Goal 3
Goal 3: Complex Tailored Interfaces
Establish how interfacial microenvironment properties at complex interfaces determine photoelectrode ionic and electronic transport, selectivity and reactivity.
The State of the Art
At an active photoelectrode for fuels synthesis, semiconductors generate charge carriers, catalysts stabilize intermediates and guide selective transformations, and coatings and electrolytes organize the local reaction environment and engender durable operation. These components interact. Any coating modulates water structure, ion distributions, and reactant availability, altering reaction rates and selectivity. It can also affect charge transfer and material stability. The molecular origins of these coupled effects remain poorly understood. Designing an interface for a specific chemical-fuels synthesis requires coordinated materials and molecular assembly, quantitative measurements, and computations that resolve how its components function together across wide-ranging time and length scales.
LiSA’s Research
LiSA employs a co-design strategy that integrates advanced synthesis and characterization with computational and experimental insights developed under Goals 1 and 2. This approach clarifies how interface properties—such as realistic morphologies, co-catalysts, defects, impurities, buffer cations, molecular additives, and organic/inorganic coatings—collectively determine photoelectrode function.
Organic films, ionomers (polymers containing ionic groups), supported molecular catalysts, and inorganic layers at reactive fuel-generating electrochemical interfaces are used to control selectivity and durability. We measure how their composition and structure control water organization, ion distributions, and reactant delivery. These measurements test how changes in the local environment alter adsorption and reaction pathways, favoring desired fuel products and suppressing competing reactions.
Supported molecular catalysts and proton-transfer mediators provide controlled ways to vary electron and proton delivery to reaction sites. We investigate how reactants are captured, released, and activated within interfacial layers, and how these processes affect conversion rates, including the distribution of rate controlling barriers in reaction networks. Studies with impurities test how coatings exclude unwanted species and preserve useful reactivity.
Time-resolved spectroscopy and microscopy connect rapid charge generation and transfer to slower catalytic reactions and degradation. LiSA studies how these processes change with interfacial structure and investigates coatings designed to limit corrosion or regenerate during operation. Experiments are coupled with the models and quantitative benchmarks in Goals 1 and 2. The resulting understanding will establish how interface design controls function and guide materials incorporated into Goal 4’s coupled systems.