Protective Catalyst Systems on III-V and Si-based Semiconductors for Efficient, Durable Photoelectrochemical Water Splitting Devices

Recipient Stanford University (PI: Thomas Jaramillo)

Subs Stanford (PI: James Harris)

Water Splitting Technology PEC

Status Awarded

Abstract Photoelectrochemical (PEC) water splitting is a promising technology for synthesizing H2 from water and sunlight. However, for PEC water splitting to be economically competitive ( 20% and constructing an electrode that can operate continuously for 2 weeks.

The five tasks required to achieve the overall end-goals are: ((1) Translatable, thin-film catalyst and protection layer development, (2) Tandem InGaN/Si fabrication, (3) III-V fabrication and PEC device development for tandem III-V and InGaN/Si, (4) In-lab stability studies, and (5) On-sun testing at NREL. In Task 1, transition metal sulfides and phosphides will be deposited by physical and chemical vapor deposition will serve as ultrathin, optically transparent, and conformal catalysts. Task 2 focuses on a comparably cost-effective route to high efficiency via an InGaN/Si tandem system grown on Si by sputtering and metal-organic chemical vapor deposition. In Task 3 we will leverage the EMN node III-V Semiconductor Epi-structure and Device Design and Fabrication (Dr. Daniel Friedman, NREL) to fabricate III-V tandems. These Dual III-V and the InGaN/Si tandems from Task 2 will be integrated with the catalyst protecting schemes from Task 1 to create high efficiency, durable photoelectrodes. In Task 4, we will perform operando spectroscopy and microscopy to understand PEC corrosion mechanisms of the devices developed as part of Task 3 and thereby improve efficiency and stability while identifying promising candidates for on-sun testing in Task 5. To verify electrode performance in Tasks 1-4, we will utilize the Characterization of Semiconductor Bulk and Interfacial Properties EMN node (Dr. Todd Deutsch, NREL). Finally, after successful integration of catalytic and protection schemes to maximize in-lab efficiency (>20% STH efficiency) and durability (>100 hrs), we will test samples for >2 weeks under real-world operating conditions, utilizing the On-Sun Solar-to-Hydrogen Benchmarking EMN node (Dr. Todd Deutsch, NREL). The goals and outcomes built into this program provide a path toward achieving $2/kg H2 via PEC water splitting.