A newly developed best-practices guide on photoelectrochemical (PEC) water-splitting was published in Frontiers in Energy Research. Measurements of PEC solar-to-hydrogen efficiency on identical systems can vary wildly between laboratories due to different environmental conditions and lack of standardized protocols. The new publication, authored by researchers at Lawrence Berkeley National Laboratory (LBNL) and the National Renewable Energy Laboratory (NREL) with funding from DOE EERE HFTO HydroGEN, intends to improve confidence in PEC water-splitting efficiency measurements by establishing consistent and reliable experiment and reporting practices.

“The motivation for this protocol paper was both to serve as a guide for researchers just entering the field as well as describing subtle technique tips for more experienced scientists,” said Francesca Toma, a materials staff scientist at LBNL and a co-author of the journal article. “We leveraged the unique strengths of two national labs that together span the basic to applied science realms.”

The guide covers the materials and procedures for photoelectrode fabrication, experiment setup, and measurement of solar-to-hydrogen (STH) efficiency. Direct measurement of the amount of hydrogen generated by PEC water-splitting is required for an accurate characterization of STH efficiency, the researchers noted.

The U.S. Department of Energy’s Hydrogen and Fuel Cell Technologies Office has set 25% as the ultimate target for STH through PEC water-splitting, although preliminary cost analysis suggests that competitively costed hydrogen could be achieved with lower efficiencies. Photoelectrodes have demonstrated STCH efficiencies from 10% to 20%.

Read NREL’s press release.