High-performing photoanodes with a cost-effective n-InGaN/p-Cu2O heterostructure for water splitting

Abstract

InGaN nanorods are highly desirable candidates for photoelectrochemical water splitting photoelectrodes because of their inherent material properties. However, their use is hindered by their low carrier separation efficiency and high production cost. Therefore, in this work, InGaN nanorods were grown by a low-cost HCVD method, and, p-n heterojunction n-InGaN/p-Cu2O photoanodes were successfully constructed by electrodeposition to address the low carrier separation efficiency. The optimized InGaN/Cu2O photoelectrodes with uniform morphology have a maximum photocurrent density of 4.2 mA cm−2 at 1.23 V vs. RHE, which is 8.4 times that of pure InGaN nanorod photoelectrodes. A comprehensive experimental study showed that this approach of constructing p-n heterojunctions greatly enhances the carrier separation efficiency and alleviates the charge transfer kinetic bottleneck at photoelectrodes.