limitations of each. Although charge transfer processes, structural evolution, and compositional variation underlying degradation are widely studied, surface chemistry is often neglected. Surface chemical processes evolve with temperature, gas composition, and electrochemical bias with possible intermediary degradation steps that go unseen in ex situ analyses. Direct observation is necessary to understand these pathways. Operando diffuse reflectance infrared fourier transform (DRIFT) spectroscopy is well-suited for this task. DRIFT spectroscopy offers high surface sensitivity, chemical specificity, and compatibility with elevated temperatures and reactive gas compositions. We discuss recent advances of operando DRIFT spectroscopy for metal oxide electrochemical systems, including the development of a novel high-temperature spectro-electrochemical chamber and emerging disposable reactors designed for poisoning studies. Finally, we outline strategies for coupling DRIFT spectroscopy with complementary analytical techniques. By enabling chemically resolved operando insights, DRIFT spectroscopy can advance the mechanistic understanding of degradation and inform smart design of durable metal oxide electrochemical devices.