InN nanorod/Ni(OH)2 heterojunction photoelectrode for efficient photoelectrochemical water splitting

Abstract

Indium nitride (InN) is a promising photoelectrode material for photoelectrochemical (PEC) water splitting due to its strong light absorption capability, excellent electron mobility and direct band gap. However, the severe re-joining of the carrier in bulk or surface hinders the application of InN nanomaterials. Therefore, an InN nanorod/Ni(OH)₂ heterojunction for PEC water splitting with enhanced interfacial charge transfer under a biased voltage was constructed first. In this case, the Ni(OH)₂ catalyst not only has excellent electrocatalytic properties, but also can eliminate the surface state of the InN nanorods within a certain range. The improved InN/Ni(OH)₂ photoelectrodes show that the photocurrent density of 4.43 mA cm⁻², was 16 times higher than that of the pure InN nanorods (0.27 mA cm⁻²) at the same potential. Its applied bias photon-to-current efficiency (ABPE) at 0.92 V vs. Ag/AgCl was 6.92% with a 43-fold increase when compared to InN (0.16%). The work reported here, supplies practical and effective ideas to construct an InN-based nanorod heterojunction, thereby enhancing the redox reaction dynamics of the PEC water splitting in alkaline pH electrolyte.