February 15, 2018
11:00 AM - 12:00 PM
Speaker: Joaquin Rodriguez-Lopez
Assistant Professor, Department of Chemistry and Beckman Institute
The University of Illinois at Urbana-Champaign
Title: “Titrating Reactive Intermediates at Operating Water-Splitting Photoanodes: Elucidating Spatial, Temporal, and Chemical Heterogeneities”
Chemical transformation at the semiconductor/electrolyte interface for processes in energy, water remediation, and catalysis is enabled by the complex interplay of photogenerated charge carriers and surface chemical intermediates. I will describe unique electroanalytical tools developed in my laboratory for quantifying chemical processes and intermediates on water oxidation (photo)anodes with high temporal and spatial resolution, as well as chemical specificity. Our powerful toolset is based on scanning electrochemical microscopy (SECM), Figure 1. Using a combination of product collection modes (O2, H2O2), redox mediator-based measurements, and transient redox titrations we are gaining quantitative insight into the role of local perturbations in conditioning, controlling and encoding reactivity on photoelectrochemical interfaces. My discussion will include the inspection of electrode processes on wide-bandgap and solar photoelectrodes, as well as in nano-patterned surfaces and electrocatalysts. New in situ methods capable of approaching the surface dynamics of operating photocatalysts are required to provide a new leap in the design of photochemical interfaces for important processes in water environmental and energy applications.