Demonstration of photoreactor platform for on-sun unassisted photoelectrochemical hydrogen generation with tandem III-V photoelectrodes

Photoelectrochemical (PEC) water splitting is a direct solar-driven technology that converts solar energy to storable chemical energy in the form of hydrogen. In addition to semiconductor and catalyst development for improved photoelectrodes, designing reactors for testing and operation of PEC systems under inherently dynamic outdoor solar illumination is necessary to further the commercial viability of PEC technology. Herein, we present a versatile photoreactor system mounted on a solar tracker for outdoor PEC testing and demonstrate unassisted PEC water splitting under real world on- sun conditions. GaInP2/GaAs tandem absorber photoelectrodes with a MoS2 catalyst were fabricated and exhibit > 8% solar-to-hydrogen efficiency. On-sun efficiency and stability of the photoelectrodes were characterized on both sunny and partly cloudy days with continuous monitoring of insolation and weather conditions. The versatile photoreactor and outdoor PEC testing capabilities and methods presented here can accelerate the development of other solar fuel generating systems and technologies.

Automated summary

This article introduces a versatile photoreactor system for outdoor PEC testing and demonstrates the ability to perform photoelectrochemical water splitting under real solar illumination conditions. The GaInP2/GaAs tandem absorber photoelectrodes with a MoS2 catalyst achieved a solar-to-hydrogen efficiency of over 8%. The presented methods and capabilities can accelerate the development of other solar fuel generating systems and technologies.