Hosted by: Matthew Sfeir

Analogues to thin-film solar photovoltaics (PV), a typical solar-fuel device consists of a hybrid inorganic-polymer composite that directly converts solar energy into H2 or liquid fuels, with inputs of sunlight, water and CO2 only. Once abundant and low-cost solar H2 is produced as a universal energy carrier, we can use it to convert synthetic or bio-fuels, upgrade petrochemical feedstock, improve combustion and produce ammonia. However, achieving such an efficient and flexible solar-fuel membrane is not trivial, particularly due to the instability of efficient semiconductor/liquid interfaces. In this talk, I will first discuss several key advances of protective coatings as a stabilization strategy. All technologically important semiconductors so far like Si and GaAs photocorrode. Although protective coatings are not prevalent in solid-state research, they are essential in the field of photoelectrochemistry. With protective coating strategies, a 10% efficient water-splitting prototype has been demonstrated. With modeling-inspired materials design, I will show a viable pathway beyond 20% efficiencies. Finally, I will discuss needs for basic research on photocatalytic processes at solid/liquid interfaces. Operando synchrotron x-ray photoelectron spectroscopy presents vast opportunities for understanding energetics of solid/liquid interfaces and for further controlling their photocatalytic processes. Understanding the change-transfer rate picture of solid/liquid interfaces promise cost-effective particle-based photocatalyst devices.