Bias-Assisted H[sub 2] Gas Generation in HCl and KOH Solutions Using n-Type GaN Photoelectrode

We studied H 2 gas generation using a GaN photoelectrode in both HCl and KOH solutions. The photocurrent in KOH was larger than that in HCl under a small extra bias, and caused a more extensive H 2 generation at the beginning. GaN corrosion in HCl was less extended than that in KOH during photoelectrochemical reactions. The stability of the GaN photoelectrode in HCl was a result of H 2 O reduction and Cl − oxidation instead of water photoelectrolysis.