Title: "Heterogeneity in Electrochemical Interfaces: From Spatial Mapping to Temporal Control"

Hang Ren, Assistant Professor

University of Texas at Austin, Dept of Chemistry

Host: Robbyn Anand

Abstract: Electrochemical interfaces are intrinsically heterogeneous in both space and time, yet conventional measurements average over these variations and obscure the underlying kinetics. In this presentation, I will discuss how spatially and temporally resolved electrochemical approaches can be used to quantify and control this heterogeneity. First, we use scanning electrochemical cell microscopy (SECCM) as a localized electrochemical platform with well-defined mass transport to probe spatial variations in reactivity. By integrating correlative microscopy analysis, we establish direct links between interfacial structure and electrochemical response, and further interpret spatially resolved measurements in terms of distributions of intrinsic kinetics. These concepts are illustrated through mapping facet-dependent activity and selectivity, as well as probing stochastic nucleation processes at individual sites, revealing site-specific kinetic barriers.

We then extend this framework to the temporal domain by introducing dynamic electrochemical control. Using time-dependent potential waveforms, we demonstrate that reaction kinetics can be modulated in time, enabling control over activity and selectivity that is inaccessible under steady-state conditions. This dynamic modulation provides a complementary dimension to spatial mapping, revealing the non-static nature of electrochemical interfaces.

Together, these results suggest that electrochemical reactivity is governed by coupled spatial and temporal heterogeneity. This perspective provides a pathway toward quantitatively understanding and actively controlling electrochemical interfaces for energy conversion and materials synthesis.