Understanding the chemical microenvironment of electrochemical systems is crucial to developing better reactor systems. The solid-electrolyte interface (SEI) is of particular interest to our group, as we have shown that electrochemical CO2 reduction on gas diffusion electrodes must occur at the SEI. To better understand this system, we combine infrared spectroscopy (FTIR) and electrochemical atomic force spectroscopy (EC-AFM) to observe the evolution of the chemical microenvironment, especially as a function of the potential at the catalyst surface. Recep and Yuval both work with the spectroscopic systems, using infrared probes to examine surface adsorbates, including both reactants and contaminants, such as ionomers incorporating into the double layer, and reaction conditions, such as local pH. Nate and Maria focus on utilizing the EC-AFM tool to examine the catalyst itself in reaction conditions, probing the surface restructuring induced by high potentials and other local conditions of electrocatalyst of interest.