LLNL scientist researching hydrogen energy from solar water splitting

A Lawrence Livermore National Laboratory (LLNL) scientist and collaborators are working on generating hydrogen, a carbon-free energy source, from sunlight and water.

The technology uses photoelectrochemical cells (PECs), which absorb sunlight and drive water-splitting reactions to produce hydrogen.

LLNL’s Lawrence Fellow Anh Pham, Assistant Professor Yuan Ping from the University of California at Santa Cruz and Professor Giulia Galli from the University of Chicago and Argonne National Laboratory reviewed the methods used to understand the interfaces between photoabsorbers, electrolytes and catalysts in PECs.

In order to be successful and scalable, PECs must be efficient, low-cost and long lasting. Building an efficient PEC requires a high volume of semiconducting photoelectrode materials.

“Despite steady efforts and some breakthroughs, no single material has yet been found that simultaneously satisfies the efficiency and stability required for the commercialization of PEC hydrogen production technology,” Pham said.

The research, which appeared in the journal Nature Materials at the beginning of January, shows that understanding the properties of the interfaces between a PEC’s components is crucial for predicting new, better suited materials that could optimize its performance.

In this study, the team reviewed open challenges in describing PEC interfaces using established techniques, concentrating on the interaction between their structural and electronic properties. The scientists also evaluated first-principles techniques applicable to the study of solid-liquid interfaces, the structural and electronic properties of photoelectrode-water and photoelectrode-catalyst water interfaces and open theoretical challenges in the simulation of PEC interfaces.

The National Science Foundation Centers for Chemical Innovation Grant and the Lawrence Fellowship funded the work.