Water Splitting Using GaN-based Working Electrodes for Hydrogen Generation with Bias by Solar Cells

We demonstrated PEC hydrogen generation using GaN-based semiconductors as the working electrode for water splitting under solar illumination. The generation rate of hydrogen could be improved by applying external bias onto the working electrodes to enhance the separation of photogenerated electron-hole pairs in the semiconductor and the charge transfer at the interface between semiconductor and electrolyte. Instead of using an external bias provided by power supply, a solar cell (SC) was used to raise the driving force to increase the rate of hydrogen production. The bandgap of GaN is suitable for photoeletrolysis, and it is resistance to the solution. In order to increase the absorption of solar spectrum, we fabricated hybrid working electrodes, such as n-GaN and InGaN. Prove that the hybrid working electrodes with SC to bias the PEC cells could improve the efficiency of hydrogen generation.