Effects of La-doping on charge separation behavior of ZnO:GaN for its enhanced photocatalytic performance

Abstract

In this work, lanthanum (La) has been proven as an effective space charge layer modifier to promote efficient photogenerated charge carrier separation for ZnO:GaN solid solution photocatalysts with enhanced photocatalytic water-splitting performance. Photogenerated electron–hole pairs are effectively separated due to the increase of the thickness of the space charge layer after La-doping. The stable photocatalytic activity of the ZnO:GaN solid solution photocatalysts for overall water-splitting was remarkably enhanced by about 3.4 times when the La-doping concentration was 3% in atom ratio. The maximum apparent quantum efficiency of the La-doped (3% in atom percentage) ZnO:GaN solid solution photocatalyst for photocatalytic water oxidation was up to 14.5% at 350 nm without loading of any co-catalyst.