On the verge of harnessing CO₂ as a building block for carbon-based fuels, electrocatalysis stands uniquely poised to revolutionize the chemical industry through renewable electrification. For this vision to become reality operando measurement techniques must be applied to study phenomena at the electrode-electrolyte interface. Understanding the dynamic interaction between ionic species in the electrolyte, active sites and intermediates is paramount for the systematic advancement in chemical reactivity, durability, and selectivity required to become commercially relevant. I will demonstrate a suite of operando techniques, such as shell-isolated nanoparticle enhanced Raman spectroscopy (Figure 1a), mass spectrometry (Figure 1a), and cantilever curvature measurements (Figure 1b), that enable direct measurement of adsorbates, phase state and stress dynamics, respectively, at the electrode interface. The combination of results from these measurements enables quantification of sub-monolayer coverages of surfaces species as well as coverage vs stress relationships providing the capability to effectively tune properties of the electrode surface. Complimentary use of these techniques to comprehensively study chemical reactions at heterogeneous interfaces provides new insights into atomic events critical for sustainable electrification to be realized.

Figure Caption: (a) Identification of surface hydride on Cu(111) via complementary operando Raman and online mass spectrometry measurements and (b) cantilever curvature measurements combined with DFT calculations reveal the mechanism behind compressive stress due to CO adsorption.